Author | Title | Year | Journal/Proceedings | Reftype | DOI/URL |
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Abbad, A., Rabenorosoa, K., Ouisse, M. and Atalla, N. | Adaptive Helmholtz resonator based on electroactive polymers: Modeling, characterization, and control | 2018 | Smart Materials and Structures Vol. 27(10) |
article | DOI URL |
Abstract: This paper presents a new concept and strategy allowing adaptive control of a membraned Helmholtz resonator (HR) embedded in a melamine foam. The designed system aims to adapt the acoustic absorption performances and transmission loss in low frequencies (<500 Hz). The proposed concept consists in replacing the resonator front wall by an electroactive polymer membrane. The stiffness of the membrane can be controlled by an electric field, resulting in a resonance frequency shift. A 2D axisymmetric numerical model based on the finite elements method is developed to characterize the complex structure-acoustic coupling between the membrane, the HR and the host foam to determine the potential of the concept. Experimental measurements are then performed in an impedance tube and compared to numerical results. A feedforward algorithm based on neural networks allows the adaptivity of the membraned HR to the acoustic excitation variation inside the impedance tube. © 2018 IOP Publishing Ltd. | |||||
BibTeX:
@article{Abbad2018, author = {Abbad, A. and Rabenorosoa, K. and Ouisse, M. and Atalla, N.}, title = {Adaptive Helmholtz resonator based on electroactive polymers: Modeling, characterization, and control}, journal = {Smart Materials and Structures}, year = {2018}, volume = {27}, number = {10}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054646288&doi=10.1088%2f1361-665X%2faad939&partnerID=40&md5=3b8cb997e689f6bda39e73896aa8c9b4}, doi = {https://doi.org/10.1088/1361-665X/aad939} } |
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Ayachi, F., Drouet, J.-M., Champoux, Y. and Guastavino, C. | Perceptual Thresholds for Vibration Transmitted to Road Cyclists | 2018 | Human Factors Vol. 60(6), pp. 844-854 |
article | DOI URL |
Abstract: Objectives: In this article, we seek to determine how sensitive road cyclists are to vertical vibration transmitted while riding a road bicycle and to propose metrics for the evaluation of dynamic comfort. Background: Road cyclists are exposed to random-type excitation due to road roughness. Vibration transmitted affects dynamic comfort. But how sensitive are cyclists to vibration level? What are the best metrics to measure the amount of vibration transmitted to cyclists? Previous studies used sinusoidal excitation with participants on rigid seats and measured acceleration. Methods: We use a psychophysical estimation of Just Noticeable Differences in Level (JNDL) for vertical vibration transmitted to cyclists on a road simulator. In Experiment 1, we estimate the JNDL for whole-body vibration using vertical excitation on both wheels simultaneously (20 male cyclists). In Experiment 2, we estimate the JNDL at two different points of contact by applying the same signal to only the hands or the buttocks (9 male cyclists). Results: The JNDLs are expressed in terms of acceleration and power transmitted to the cyclist. We compare the JNDLs expressed with these 2 metrics and measured at different points of contact. Conclusion: Using these two metrics and at all points of contact, vibration magnitude needs to be reduced by at least 15%, for the change to be detectable by road cyclists. Application: A road bicycle needs to transmit at least 15% less vibration for male cyclists to detect an improvement in dynamic comfort. Dynamic bicycle comfort can be measured in terms of a new metric: power transmitted to the cyclist. © 2018, Human Factors and Ergonomics Society. | |||||
BibTeX:
@article{Ayachi2018844, author = {Ayachi, F.S. and Drouet, J.-M. and Champoux, Y. and Guastavino, C.}, title = {Perceptual Thresholds for Vibration Transmitted to Road Cyclists}, journal = {Human Factors}, year = {2018}, volume = {60}, number = {6}, pages = {844-854}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85049040235&doi=10.1177%2f0018720818780107&partnerID=40&md5=45cb6e875e6d0bdce9305663d5de658d}, doi = {https://doi.org/10.1177/0018720818780107} } |
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Bégin, M.-A., Chouinard, P., Lebel, L.-P., Masson, P., Pasco, Y., Plante, J.-S. and Berry, A. | Experimental Assessment of a Controlled Slippage Magnetorheological Actuator for Active Seat Suspensions | 2018 | IEEE/ASME Transactions on Mechatronics Vol. 23(4), pp. 1800-1810 |
article | DOI URL |
Abstract: Passive air springs are the golden standard in heavy vehicle seat suspensions, as they provide economical means to isolate drivers from road disturbances. They are nevertheless likely to expose drivers to vibration levels higher than recommended by the ISO-2631-1 standard over a typical 8-h shift. Although existing commercial active seat suspensions have proven their superiority over passive suspensions, practical limitations such as cost or lack of overall dynamic performance have slowed down their widespread adoption. Controlled slippage magnetorheological (MR) actuators are a promising alternative because they offer a dynamic performance similar to direct-drive motors in a packaging and cost similar to economical geared motors. This paper is the first to experimentally assess the overall closed-loop performance of an active seat suspension powered by a controlled slippage MR actuator including vibration attenuation, power consumption, and seat travel. Unlike semiactive MR actuators such as MR dampers that have been extensively studied, controlled slippage MR actuators are fully active and offer a significantly better performance for rough road conditions. The active seat was tested in a laboratory on a vibrating platform recreating the floor acceleration profile of a dump truck rolling on a quarry road. The seat was also tested on an actual highway truck rolling on a roadway. Results show that with a linear-quadratic-Gaussian controller, the proposed active suspension effectively reduces floor vibrations by a factor of 2-3, while using an average power consumption of 86 W and having an average relative travel range of 1-10 mm root mean square. These results fall in line with commercially available active seat suspensions. © 1996-2012 IEEE. | |||||
BibTeX:
@article{Bégin20181800, author = {Bégin, M.-A. and Chouinard, P. and Lebel, L.-P. and Masson, P. and Pasco, Y. and Plante, J.-S. and Berry, A.}, title = {Experimental Assessment of a Controlled Slippage Magnetorheological Actuator for Active Seat Suspensions}, journal = {IEEE/ASME Transactions on Mechatronics}, year = {2018}, volume = {23}, number = {4}, pages = {1800-1810}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047003842&doi=10.1109%2fTMECH.2018.2836351&partnerID=40&md5=be63babd3e4bce4f1d1c63885ab0a769}, doi = {https://doi.org/10.1109/TMECH.2018.2836351} } |
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Bonfiglio, P., Pompoli, F., Horoshenkov, K., Rahim, M., Jaouen, L., Rodenas, J., Bécot, F.-X., Gourdon, E., Jaeger, D., Kursch, V., Tarello, M., Roozen, N., Glorieux, C., Ferrian, F., Leroy, P., Vangosa, F., Dauchez, N., Foucart, F., Lei, L., Carillo, K., Doutres, O., Sgard, F., Panneton, R., Verdiere, K., Bertolini, C., Bär, R., Groby, J.-P., Geslain, A., Poulain, N., Rouleau, L., Guinault, A., Ahmadi, H. and Forge, C. | How reproducible are methods to measure the dynamic viscoelastic properties of poroelastic media? | 2018 | Journal of Sound and Vibration Vol. 428, pp. 26-43 |
article | DOI URL |
Abstract: There is a considerable number of research publications on the acoustical properties of porous media with an elastic frame. A simple search through the Web of Science™ (last accessed 21 March 2018) suggests that there are at least 819 publications which deal with the acoustics of poroelastic media. A majority of these researches require accurate knowledge of the elastic properties over a broad frequency range. However, the accuracy of the measurement of the dynamic elastic properties of poroelastic media has been a contentious issue. The novelty of this paper is that it studies the reproducibility of some popular experimental methods which are used routinely to measure the key elastic properties such as the dynamic Young's modulus, loss factor and Poisson ratio of poroelastic media. In this paper, fourteen independent sets of laboratory measurements were performed on specimens of the same porous materials. The results from these measurements suggest that the reproducibility of this type of experimental method is poor. This work can be helpful to suggest improvements which can be developed to harmonize the way the elastic properties of poroelastic media are measured worldwide. © 2018 Elsevier Ltd | |||||
BibTeX:
@article{Bonfiglio201826, author = {Bonfiglio, P. and Pompoli, F. and Horoshenkov, K.V. and Rahim, M.I.B.S.A. and Jaouen, L. and Rodenas, J. and Bécot, F.-X. and Gourdon, E. and Jaeger, D. and Kursch, V. and Tarello, M. and Roozen, N.B. and Glorieux, C. and Ferrian, F. and Leroy, P. and Vangosa, F.B. and Dauchez, N. and Foucart, F. and Lei, L. and Carillo, K. and Doutres, O. and Sgard, F. and Panneton, R. and Verdiere, K. and Bertolini, C. and Bär, R. and Groby, J.-P. and Geslain, A. and Poulain, N. and Rouleau, L. and Guinault, A. and Ahmadi, H. and Forge, C.}, title = {How reproducible are methods to measure the dynamic viscoelastic properties of poroelastic media?}, journal = {Journal of Sound and Vibration}, year = {2018}, volume = {428}, pages = {26-43}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047061336&doi=10.1016%2fj.jsv.2018.05.006&partnerID=40&md5=262e845387d4aa32501901f277cc36c7}, doi = {https://doi.org/10.1016/j.jsv.2018.05.006} } |
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Dupont, T., Leclaire, P., Panneton, R. and Umnova, O. | A microstructure material design for low frequency sound absorption | 2018 | Applied Acoustics Vol. 136, pp. 86-93 |
article | DOI URL |
Abstract: The acoustic properties of an air-saturated porous material depend on its microstructure and the thickness of the sample. Thick samples of conventional acoustic materials are required to achieve good absorption at low frequencies. This study suggests a new micro-structure for the design of low-frequency resonant acoustic absorbers. A perforated material is studied, in which the main perforations are connected to a collection of periodically spaced very thin annular dead-end pores with respect to the lateral size, these absorbers are called multi-pancake materials. It is shown, that at low frequencies, the periodic array of annular dead-end pores increases the effective compressibility without modifying the effective dynamic density. Due to this effect, the first sound absorption peak appears at much lower frequency, compared to that of the structure without dead-end pores. A transfer matrix approach is proposed to model and optimize the absorber. Prototypes have been 3D printed and tested for sound absorption and transmission loss. This design allowed to design materials capable of producing absorption peaks at a few hundred Hz and constituted of a stacking of 10–20 annular dead-end pores, each dead-end having a thickness of the order of 1 mm or less so that the overall material thickness was of a few cm. A good agreement between the data and the model predictions is demonstrated. © 2018 Elsevier Ltd | |||||
BibTeX:
@article{Dupont201886, author = {Dupont, T. and Leclaire, P. and Panneton, R. and Umnova, O.}, title = {A microstructure material design for low frequency sound absorption}, journal = {Applied Acoustics}, year = {2018}, volume = {136}, pages = {86-93}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042480698&doi=10.1016%2fj.apacoust.2018.02.016&partnerID=40&md5=60ce570ca43ac828738093d0beb8ce8c}, doi = {https://doi.org/10.1016/j.apacoust.2018.02.016} } |
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Kesour, K. and Atalla, N. | Assessment of a Hybrid Patch Transfer-Green Functions Method for Predicting the Vibroacoustic Response of Curved Systems with Attached Noise Control Treatments | 2018 | SAE Technical Papers Vol. 2018-June(June) |
article | DOI URL |
Abstract: This article aims to assess and discuss the performances of a hybrid methodology by considering the radiation of a curved structure-cavity system with attached noise control treatments. The hybrid method uses a Patch Transfer Functions (PTF) approach to couple the standard finite element method of the curved structure and cavity with an analytical model of the sound package, i.e. Green functions based model. First, the used approach is presented. Then, the accuracy of the proposed methodology is assessed for two different curved noise control treatments, namely (i) light foam and (ii) light foam with a mass layer. The obtained results are systematically compared to three models, namely full Finite Element/Boundary Element (FEM/BEM) strategies, and to two sub-structuring approaches where the sound package is modeled by (i) a locally reacting model and (ii) FEM. It is shown that the proposed method predicts accurately and efficiently the dynamic behavior of curved trimmed vibroacoustic systems. Moreover, such hybrid approach is suitable for speeding up and facilitating the integration of acoustic treatments, especially at the early stage of the design process where several configurations of the acoustic treatments are tested with the same structure and cavity. © 2018 SAE International. All Rights Reserved. | |||||
BibTeX:
@article{Kesour2018, author = {Kesour, K. and Atalla, N.}, title = {Assessment of a Hybrid Patch Transfer-Green Functions Method for Predicting the Vibroacoustic Response of Curved Systems with Attached Noise Control Treatments}, journal = {SAE Technical Papers}, year = {2018}, volume = {2018-June}, number = {June}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050568172&doi=10.4271%2f2018-01-1572&partnerID=40&md5=886bc372b02937694c431024e9602f35}, doi = {https://doi.org/10.4271/2018-01-1572} } |
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Kesour, K. and Atalla, N. | A hybrid patch transfer-Green functions method to solve transmission loss problems of flat single and double walls with attached sound packages | 2018 | Journal of Sound and Vibration Vol. 429, pp. 1-17 |
article | DOI URL |
Abstract: This paper presents and studies the performance of a sub-structuring method that employs a patch transfer approach (PTF) to couple the standard finite element schemes of the structures and cavities with an analytical model of the sound package. First, the approach is presented followed by a convergence study to define a patch mesh criterion. Then, the accuracy of the proposed methodology is assessed for single and double wall transmission problems with two different attached noise control treatments. The obtained results are systematically compared to three models, namely full finite element/boundary element strategies (FEM/BEM), and to two sub-structuring approaches based on the modeling of the sound package by (i) a locally reacting model and (ii) FEM. It is observed that the proposed method predict accurately and efficiently the dynamic behavior of flat trimmed vibroacoustic systems. © 2018 Elsevier Ltd | |||||
BibTeX:
@article{Kesour20181, author = {Kesour, K. and Atalla, N.}, title = {A hybrid patch transfer-Green functions method to solve transmission loss problems of flat single and double walls with attached sound packages}, journal = {Journal of Sound and Vibration}, year = {2018}, volume = {429}, pages = {1-17}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047194180&doi=10.1016%2fj.jsv.2018.05.008&partnerID=40&md5=5af84ec2a0e3fad7f095b44c83648160}, doi = {https://doi.org/10.1016/j.jsv.2018.05.008} } |
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Laly, Z., Atalla, N. and Meslioui, S.-A. | Acoustical modeling of micro-perforated panel at high sound pressure levels using equivalent fluid approach | 2018 | Journal of Sound and Vibration Vol. 427, pp. 134-158 |
article | DOI URL |
Abstract: An acoustic impedance model to characterize micro-perforated panels at high sound pressure levels is proposed. The model uses a rigid frame porous medium, where the micro-perforated panel is modeled with an effective density, function of the frequency following the approach of Johnson-Allard and the equivalent fluid parameters such as the tortuosity and the flow resistivity are expressed as function of the incident sound pressure which is considered as a main variable. Unlike existing models which are limited to micro-perforated panels coupled to air cavity, the present model predicts correctly the acoustic response of micro-perforated panel backed by porous media which can be air cavity, porous material or resistive screen. Micro-perforated panel backed by porous media involves a distortion of the flow caused by the perforations through the porous media, thus the micro-perforated panel is modeled in this case using an equivalent tortuosity where a correction term is proposed to account for the flow distortion effect and it depends on the dynamic tortuosity of the porous layer and the incident sound pressure. The proposed impedance model is compared numerically with other existing nonlinear impedance models for different configurations of the micro-perforated panel. The results show a good agreement among each other for sound pressure levels up to 150 dB. In addition, experimental measurements were performed on several micro-perforated panels backed by air cavities or porous material using the classical impedance tube. A good correlation between theoretical and experimental results is obtained. Some validation and benchmarking results are illustrated and discussed in this paper. It is shown that the high sound pressure levels decrease the tortuosity and increase the flow resistivity of the micro-perforated panel. Furthermore, the acoustic energy dissipation by the micro-perforated panel absorber with a large perforation diameter which is low in the linear regime can become important and interesting at high sound pressure level. © 2017 Elsevier Ltd | |||||
BibTeX:
@article{Laly2018134, author = {Laly, Z. and Atalla, N. and Meslioui, S.-A.}, title = {Acoustical modeling of micro-perforated panel at high sound pressure levels using equivalent fluid approach}, journal = {Journal of Sound and Vibration}, year = {2018}, volume = {427}, pages = {134-158}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044722898&doi=10.1016%2fj.jsv.2017.09.011&partnerID=40&md5=d1c709d804b2b3ad73e4c77a187efda2}, doi = {https://doi.org/10.1016/j.jsv.2017.09.011} } |
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Laly, Z., Atalla, N., Meslioui, S.-A. and Bikri, K. | Modeling of acoustic lined duct with and without grazing air flow by an analytical method | 2018 | Noise Control Engineering Journal Vol. 66(4), pp. 340-352 |
article | DOI URL |
Abstract: An analytical method is proposed to characterize the sound acoustic transmission in a rectangular lined duct with and without grazing air flow. The acoustic wave number in the duct is determined using Taylor series expansion. The proposed method is validated by comparison with a finite element method in grazing air flow environment and experimental measurements at grazing sound incidence for the case with no flow. Excellent agreement is found in both configurations. The proposed method is used for sensitivity analysis of acoustic duct lined with micro perforated panel absorber in order to evaluate the impacts of the inputs parameters on the transmission loss of the duct. It is shown for a constant sound pressure level that the transmission loss of the duct is very sensitive to the cavity depth of the absorber while the resonance of the transmission at high sound pressure level is controlled by the perforation ratio of the panel. The effects of the perforation diameter and the plate thickness are negligible for higher pressure excitation and the impact of the sound pressure level on the transmission is preponderant. © 2018 Institute of Noise Control Engineering. All rights reserved. | |||||
BibTeX:
@article{Laly2018340, author = {Laly, Z. and Atalla, N. and Meslioui, S.-A. and Bikri, K.E.L.}, title = {Modeling of acoustic lined duct with and without grazing air flow by an analytical method}, journal = {Noise Control Engineering Journal}, year = {2018}, volume = {66}, number = {4}, pages = {340-352}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85052926964&doi=10.3397%2f1%2f376629&partnerID=40&md5=05424a07d9f6a4cca6b2eac1a25ef09a}, doi = {https://doi.org/10.3397/1/376629} } |
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Lecomte, P., Gauthier, P.-A., Langrenne, C., Berry, A. and Garcia, A. | Cancellation of room reflections over an extended area using Ambisonics | 2018 | Journal of the Acoustical Society of America Vol. 143(2), pp. 811-828 |
article | DOI URL |
Abstract: This paper investigates the compensation of room reflections based on Ambisonics. A multichannel room equalization method for Ambisonic playback systems is proposed. The compensation filters are designed to operate in the spherical harmonics domain, prior to the decoding step. Their design requires the inversion of a matrix which can be ill-conditioned at low frequencies and for higher Ambisonic orders. A crossover and cross-order method is proposed to circumvent this problem and to reduce the amount of necessary regularization. Simulation results are presented in frequency, space, and temporal domains over a wide-range of frequencies. It is shown that the proposed method is efficient and can reduce the reproduction error to -14 dB in the reconstruction area defined in free field. Practical considerations such as Ambisonic room response estimation and robustness of the method are investigated. Experimental results are provided and show good agreement with the theory. Finally, a glimpse into the extension of the proposed method to create three-dimensional measurement-based Ambisonic reverberation is discussed. © 2018 Acoustical Society of America. | |||||
BibTeX:
@article{Lecomte2018811, author = {Lecomte, P. and Gauthier, P.-A. and Langrenne, C. and Berry, A. and Garcia, A.}, title = {Cancellation of room reflections over an extended area using Ambisonics}, journal = {Journal of the Acoustical Society of America}, year = {2018}, volume = {143}, number = {2}, pages = {811-828}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041923219&doi=10.1121%2f1.5023326&partnerID=40&md5=7aa9a1e079d14b11131a175a128de047}, doi = {https://doi.org/10.1121/1.5023326} } |
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Marchetto, C., Maxit, L., Robin, O. and Berry, A. | Experimental prediction of the vibration response of panels under a turbulent boundary layer excitation from sensitivity functions | 2018 | Journal of the Acoustical Society of America Vol. 143(5), pp. 2954-2964 |
article | DOI URL |
Abstract: This study aims at validating an experimental method for characterizing the vibration behavior of panels excited by a turbulent boundary layer (TBL) excitation as a possible alternative to standard means like wind tunnels or in situ tests. The approach takes advantage of an explicit separation of the excitation contribution from the dynamic behavior of the panel. Based on the measurement of deterministic transfer functions on the panel, called "sensitivity functions," which are then combined with either measurements or a model of the wall-pressure fluctuations induced by the TBL excitation, the vibration response under such an excitation can be retrieved. For validation purposes, the wall-pressure fluctuations of the turbulent flow generated in an anechoic wind tunnel are measured with a flush-mounted microphone array. The decay rates and the convection velocity, which mainly characterize the excitation, are extracted from these measurements. The plate velocity response to this excitation is estimated following the proposed method using the measured sensitivity functions and the model of Mellen fed with experimentally estimated decay rates and convection velocity. A comparison between a directly measured vibration auto-spectrum under the actual flow and the one predicted following the suggested method shows satisfactory agreement. © 2018 Acoustical Society of America. | |||||
BibTeX:
@article{Marchetto20182954, author = {Marchetto, C. and Maxit, L. and Robin, O. and Berry, A.}, title = {Experimental prediction of the vibration response of panels under a turbulent boundary layer excitation from sensitivity functions}, journal = {Journal of the Acoustical Society of America}, year = {2018}, volume = {143}, number = {5}, pages = {2954-2964}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047364258&doi=10.1121%2f1.5037362&partnerID=40&md5=cbb7c7c8c55172e252f3be807afac58e}, doi = {https://doi.org/10.1121/1.5037362} } |
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Mongardon, N., Kohlhauer, M., Lidouren, F., Barretto, M., Micheau, P., Adam, C., Dhonneur, G., Ghaleh, B. and Tissier, R. | Targeted Temperature Management With Total Liquid Ventilation After Ischemic Spinal Cord Injury | 2018 | Annals of Thoracic Surgery | article | DOI URL |
Abstract: Background: Ischemic spinal cord injury is a devastating condition after aortic surgery. We determined whether ultrafast and short whole-body hypothermia provided by total liquid ventilation (TLV) attenuated lower limb paralysis after aortic cross-clamping with a targeted temperature management at 33°C versus 36°C. Methods: Anesthetized rabbits were submitted to infrarenal aortic cross-clamping during 15 min. A control group (n = 7) was maintained at normothermia (38°C to 38.5°C) with conventional mechanical ventilation. In TLV groups, TLV was started after reperfusion and maintained during 30 min with a target temperature at either 33°C or 36°C (TLV-33°C and TLV-36°C, respectively; n = 7 in each condition). After TLV, animals were resumed to conventional ventilation. Hypothermia was maintained during 120 min, before rewarming and awakening. Hind limb motor function was assessed with modified Tarlov score at day 2 and infarct size in the spinal cord was determined using triphenyltetrazolium chloride staining. Results: Target temperature was achieved within 20 minutes in the two TLV groups. At day 2, the modified Tarlov score was significantly lower in the control group, as compared with TLV-33°C and TLV-36°C groups (0.0 ± 0.0 versus 3.1 ± 0.7 and 2.6 ± 0.6, respectively). The infarct size of the spinal cord was also significantly higher in the control group compared with TLV-33°C and TLV-36°C groups (75% ± 10% versus 32% ± 7% and 28% ± 10%, respectively). Neither motor function nor infarct size differed significantly between TLV-33°C and TLV-36°C groups. Conclusions: Ultrafast hypothermic TLV attenuates spinal cord injury when applied after ischemic insult. Neurological outcome was similar with targeted temperature management at either 33°C or 36°C. © 2018 The Society of Thoracic Surgeons | |||||
BibTeX:
@article{Mongardon2018, author = {Mongardon, N. and Kohlhauer, M. and Lidouren, F. and Barretto, M. and Micheau, P. and Adam, C. and Dhonneur, G. and Ghaleh, B. and Tissier, R.}, title = {Targeted Temperature Management With Total Liquid Ventilation After Ischemic Spinal Cord Injury}, journal = {Annals of Thoracic Surgery}, year = {2018}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055633509&doi=10.1016%2fj.athoracsur.2018.06.073&partnerID=40&md5=c22e4b91dac2898bf2efb5d89a54e551}, doi = {https://doi.org/10.1016/j.athoracsur.2018.06.073} } |
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Moreau, S., Dignou, B., Jaiswal, P., Yakhina, G., Pasco, Y., Sanjose, M., Alstrom, B. and Atalla, N. | Trailing-edge noise of a at plate with several liner-type porous appendices | 2018 | 2018 AIAA/CEAS Aeroacoustics Conference | conference | DOI URL |
Abstract: This study presents a new experiment in the anechoic wind-tunnel of Université de Sherbrooke on a reference at plate with several inserts that mimic a class of porous media that are a combination of grooves and screens and were previously tested on a modified Controlled-Diffusion airfoil. Acoustic and velocity measurements have been carried out at several flow velocities for three different groove depths possibly combined with two different screens. The far-field acoustic power spectral density of the reference airfoil at plate exhibits the expected trailing-edge broadband noise with increasing vortex shedding with increased speed. The inserts with variable grooves add increasing cavity noise at high frequencies with increasing depth. A coupling between vortex shedding and cavity noise is also seen with increasing cavity depth. Cavity tones are shown to be resonances at the intersection of high order modified Rossiter modes and the cavity deepwise modes. When the screens cover the grooves the noise levels in the vortex shedding mid-frequency range are reduced. Yet for both screens, noise is regenerated in the high frequency range with a complex directivity that depends on the groove depth and type of wire-mesh. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. | |||||
BibTeX:
@conference{Moreau2018, author = {Moreau, S. and Dignou, B. and Jaiswal, P. and Yakhina, G. and Pasco, Y. and Sanjose, M. and Alstrom, B. and Atalla, N.}, title = {Trailing-edge noise of a at plate with several liner-type porous appendices}, journal = {2018 AIAA/CEAS Aeroacoustics Conference}, year = {2018}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85051288137&doi=10.2514%2f6.2018-3119&partnerID=40&md5=81ce02888008cf634e6b4c6ec74876ce}, doi = {https://doi.org/10.2514/6.2018-3119} } |
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Nadeau, J., Micheau, P. and Boisvert, M. | Collaborative control of a dual electro-hydraulic regenerative brake system for a rear-wheel-drive electric vehicle | 2018 | Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering | article | DOI URL |
Abstract: Within the field of electric vehicles, the cooperative control of a dual electro-hydraulic regenerative brake system using the foot brake pedal as the sole input of driver brake requests is a challenging control problem, especially when the electro-hydraulic brake system features on/off solenoid valves which are widely used in the automotive industry. This type of hydraulic actuator is hard to use to perform a fine brake pressure regulation. Thus, this paper focuses on the implementation of a novel controller design for a dual electro-hydraulic regenerative brake system featuring on/off solenoid valves which track an “ideal” brake force distribution. As an improvement to a standard brake force distribution, it can provide the reach of the maximum braking adherence and can improve the energy recovery of a rear-wheel-drive electric vehicle. This improvement in energy recovery is possible with the complete substitution of the rear hydraulic brake force with a regenerative brake force until the reach of the electric powertrain constraints. It is done by performing a proper brake pressure fine regulation through the proposed variable structure control of the on/off solenoid valves provided by the hydraulic platform of the vehicle stability system. Through road tests, the tracking feasibility of the proposed brake force distribution with the mechatronic system developed is validated. © 2018, IMechE 2018. | |||||
BibTeX:
@article{Nadeau2018, author = {Nadeau, J. and Micheau, P. and Boisvert, M.}, title = {Collaborative control of a dual electro-hydraulic regenerative brake system for a rear-wheel-drive electric vehicle}, journal = {Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering}, year = {2018}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046028274&doi=10.1177%2f0954407018754678&partnerID=40&md5=4b3f3f73f6dfd8845dcbe39983516a1c}, doi = {https://doi.org/10.1177/0954407018754678} } |
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Nadeau, M., Denaclara, J.-Y., Tissier, R., Walti, H. and Micheau, P. | Patient-specific optimal cooling power command for hypothermia induction by liquid ventilation | 2018 | Control Engineering Practice Vol. 77, pp. 109-117 |
article | DOI URL |
Abstract: While it is known that total liquid ventilation can rapidly cool animal subjects and improve outcomes after cardiac arrest, the temperature control strategy of the liquid ventilator for clinical use remains unknown. This work proposes to control the cooling power of the liquid ventilator in two phases. The first phase consists in a null cooling power command in order to estimate cardiac output. During the second phase, the optimal cooling power command dedicated to the estimated cardiac output is sent to the cooling system. The simulated results in human adults allow predicting the cooling performances and the overall safety. © 2018 Elsevier Ltd | |||||
BibTeX:
@article{Nadeau2018109, author = {Nadeau, M. and Denaclara, J.-Y. and Tissier, R. and Walti, H. and Micheau, P.}, title = {Patient-specific optimal cooling power command for hypothermia induction by liquid ventilation}, journal = {Control Engineering Practice}, year = {2018}, volume = {77}, pages = {109-117}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85049067210&doi=10.1016%2fj.conengprac.2018.05.007&partnerID=40&md5=24ae09b05d974b0c7ba15302a80e29d9}, doi = {https://doi.org/10.1016/j.conengprac.2018.05.007} } |
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O'Donoughue, P., Robin, O. and Berry, A. | Time-resolved identification of mechanical loadings on plates using the virtual fields method and deflectometry measurements | 2018 | Strain Vol. 54(3) |
article | DOI URL |
Abstract: This paper describes an approach for identifying the magnitude and location of both stationary and transient mechanical loadings applied to a thin rectangular simply supported plate. Full-field deflectometry measurements and the virtual fields method are used with the local equilibrium equation of the plate in the time domain to solve the force reconstruction problem, whereas previous work by the authors used this last equation in the frequency domain. As a result, it is possible to reconstruct load time history in addition to magnitude and location. Experimental results of this complete identification are presented for two different instrumented mechanical exciters: electrodynamic shaker and impact hammer for stationary and transient excitations, respectively. The approach is then applied to determine the location and time of multiple unknown transient excitations produced by a set of impacting metal marbles. © 2017 John Wiley & Sons Ltd | |||||
BibTeX:
@article{O'Donoughue2018, author = {O'Donoughue, P. and Robin, O. and Berry, A.}, title = {Time-resolved identification of mechanical loadings on plates using the virtual fields method and deflectometry measurements}, journal = {Strain}, year = {2018}, volume = {54}, number = {3}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048059530&doi=10.1111%2fstr.12258&partnerID=40&md5=ea4137780c6472142821944f18832825}, doi = {https://doi.org/10.1111/str.12258} } |
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Pelletier, A., Micheau, P. and Berry, A. | Harmonic active vibration control using piezoelectric self-sensing actuation with complete digital compensation | 2018 | Journal of Intelligent Material Systems and Structures Vol. 29(7), pp. 1510-1519 |
article | DOI URL |
Abstract: In this article, the implementation of a self-sensing piezoelectric actuator with complete digital compensation is presented. The proposed compensation not only minimizes the signal due to the electrical behavior of the self-sensing actuator but also takes into account the fact that piezoelectric actuator causes a local strain—not related to the global vibration of the plate—in a vibrating plate to which it is coupled. Therefore, the corrected measured current is related to the global vibration of the plate and may be used in an active control scheme. The electro-mechanical model on which is based this self-sensing actuator is first explained. Then, the electronic and digital processing implementation is presented, as well as the active time-harmonic control scheme used. Finally, results of experimental validation are presented, and the attenuation performance of the self-sensing actuator is compared to the performances of a co-localized accelerometer/lead zirconate titanate pair. It is shown that the corrected self-sensing actuator current gives results better than what is obtained with a co-localized sensor/actuator pair and that this technique may be used to control more than one frequency simultaneously. © 2017, © The Author(s) 2017. | |||||
BibTeX:
@article{Pelletier20181510, author = {Pelletier, A. and Micheau, P. and Berry, A.}, title = {Harmonic active vibration control using piezoelectric self-sensing actuation with complete digital compensation}, journal = {Journal of Intelligent Material Systems and Structures}, year = {2018}, volume = {29}, number = {7}, pages = {1510-1519}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045120135&doi=10.1177%2f1045389X17740978&partnerID=40&md5=b338b6461d85b92ae4c2e2972eee2128}, doi = {https://doi.org/10.1177/1045389X17740978} } |
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Quaegebeur, N., Masson, P., Berry, A., Ardin, C. and D'Anglade, P.-M. | Ultrasonic non-destructive testing of cardboard tubes using air-coupled transducers | 2018 | NDT and E International Vol. 93, pp. 18-23 |
article | DOI URL |
Abstract: Cardboard tubes are commonly used for industrial plastic film wrapping due to their low cost, high compression strength, reliability and low sensitivity to environmental changes. In order to guarantee the high radial compression strength during the manufacturing process, destructive testing such as manual peeling or non-destructive testing using acoustic impedance measurements are currently performed on a regular basis. In order to achieve a continuous quality control, automatic and non-contact inspection still need to be developed. In this paper, a method and apparatus for non-contact and rapid inspection of cardboard tubes is presented. The principle is based on the use of capacitive air-coupled transducers at frequencies below 20 kHz for generation and measurement of propagative flexural waves in a pitch-and-catch configuration. Sensitivity analysis is performed for different modes and damage types and is validated experimentally for four flaw types typically observed during the manufacturing process. Experimental validation of detection and flaw quantification is demonstrated using both amplitude and time-of-flight of wave packets at different frequencies, allowing automatic quality control of the manufacturing process. © 2017 Elsevier Ltd | |||||
BibTeX:
@article{Quaegebeur201818, author = {Quaegebeur, N. and Masson, P. and Berry, A. and Ardin, C. and D'Anglade, P.-M.}, title = {Ultrasonic non-destructive testing of cardboard tubes using air-coupled transducers}, journal = {NDT and E International}, year = {2018}, volume = {93}, pages = {18-23}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85030087289&doi=10.1016%2fj.ndteint.2017.09.011&partnerID=40&md5=f77043e8782f6afd200efea1b1294b3b}, doi = {https://doi.org/10.1016/j.ndteint.2017.09.011} } |
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Rambaud, J., Lidouren, F., Sage, M., Kohlhauer, M., Nadeau, M., Fortin-Pellerin, É., Micheau, P., Zilberstein, L., Mongardon, N., Ricard, J.-D., Terada, M., Bruneval, P., Berdeaux, A., Ghaleh, B., Walti, H. and Tissier, R. | Hypothermic total liquid ventilation after experimental aspiration-associated acute respiratory distress syndrome | 2018 | Annals of Intensive Care Vol. 8(1) |
article | DOI URL |
Abstract: Background: Ultrafast cooling by total liquid ventilation (TLV) provides potent cardio- and neuroprotection after experimental cardiac arrest. However, this was evaluated in animals with no initial lung injury, whereas out-of-hospital cardiac arrest is frequently associated with early-onset pneumonia, which may lead to acute respiratory distress syndrome (ARDS). Here, our objective was to determine whether hypothermic TLV could be safe or even beneficial in an aspiration-associated ARDS animal model. Methods: ARDS was induced in anesthetized rabbits through a two-hits model including the intra-tracheal administration of a pH = 1 solution mimicking gastric content and subsequent gaseous non-protective ventilation during 90 min (tidal volume [Vt] = 10 ml/kg with positive end-expiration pressure [PEEP] = 0 cmH2O). After this initial period, animals either received lung protective gas ventilation (LPV; Vt = 8 ml/kg and PEEP = 5 cmH2O) under normothermic conditions, or hypothermic TLV (TLV; Vt = 8 ml/kg and end-expiratory volume = 15 ml/kg). Both strategies were applied for 120 min with a continuous monitoring of respiratory and cardiovascular parameters. Animals were then euthanized for pulmonary histological analyses. Results: Eight rabbits were included in each group. Before randomization, all animals elicited ARDS with arterial oxygen partial pressure over inhaled oxygen fraction ratios (PaO2/FiO2) below 100 mmHg, as well as decreased lung compliance. After randomization, body temperature rapidly decreased in TLV versus LPV group (32.6 ± 0.6 vs. 38.2 ± 0.4 °C after 15 min). Static lung compliance and gas exchanges were not significantly different in the TLV versus LPV group (PaO2/FiO2 = 62 ± 4 vs. 52 ± 8 mmHg at the end of the procedure, respectively). Mean arterial pressure and arterial bicarbonates levels were significantly higher in TLV versus LPV. Histological analysis also showed significantly lower inflammation in TLV versus LPV group (median histological score = 3 vs. 4.5/5, respectively; p = 0.03). Conclusion: Hypothermic TLV can be safely induced in rabbits during aspiration-associated ARDS. It modified neither gas exchanges nor respiratory mechanics but reduced lung inflammation and hemodynamic failure in comparison with LPV. Since hypothermic TLV was previously shown to provide neuro- and cardio protective effects after cardiac arrest, these findings suggest a possible use of TLV in the settings of cardiac arrest-associated ARDS. © 2018, The Author(s). | |||||
BibTeX:
@article{Rambaud2018, author = {Rambaud, J. and Lidouren, F. and Sage, M. and Kohlhauer, M. and Nadeau, M. and Fortin-Pellerin, É. and Micheau, P. and Zilberstein, L. and Mongardon, N. and Ricard, J.-D. and Terada, M. and Bruneval, P. and Berdeaux, A. and Ghaleh, B. and Walti, H. and Tissier, R.}, title = {Hypothermic total liquid ventilation after experimental aspiration-associated acute respiratory distress syndrome}, journal = {Annals of Intensive Care}, year = {2018}, volume = {8}, number = {1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046654586&doi=10.1186%2fs13613-018-0404-8&partnerID=40&md5=98a1fc8158e7e1eda7a4bc6499c91734}, doi = {https://doi.org/10.1186/s13613-018-0404-8} } |
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Robin, O. and Berry, A. | Estimating the sound transmission loss of a single partition using vibration measurements | 2018 | Applied Acoustics Vol. 141, pp. 301-306 |
article | DOI URL |
Abstract: The sound transmission loss of a homogeneous, isotropic, thin panel under a diffuse acoustic field excitation is derived from a measurement of its airborne induced vibration field. Using this single dataset, the virtual fields method allows identifying the wall pressure field exciting the panel and estimating the corresponding incident acoustic power, provided that the differential operator governing the plate dynamics and its material properties are known a priori. Using the same dataset, the radiated acoustic power is calculated using the radiation resistance matrix method. For an aluminium plate, a comparison of transmission loss values obtained using this approach and a standardized measurement shows good agreement off resonance but large discrepancies on resonance and close to resonance, due to ill conditioning of the virtual fields method. A simple correction is proposed on resonance. © 2018 Elsevier Ltd | |||||
BibTeX:
@article{Robin2018301, author = {Robin, O. and Berry, A.}, title = {Estimating the sound transmission loss of a single partition using vibration measurements}, journal = {Applied Acoustics}, year = {2018}, volume = {141}, pages = {301-306}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050644343&doi=10.1016%2fj.apacoust.2018.07.015&partnerID=40&md5=6b1529bb388013c24e95118fecc6d64c}, doi = {https://doi.org/10.1016/j.apacoust.2018.07.015} } |
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Sage, M., Nadeau, M., Forand-Choinière, C., Mousseau, J., Vandamme, J., Berger, C., Tremblay-Roy, J.-S., Tissier, R., Micheau, P. and Fortin-Pellerin, É. | Assessing the impacts of total liquid ventilation on left ventricular diastolic function in a model of neonatal respiratory distress syndrome | 2018 | PLoS ONE Vol. 13(1) |
article | DOI URL |
Abstract: Background Filling the lung with dense liquid perfluorocarbons during total liquid ventilation (TLV) might compress the myocardium, a plausible explanation for the instability occasionally reported with this technique. Our objective is to assess the impacts of TLV on the cardiovascular system, particularly left ventricular diastolic function, in an ovine model of neonatal respiratory distress syndrome. Method Eight newborns lambs, 3.0 ± 0.4 days (3.2 ± 0.3kg) were used in this crossover experimental study. Animals were intubated, anesthetized and paralyzed. Catheters were inserted in the femoral and pulmonary arteries. A high-fidelity pressure catheter was inserted into the left ventricle. Surfactant deficiency was induced by repeated lung lavages with normal saline. TLV was then conducted for 2 hours using a liquid ventilator prototype. Thoracic echocardiography and cardiac output assessment by thermodilution were performed before and during TLV. Results Left ventricular end diastolic pressure (LVEDP) (9.3 ± 2.1 vs. 9.2 ± 2.4mmHg, p = 0.89) and dimension (1.90 ± 0.09 vs. 1.86 ± 0.12cm, p = 0.72), negative dP/dt (-2589 ± 691 vs. -3115 ± 866mmHg/s, p = 0.50) and cardiac output (436 ± 28 vs. 481 ± 59ml/kg/min, p = 0.26) were not affected by TLV initiation. Left ventricular relaxation time constant (tau) slightly increased from 21.5 ± 3.3 to 24.9 ± 3.7ms (p = 0.03). Mean arterial systemic (48 ± 6 vs. 53 ± 7mmHg, p = 0.38) and pulmonary pressures (31.3 ± 2.5 vs. 30.4 ± 2.3mmHg, p = 0.61) were stable. As expected, the inspiratory phase of liquid cycling exhibited a small but significant effect on most variables (i.e. central venous pressure +2.6 ± 0.5mmHg, p = 0.001; LVEDP +1.18 ± 0.12mmHg, p<0.001). Conclusions TLV was well tolerated in our neonatal lamb model of severe respiratory distress syndrome and had limited impact on left ventricle diastolic function when compared to conventional mechanical ventilation. © 2018 Sage et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. | |||||
BibTeX:
@article{Sage2018, author = {Sage, M. and Nadeau, M. and Forand-Choinière, C. and Mousseau, J. and Vandamme, J. and Berger, C. and Tremblay-Roy, J.-S. and Tissier, R. and Micheau, P. and Fortin-Pellerin, É.}, title = {Assessing the impacts of total liquid ventilation on left ventricular diastolic function in a model of neonatal respiratory distress syndrome}, journal = {PLoS ONE}, year = {2018}, volume = {13}, number = {1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041211592&doi=10.1371%2fjournal.pone.0191885&partnerID=40&md5=15744f6407733ee6dde1a0a9c6ac1e81}, doi = {https://doi.org/10.1371/journal.pone.0191885} } |
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Temporelli, R., Boisvert, M. and Micheau, P. | Accurate Clutch Slip Controllers during Vehicle Steady and Acceleration States | 2018 | IEEE/ASME Transactions on Mechatronics Vol. 23(5), pp. 2078-2089 |
article | DOI URL |
Abstract: Over the past years, the control of the clutch clamping force has been studied to guarantee a smooth/fast and low-wear engagement. Recent studies have highlighted the interest in controlling the clutch clamping force in order to limit vibrations in vehicle drivelines. However, the major risk with any clutch clamping control strategy is an unexpected clutch opening due to the ignorance of the nonlinear and time-varying relationship between clutch clamping and clutch slip. Inspite of improvements, an accurate clutch slip control currently remains a challenge due to high nonlinear dynamics, uncertain parameters, and noisy environments, which render the clutch slip control more complex. In line with this challenging premise, this study presents two accurate clutch slip controllers used during vehicle steady states (constant engine speed) and vehicle acceleration states (increasing engine speed). The first controller, based on punctual least square adaptations of a clutch slip relation, yielded accurate clutch slip tracking results only in the vehicle steady state. In contrast, the second controller, based on a nearly continuous least mean square adaptation of the clutch slip relationship in parallel with a proportional-integral compensator, yielded accurate clutch slip tracking results both in vehicle steady and acceleration states. © 1996-2012 IEEE. | |||||
BibTeX:
@article{Temporelli20182078, author = {Temporelli, R. and Boisvert, M. and Micheau, P.}, title = {Accurate Clutch Slip Controllers during Vehicle Steady and Acceleration States}, journal = {IEEE/ASME Transactions on Mechatronics}, year = {2018}, volume = {23}, number = {5}, pages = {2078-2089}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85052694395&doi=10.1109%2fTMECH.2018.2867281&partnerID=40&md5=635e48e1b46589aed464e10b5a93d1f5}, doi = {https://doi.org/10.1109/TMECH.2018.2867281} } |
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Verdiere, K., Atalla, N. and Panneton, R. | A Case Study of a Full Inverse Poroelastic Characterization of an Open-Cell Porous Material Using an Impedance Tube: The Need to Properly Prepare the Material and to Control the Measurement | 2018 | SAE Technical Papers Vol. 2018-June(June) |
article | DOI URL |
Abstract: This paper presents a case study on the full inverse characterization of the material properties of an open-cell poroelastic foam using impedance tube measurements. It aims to show the importance of controlling the lateral boundary condition in the impedance tube, and selecting an appropriate acoustic model to obtain the most accurate material properties. The case study uses a four-inch thick melamine foam and a 100-mm diameter tube. The foam is mechanically cut to fit within the circular tube. However, the cutting process is not perfect and a tiny lateral air gap exists between the material and the tube (i.e. the foam diameter is 99.5 mm for a 100-mm diameter tube). The typical characterization procedure is to mix direct and indirect measurements to retrieve the material properties of the foam. First, open porosity, bulk density, and static airflow resistivity are directly measured. Second, tortuosity, viscous and thermal characteristic lengths, and elastic properties are identified by inverse characterization using impedance tube measurements. The inverse characterization uses different choices of frame behavior models (rigid, limp, or elastic), and lateral boundary conditions (with and without lateral air gap). The paper discusses the effects of the choice of the frame behavior model and lateral boundary condition. Notably, it shows that the tiny air gap can seriously affect the inversely characterized material properties. Moreover, the choice of the frame model impacts less the quality of the inversion, but allows or not the characterization of the elastic properties. Finally, the paper concludes with recommendations and guidelines to improve the accuracy of the inverse characterization procedure, and discusses its limitations. © 2018 SAE International. All Rights Reserved. | |||||
BibTeX:
@article{Verdiere2018, author = {Verdiere, K. and Atalla, N. and Panneton, R.}, title = {A Case Study of a Full Inverse Poroelastic Characterization of an Open-Cell Porous Material Using an Impedance Tube: The Need to Properly Prepare the Material and to Control the Measurement}, journal = {SAE Technical Papers}, year = {2018}, volume = {2018-June}, number = {June}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050521678&doi=10.4271%2f2018-01-1567&partnerID=40&md5=d5697833ab8e8bc53b851b2b0056f9da}, doi = {https://doi.org/10.4271/2018-01-1567} } |
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Abbad, A., Rabenorosoa, K., Ouisse, M. and Atalla, N. | Investigations on an electroactive polymer based tunable Helmholtz resonator | 2017 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 10164 |
conference | DOI URL |
Abstract: A Helmholtz resonator is a passive acoustic resonator classically used to control a single frequency resulting from the cavity volume and the resonator neck size. The aim of the proposed study is to present a new concept and strategy allowing real-time tunability of the Helmholtz resonator in order to enhance acoustic absorption performances at low frequencies (< 500 Hz). The proposed concept consists in replacing the resonator rigid front plate by an electroactive polymer (EAP) membrane. The first proposed strategy consists on a change in the mechanical properties of the membrane resulting from the applied electric field. This induces a resonance frequency shift. A second strategy is based on a well-located spring, which could direct the membrane deformation following the axis of the resonator to obtain a cavity volume variation. Both strategies allow variation of the resonance frequency of the device. Experimental measurements are performed to determine the potential of this concept for improvement of low-frequency performances of the acoustic devices. © 2017 SPIE. | |||||
BibTeX:
@conference{Abbad2017, author = {Abbad, A. and Rabenorosoa, K. and Ouisse, M. and Atalla, N.}, title = {Investigations on an electroactive polymer based tunable Helmholtz resonator}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2017}, volume = {10164}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85024093751&doi=10.1117%2f12.2259883&partnerID=40&md5=0630a58e5bfd14552f6d2687efc927ce}, doi = {https://doi.org/10.1117/12.2259883} } |
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Alimonti, L. and Atalla, N. | Efficient modeling of flat and homogeneous acoustic treatments for vibroacoustic finite element analysis. Finite size correction by image sources | 2017 | Journal of Sound and Vibration Vol. 388, pp. 201-215 |
article | DOI URL |
Abstract: This work is concerned with the hybrid finite element-transfer matrix methodology recently proposed by the authors. The main assumption behind this hybrid method consists in neglecting the actual finite lateral extent of the acoustic treatment. Although a substantial increase of the computational efficiency can be achieved, the effect of the reflected field (i.e. finite size effects) may be sometimes important, preventing the hybrid model from giving quantitative meaningful results. For this reason, a correction to account for wave reflections at the lateral boundaries of the acoustic treatment is sought. It is shown in the present paper that the image source method can be successfully employed to retrieve such finite size effects. Indeed, such methodology is known to be effective when the response of the system is a smooth function of the frequency, like in the case of highly dissipative acoustic treatments. The main concern of this paper is to assess accuracy and feasibility of the image source method in the context of acoustic treatments modeling. Numerical examples show that the performance of the standard hybrid model can be substantially improved by the proposed correction without deteriorating excessively the computational efficiency. © 2016 Elsevier Ltd | |||||
BibTeX:
@article{Alimonti2017201, author = {Alimonti, L. and Atalla, N.}, title = {Efficient modeling of flat and homogeneous acoustic treatments for vibroacoustic finite element analysis. Finite size correction by image sources}, journal = {Journal of Sound and Vibration}, year = {2017}, volume = {388}, pages = {201-215}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84997336171&doi=10.1016%2fj.jsv.2016.10.028&partnerID=40&md5=bd1e2c66792ec706506b824b27476bc0}, doi = {https://doi.org/10.1016/j.jsv.2016.10.028} } |
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Berry, A., Robin, O. and O’Donoughue, P. | Identifying dynamic constitutive parameters of bending plates using the virtual fields method | 2017 | Conference Proceedings of the Society for Experimental Mechanics Series(200869), pp. 5-8 | conference | DOI URL |
Abstract: The identification and mapping of dynamic structural or material parameters is of interest in vibration and acoustic studies. Especially, there is a need for fast, non-destructive and possibly in-situ methods for extracting such parameters. This work investigates the mapping of local bending stiffness and structural loss factor of thin panels using full-field vibration response measurements and the Virtual Fields Method (VFM). VFM is based on an integral form of the dynamic equilibrium. Piecewise virtual displacement functions defined on a small region scanning the whole panel are used to extract the constitutive parameters of the structure. For bending plates, the method requires measuring both the transverse displacement field and bending curvature fields. This is achieved using either scanning Doppler laser vibrometry or full-field optical deflectometry and appropriate spatial finite difference calculations. The presentation will detail the VFM formulation and the experimental, full-field measurement techniques used for this problem. Examples of results will be shown for isotropic (metallic) and orthotropic (composite) panels excited at specific frequencies. In the latter case, the structural parameters agree with those obtained from ASTM standard tests. © The Society for Experimental Mechanics, Inc. 2017. | |||||
BibTeX:
@conference{Berry20175, author = {Berry, A. and Robin, O. and O’Donoughue, P.}, title = {Identifying dynamic constitutive parameters of bending plates using the virtual fields method}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2017}, number = {200869}, pages = {5-8}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85032494985&doi=10.1007%2f978-3-319-51439-0_2&partnerID=40&md5=2ddbf70657ade0451d020dd94b8f4715}, doi = {https://doi.org/10.1007/978-3-319-51439-0_2} } |
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Bilodeau, M., Quaegebeur, N. and Masson, P. | Design of a guided wave absorber for Structural Health Monitoring system development | 2017 | NDT and E International Vol. 88, pp. 33-41 |
article | DOI URL |
Abstract: The objective of this paper is to present and validate an efficient guided wave absorber for increased sensitivity of structural health monitoring systems based on guided wave, and especially for inspection close to structure boundaries. Such an absorber would also help with systematic characterization of guided waves interaction with defects in aerospace structures. A complete numerical parametric study is undertaken using the power flow in the structure to determine the reflection and transmission coefficients and thus the dissipated energy by the absorber. Starting with the determination of the geometry and dimensions using Finite Element Modelling (FEM), and following with an investigation on the influence of the absorber's mechanical properties, a practical and efficient absorber is identified. The dimensions of the developed absorber are minimized to provide optimal results for frequencies ranging from 50 kHz to 500 kHz for an incident A0mode. The resulting right triangle cross section absorber of Teflon has been machined and tested experimentally using a piezoelectric wave generator on one side of the absorber, and a tri-dimensional laser Doppler vibrometer (3D-LDV) to measure the transmitted wave on the other side. Using a spatial Fourier transform approach for the determination of the experimental reflection and transmission coefficients, the numerical results have been successfully validated. © 2017 Elsevier Ltd | |||||
BibTeX:
@article{Bilodeau201733, author = {Bilodeau, M. and Quaegebeur, N. and Masson, P.}, title = {Design of a guided wave absorber for Structural Health Monitoring system development}, journal = {NDT and E International}, year = {2017}, volume = {88}, pages = {33-41}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014911823&doi=10.1016%2fj.ndteint.2017.03.003&partnerID=40&md5=e219fcb3aa62eb06df93ad15628ca8b8}, doi = {https://doi.org/10.1016/j.ndteint.2017.03.003} } |
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Bolduc, A., Gauthier, P.-A. and Berry, A. | Auralization of vibroacoustic models in engineering using Wave Field Synthesis: Application to plates and transmission loss | 2017 | Journal of Sound and Vibration Vol. 410, pp. 64-86 |
article | DOI URL |
Abstract: While perceptual evaluation and sound quality testing with jury are now recognized as essential parts of acoustical product development, they are rarely implemented with spatial sound field reproduction. Instead, monophonic, stereophonic or binaural presentations are used. This paper investigates the workability and interest of a method to use complete vibroacoustic engineering models for auralization based on 2.5D Wave Field Synthesis (WFS). This method is proposed in order that spatial characteristics such as directivity patterns and direction-of-arrival are part of the reproduced sound field while preserving the model complete formulation that coherently combines frequency and spatial responses. Modifications to the standard 2.5D WFS operators are proposed for extended primary sources, affecting the reference line definition and compensating for out-of-plane elementary primary sources. Reported simulations and experiments of reproductions of two physically-accurate vibroacoustic models of thin plates show that the proposed method allows for an effective reproduction in the horizontal plane: Spatial and frequency domains features are recreated. Application of the method to the sound rendering of a virtual transmission loss measurement setup shows the potential of the method for use in virtual acoustical prototyping for jury testing. © 2017 Elsevier Ltd | |||||
BibTeX:
@article{Bolduc201764, author = {Bolduc, A. and Gauthier, P.-A. and Berry, A.}, title = {Auralization of vibroacoustic models in engineering using Wave Field Synthesis: Application to plates and transmission loss}, journal = {Journal of Sound and Vibration}, year = {2017}, volume = {410}, pages = {64-86}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85036624990&doi=10.1016%2fj.jsv.2017.08.025&partnerID=40&md5=73a2bcaca8557c1e462c5e2a94f74d3b}, doi = {https://doi.org/10.1016/j.jsv.2017.08.025} } |
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Cherif, R., Wareing, A. and Atalla, N. | Evaluation of a hybrid TMM-SEA method for prediction of sound transmission loss through mechanically coupled aircraft double-walls | 2017 | Applied Acoustics Vol. 117, pp. 132-140 |
article | DOI URL |
Abstract: This paper presents a detailed experimental validation of a hybrid TMM (transfer matrix method)/SEA (statistical energy analysis) method to predict the sound transmission through mechanically coupled aircraft double-walls. The accuracy of the model is investigated using lightweight structures representative of a composite aircraft fuselage cross-section over a large frequency band. The studied structure is composed of a thick composite sandwich panel representative of primary structure, lined with an acoustic insulation layer (glass wool), and structurally connected via vibration isolators to a thin composite sandwich lining panel representative of an interior trim panel. Three types of vibration isolators are considered: a soft, stiff and rigid mechanical links. Results show that the transfer matrix model is able to predict changes in the overall transmission caused by different structural couplings. Modelling limitation is mainly traced to the uncertainties in the measurement of the dynamic stiffness of vibration isolators which are directly propagated to the coupling loss factor and, therefore, to the transmission loss. © 2016 Elsevier Ltd | |||||
BibTeX:
@article{Cherif2017132, author = {Cherif, R. and Wareing, A. and Atalla, N.}, title = {Evaluation of a hybrid TMM-SEA method for prediction of sound transmission loss through mechanically coupled aircraft double-walls}, journal = {Applied Acoustics}, year = {2017}, volume = {117}, pages = {132-140}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84997417488&doi=10.1016%2fj.apacoust.2016.11.002&partnerID=40&md5=2a562789e25739213968a8c52d7b2a7c}, doi = {https://doi.org/10.1016/j.apacoust.2016.11.002} } |
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Gauthier, P.-A., Grandjean, P. and Berry, A. | Investigation of the group lasso algorithm for sound field reproduction: Comparison with the lasso and elastic-net algorithms | 2017 | 24th International Congress on Sound and Vibration, ICSV 2017 | conference | URL |
Abstract: The reproduction of a sound field measured using a microphone array is an active topic of research. To this end, loudspeaker and microphone arrays are used. Classical methods rely on spatial transforms (such as spherical Fourier transform for Ambisonics) or pressure matching using least-mean-square formulation. For both methods, all the reproduction sources (i.e. loudspeakers) will typically be activated. Although this can provide a reduced or minimized reproduction error evaluated at the microphone array, it is not necessarily the most useful solution for listening purposes. Indeed, the fact that all reproduction sources are concurrently active can potentially lead to a blurry spatial image (an example would be the common front-back confusion). To solve that potential limitation, the lasso and elastic-net algorithms were recently studied in order to favor the sparsity of the reproduction source signals. In these studies, it was shown that sparsity can indeed lead to a sharper source distribution at the cost of reduced physical accuracy of the reproduced sound field. In this paper, the group lasso is investigated to alleviate such potential limitations of the lasso, where the "group" refer to groups of reproduction sources. The aim of the group lasso is to provide sparsity at the group level and continuous smooth solution inside groups. In the recent literature, many simple or detailed algorithms have been proposed for the real-valued group lasso without a consensual position from the community. For sound field reproduction, a simple algorithmic implementation is proposed as an interpretation of the group lasso for complex quantities. Simulation results in free field show that several of the limitations of the lasso and elastic-net algorithms are solved. Potentials and current limitations of the group lasso are discussed. Based on the reported investigation, future research openings include: the possibility of overlapping groups and the algorithmic implementation. | |||||
BibTeX:
@conference{Gauthier2017, author = {Gauthier, P.-A. and Grandjean, P. and Berry, A.}, title = {Investigation of the group lasso algorithm for sound field reproduction: Comparison with the lasso and elastic-net algorithms}, journal = {24th International Congress on Sound and Vibration, ICSV 2017}, year = {2017}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029422972&partnerID=40&md5=2882ed7d84d714720f66e6e53bb189d9} } |
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Gauthier, P.-A., Scullion, W. and Berry, A. | Sound quality prediction based on systematic metric selection and shrinkage: Comparison of stepwise, lasso, and elastic-net algorithms and clustering preprocessing | 2017 | Journal of Sound and Vibration Vol. 400, pp. 134-153 |
article | DOI URL |
Abstract: Sound quality is the impression of quality that is transmitted by the sound of a device. Its importance in sound and acoustical design of consumer products no longer needs to be demonstrated. One of the challenges is the creation of a prediction model that is able to predict the results of a listening test while using metrics derived from the sound stimuli. Often, these models are either derived using linear regression on a limited set of experimenter-selected metrics, or using more complex algorithms such as neural networks. In the former case, the user-selected metrics can bias the model and reflect the engineer pre-conceived idea of sound quality while missing potential features. In the latter case, although prediction might be efficient, the model is often in the form of a black-box which is difficult to use as a sound design guideline for engineers. In this paper, preprocessing by participants clustering and three different algorithms are compared in order to construct a sound quality prediction model that does not suffer from these limitations. The lasso, elastic-net and stepwise algorithms are tested for listening tests of consumer product for which 91 metrics are used as potential predictors. Based on the reported results, it is shown that the most promising algorithm is the lasso which is able to (1) efficiently limit the number of metrics, (2) most accurately predict the results of listening tests, and (3) provide a meaningful model that can be used as understandable design guidelines. © 2017 Elsevier Ltd | |||||
BibTeX:
@article{Gauthier2017134, author = {Gauthier, P.-A. and Scullion, W. and Berry, A.}, title = {Sound quality prediction based on systematic metric selection and shrinkage: Comparison of stepwise, lasso, and elastic-net algorithms and clustering preprocessing}, journal = {Journal of Sound and Vibration}, year = {2017}, volume = {400}, pages = {134-153}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019263394&doi=10.1016%2fj.jsv.2017.03.025&partnerID=40&md5=424d8544e69e28e46feebd49a9e9e81c}, doi = {https://doi.org/10.1016/j.jsv.2017.03.025} } |
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Gauthier, P.-A., Lecomte, P. and Berry, A. | Source sparsity control of sound field reproduction using the elastic-net and the lasso minimizers | 2017 | Journal of the Acoustical Society of America Vol. 141(4), pp. 2315-2326 |
article | DOI URL |
Abstract: Sound field reproduction is aimed at the reconstruction of a sound pressure field in an extended area using dense loudspeaker arrays. In some circumstances, sound field reproduction is targeted at the reproduction of a sound field captured using microphone arrays. Although methods and algorithms already exist to convert microphone array recordings to loudspeaker array signals, one remaining research question is how to control the spatial sparsity in the resulting loudspeaker array signals and what would be the resulting practical advantages. Sparsity is an interesting feature for spatial audio since it can drastically reduce the number of concurrently active reproduction sources and, therefore, increase the spatial contrast of the solution at the expense of a difference between the target and reproduced sound fields. In this paper, the application of the elastic-net cost function to sound field reproduction is compared to the lasso cost function. It is shown that the elastic-net can induce solution sparsity and overcomes limitations of the lasso: The elastic-net solves the non-uniqueness of the lasso solution, induces source clustering in the sparse solution, and provides a smoother solution within the activated source clusters. © 2017 Acoustical Society of America. | |||||
BibTeX:
@article{Gauthier20172315, author = {Gauthier, P.-A. and Lecomte, P. and Berry, A.}, title = {Source sparsity control of sound field reproduction using the elastic-net and the lasso minimizers}, journal = {Journal of the Acoustical Society of America}, year = {2017}, volume = {141}, number = {4}, pages = {2315-2326}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85016950358&doi=10.1121%2f1.4979260&partnerID=40&md5=6ce210e3ab2c369b97552c2b17b97a43}, doi = {https://doi.org/10.1121/1.4979260} } |
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Gholami, M., Doutres, O. and Atalla, N. | Effect of microstructure closed-pore content on the mechanical properties of flexible polyurethane foam | 2017 | International Journal of Solids and Structures Vol. 112, pp. 97-105 |
article | DOI URL |
Abstract: Poroelastic models are constructed based on a set of physical parameters known as the Biot's parameters (for isotropic materials these are comprised of 5 non-acoustical parameters and 4 mechanical parameters). These macroscopic properties are inter-correlated and dependent on the microstructure of the foam. Therefore, to optimize vibroacoustic behavior, the correlation between foam microstructure and macroscopic properties is needed. In this study, the effect of closed windows content (known as reticulation rate), cell size, and relative density on the mechanical properties of polyurethane (PU) foam are numerically studied using an isotropic, tetrakaidecahedral unit cell. Then, an existing analytical model that correlates unit cell microstructure properties (thickness and length of struts) of fully reticulated foams to their mechanical properties is extended numerically. The membrane thickness is considered to be thinner at the center and larger at the edge of the window. The ratio of membrane thickness to strut thickness is either considered to be fixed or variable. Results show that the Young's modulus and Poisson's ratio of unit cells with smaller cells size, when relative density is fixed, are more affected by closed window content. © 2017 Elsevier Ltd | |||||
BibTeX:
@article{Gholami201797, author = {Gholami, M.S. and Doutres, O. and Atalla, N.}, title = {Effect of microstructure closed-pore content on the mechanical properties of flexible polyurethane foam}, journal = {International Journal of Solids and Structures}, year = {2017}, volume = {112}, pages = {97-105}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014418315&doi=10.1016%2fj.ijsolstr.2017.02.016&partnerID=40&md5=506a005c46c99028ba4cd91463b62afa}, doi = {https://doi.org/10.1016/j.ijsolstr.2017.02.016} } |
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Laly, Z., Atalla, N. and Meslioui, S.-A. | Characterization of micro-perforated panel at high sound pressure levels using rigid frame porous models | 2017 | Proceedings of Meetings on Acoustics Vol. 30(1) |
conference | DOI URL |
Abstract: An acoustic impedance model to predict the acoustic response of micro-perforated panels at high sound pressure levels is proposed using rigid frame porous models. The micro-perforated panel is modeled following Johnson-Allard approach with an effective density which depends on the frequency. The incident sound pressure on the surface of the perforations is considered as a main variable in the model and the parameters of the equivalent fluid such as the tortuosity and the flow resistivity are expressed as functions of this incidence pressure. The proposed model shows good agreement by comparison with other existing nonlinear impedance models for sound pressure level up to 150 dB. Experimental measurements were performed on several micro-perforated panels backed by air cavities using an impedance tube equipped with a high sound speaker capable of delivering a high sound pressure level up to 155 dB. A good correlation between theoretical and experimental results is obtained. Micro-perforated panel backed by porous material is modeled and validated experimentally using an equivalent tortuosity of the micro-perforated panel which depends on the dynamic tortuosity of the porous layer. © 2017 Acoustical Society of America. | |||||
BibTeX:
@conference{Laly2017, author = {Laly, Z. and Atalla, N. and Meslioui, S.-A.}, title = {Characterization of micro-perforated panel at high sound pressure levels using rigid frame porous models}, journal = {Proceedings of Meetings on Acoustics}, year = {2017}, volume = {30}, number = {1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85049419909&doi=10.1121%2f2.0000599&partnerID=40&md5=91151c4ba983ce6ade505db9aab37e10}, doi = {https://doi.org/10.1121/2.0000599} } |
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Leclaire, P., Lardeau, A., Dupont, T., Geslain, A., Panneton, R., Brooke, D. and Umnova, O. | Recent developments in the acoustical properties of perforated and porous materials containing dead-end pores - Applications to low frequency sound absorption | 2017 | 24th International Congress on Sound and Vibration, ICSV 2017 | conference | URL |
Abstract: It was shown recently in Nevers, France, Sherbrooke, Canada and Salford, UK, that porous materials with semi-opened pores or materials with open pores bearing lateral cavities or resonators at the microscopic scale of the pores can result in peculiar sound absorption properties. Various examples of these materials can be found in engineering and in everyday life including bio-based materials. The cavities and resonators can be assimilated to dead-end pores, which are opened at one end and closed at the other. The deadend pores are known to geophysicists. We studied them more recently in the field of engineering acoustics where the saturating fluid is air. The closed ends prevent the fluid to flow in the dead-end pores so that a crucial assumption usually made in the classical models of the acoustics of porous media based on Biot's theory is not fulfilled for these materials. In some dead-end pore materials, it was observed that the frequency of the absorption peak was lowered and that the absorption was increased. This has led to the development of new materials with controlled microstructure for low frequency sound absorption applications. Perforated materials with dead-ends were designed and built and their low frequency performances were confirmed experimentally. Absorption peaks around 0.9 were measured at a few hundred Hz for materials of a few centimeters thickness. Future developments of dead-end pore materials are concerned with the optimization of the microstructure, new designs of the microstructure, the use of dead-end pore materials in muffler applications, the interaction with the black hole effect, the behavior under high sound level and the use of vibroacoustic properties of perforated plates for low frequency sound absorption. | |||||
BibTeX:
@conference{Leclaire2017, author = {Leclaire, P. and Lardeau, A. and Dupont, T. and Geslain, A. and Panneton, R. and Brooke, D. and Umnova, O.}, title = {Recent developments in the acoustical properties of perforated and porous materials containing dead-end pores - Applications to low frequency sound absorption}, journal = {24th International Congress on Sound and Vibration, ICSV 2017}, year = {2017}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029450552&partnerID=40&md5=f97393d306608d73598d41b7c05031e1} } |
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Leclaire, P., Umnova, O., Dupont, T. and Panneton, R. | Low frequency and nonlinear acoustical behaviour of plates with perforations bearing periodically spaced flat resonators [BibTeX] |
2017 | 13th International Conference on Theoretical and Computational Acoustics, ICTCA 2017 Vol. 2017-July, pp. 72 |
conference | URL |
BibTeX:
@conference{Leclaire201772, author = {Leclaire, P. and Umnova, O. and Dupont, T. and Panneton, R.}, title = {Low frequency and nonlinear acoustical behaviour of plates with perforations bearing periodically spaced flat resonators}, journal = {13th International Conference on Theoretical and Computational Acoustics, ICTCA 2017}, year = {2017}, volume = {2017-July}, pages = {72}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047319679&partnerID=40&md5=c1d79ce673f21de9c5f9cbeb71f3a8e8} } |
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Luu, H., Perrot, C. and Panneton, R. | Influence of porosity, fiber radius and fiber orientation on the transport and acoustic properties of random fiber structures | 2017 | Acta Acustica united with Acustica Vol. 103(6), pp. 1050-1063 |
article | DOI URL |
Abstract: The ability of air-saturated fibrous media to mitigate sound waves is controlled by their transport properties that are themselves controlled by the geometrical characteristics of their microstructure such as the open porosity, fiber radius, and fiber orientation. Here, micro-macro relationships are proposed to link these microstructural features to the macroscopic transport properties of random fiber structures. These transport properties are the tortuosity, the viscous and thermal static permeabilities, and the viscous and thermal characteristic lengths. First, representative elementary volumes (REVs) of random fiber structures are generated for different triplets of porosity, fiber radius and fiber orientation. The fibers are allowed to overlap and are motionless (rigid-frame assumption). The fiber orientation is derived from a second order orientation tensor. Second, the transport equations are numerically solved on the REVs which are seen as periodic unit cells. These solutions yield the transport properties governing the sound propagation and dissipation in the respective fibrous media. From these solutions, micromacro relationships are derived to estimate the transport properties when the geometry of the fiber structure is known. Finally, these relationships are used to study the influence of the microstructural features on the acoustic properties of random fiber structures. © 2017 S. Hirzel Verlag. | |||||
BibTeX:
@article{Luu20171050, author = {Luu, H.T. and Perrot, C. and Panneton, R.}, title = {Influence of porosity, fiber radius and fiber orientation on the transport and acoustic properties of random fiber structures}, journal = {Acta Acustica united with Acustica}, year = {2017}, volume = {103}, number = {6}, pages = {1050-1063}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85034041755&doi=10.3813%2fAAA.919134&partnerID=40&md5=79fe6f0ca98da743b7f98162c12aa7e1}, doi = {https://doi.org/10.3813/AAA.919134} } |
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Luu, H., Perrot, C., Monchiet, V. and Panneton, R. | Three-dimensional reconstruction of a random fibrous medium: Geometry, transport, and sound absorbing properties | 2017 | Journal of the Acoustical Society of America Vol. 141(6), pp. 4768-4780 |
article | DOI URL |
Abstract: The main purpose of this article is to present, within a unified framework, a technique based on numerical homogenization, to model the acoustical properties of real fibrous media from their geometrical characteristics and to compare numerical results with experimental data. The authors introduce a reconstruction procedure for a random fibrous medium and use it as a basis for the computation of its geometrical, transport, and sound absorbing properties. The previously ad hoc "fiber anisotropies" and "volume weighted average radii," used to describe the experimental data on microstructure, are here measured using scanning electron microscopy. The authors show that these parameters, in conjunction with the bulk porosity, contribute to a precise description of the acoustical characteristics of fibrous absorbents. They also lead to an accurate prediction of transport parameters which can be used to predict acoustical properties. The computed values of the permeability and frequency-dependent sound absorption coefficient are successfully compared with permeability and impedance-tube measurements. The authors' results indicate the important effect of fiber orientation on flow properties associated with the different physical properties of fibrous materials. A direct link is provided between three-dimensional microstructure and the sound absorbing properties of non-woven fibrous materials, without the need for any empirical formulae or fitting parameters. © 2017 Acoustical Society of America. | |||||
BibTeX:
@article{Luu20174768, author = {Luu, H.T. and Perrot, C. and Monchiet, V. and Panneton, R.}, title = {Three-dimensional reconstruction of a random fibrous medium: Geometry, transport, and sound absorbing properties}, journal = {Journal of the Acoustical Society of America}, year = {2017}, volume = {141}, number = {6}, pages = {4768-4780}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85021394635&doi=10.1121%2f1.4989373&partnerID=40&md5=ebfe1875a030413479814095a7d6a8fc}, doi = {https://doi.org/10.1121/1.4989373} } |
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Luu, H., Panneton, R. and Perrot, C. | Effective fiber diameter for modeling the acoustic properties of polydisperse fiber networks | 2017 | Journal of the Acoustical Society of America Vol. 141(2), pp. EL96-EL101 |
article | DOI URL |
Abstract: The purpose of this research is to determine whether the acoustic properties of polydisperse fibrous medium (PDFM) and bidisperse fibrous medium (BDFM) can be modeled by monodisperse fiber media (MDFM) with an effective fiber diameter. Multi-scale numerical simulations on representative elementary volumes of these media are performed to retrieve the transport and geometrical properties governing their acoustic properties. Results show no significant difference between predictions obtained by PDFM or BDFM, and their corresponding effective MDFM. © 2017 Acoustical Society of America. | |||||
BibTeX:
@article{Luu2017EL96, author = {Luu, H.T. and Panneton, R. and Perrot, C.}, title = {Effective fiber diameter for modeling the acoustic properties of polydisperse fiber networks}, journal = {Journal of the Acoustical Society of America}, year = {2017}, volume = {141}, number = {2}, pages = {EL96-EL101}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85012928664&doi=10.1121%2f1.4976114&partnerID=40&md5=64c014e26c9a8b9a735171e0b88af103}, doi = {https://doi.org/10.1121/1.4976114} } |
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Marchetto, C., Maxit, L., Robin, O. and Berry, A. | Vibroacoustic response of panels under diffuse acoustic field excitation from sensitivity functions and reciprocity principles | 2017 | Journal of the Acoustical Society of America Vol. 141(6), pp. 4508-4521 |
article | DOI URL |
Abstract: This paper aims at developing an experimental method to characterize the vibroacoustic response of a panel to a diffuse acoustic field (DAF) excitation with a different laboratory setup than those used in standards (i.e., coupled rooms). The proposed methodology is based on a theoretical model of the DAF and on the measurement of the panel's sensitivity functions, which characterize its vibroacoustic response to wall plane waves. These functions can be estimated experimentally using variations of the reciprocity principle, which are described in the present paper. These principles can either be applied for characterizing the structural response by exciting the panel with a normal force at the point of interest or for characterizing the acoustic response (radiated pressure, acoustic intensity) by exciting the panel with a monopole and a dipole source. For both applications, the validity of the proposed approach is numerically and experimentally verified on a test case composed of a baffled simply supported plate. An implementation for estimating the sound transmission loss of the plate is finally proposed. The results are discussed and compared with measurements performed in a coupled anechoic-reverberant room facility following standards. © 2017 Acoustical Society of America. | |||||
BibTeX:
@article{Marchetto20174508, author = {Marchetto, C. and Maxit, L. and Robin, O. and Berry, A.}, title = {Vibroacoustic response of panels under diffuse acoustic field excitation from sensitivity functions and reciprocity principles}, journal = {Journal of the Acoustical Society of America}, year = {2017}, volume = {141}, number = {6}, pages = {4508-4521}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020505855&doi=10.1121%2f1.4985126&partnerID=40&md5=c00214c1924b593878eb9e9241baaf33}, doi = {https://doi.org/10.1121/1.4985126} } |
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Micheau, P., Nadeau, M., Tissier, R. and Walti, H. | Direct Optimal Control of Breathable Liquid Temperature for Human Cooling | 2017 | IFAC-PapersOnLine Vol. 50(1), pp. 11017-11022 |
article | DOI URL |
Abstract: Ultrafast body cooling of mammals can be achieved by ventilating the lung with a breathable liquid during total liquid ventilation. The instilled liquid into the lung allows to cool the arterial blood temperature, and consequently the organs. While total liquid ventilation can rapidly cool animals, the speed of cooling in humans remains unknown. The problem is to predict the efficiency and safety of the method for humans. The method is based on a previously published mathematical thermal model of mammals in total liquid ventilation. The thermal model is projected to humans. A direct optimal control under constraints is computed to predict the hypothermia induction speed and the sensitivity to parametric uncertainties. The simulated results in human adults illustrate that a worst case optimal control can be used to compute a robust solution in regards to uncertainties of cardiac output and thermal dead volume. In certain patients, brain temperature would reach mild hypothermia in maximum 10 min, with the majority of patients reaching it within 6 min. Hence, the direct optimal control is a potential candidate for the ultrafast therapeutic hypothermia induction for cardio- and neuroprotection of post-cardiac arrest patients. © 2017 | |||||
BibTeX:
@article{Micheau201711017, author = {Micheau, P. and Nadeau, M. and Tissier, R. and Walti, H.}, title = {Direct Optimal Control of Breathable Liquid Temperature for Human Cooling}, journal = {IFAC-PapersOnLine}, year = {2017}, volume = {50}, number = {1}, pages = {11017-11022}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85031783026&doi=10.1016%2fj.ifacol.2017.08.2481&partnerID=40&md5=c360621ffd4bc0c6db582dd43e2fd9f5}, doi = {https://doi.org/10.1016/j.ifacol.2017.08.2481} } |
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Moriot, J., Quaegebeur, N., Le Duff, A. and Masson, P. | Model-assisted assessment of damage detection and localization using guided wave-based imaging techniques | 2017 | Structural Health Monitoring 2017: Real-Time Material State Awareness and Data-Driven Safety Assurance - Proceedings of the 11th International Workshop on Structural Health Monitoring, IWSHM 2017 Vol. 1, pp. 399-406 |
conference | URL |
Abstract: In this paper, a model-assisted approach is proposed for assessing the ability of guided wave (GW)-based Structural Health Monitoring (SHM) imaging techniques to detect and localize a damage on a structure. A damage identification metric (DIM) is determined from the damage index (DI) image produced by the SHM system when a damage is present on the structure. Several damage sizes and positions are considered, thus producing various values of the DIM. The probability of detection (POD) curve is then calculated using the ß vs. a approach well established in the nondestructive testing (NDT) community. For assessing the localization performance of the system, the probability of localization (POL) curve is derived from the ratio of defects correctly localized to the total number of defects, based on the calculation of the absolute error of localization (AEL). The approach is applied for assessing the performance of an actual SHM system composed of three piezoelectric actuators bonded on an aluminum plate. A good agreement is observed between POD and POL curves obtained experimentally and using a finite element model (FEM) of the system. The model-assisted approach is finally used to predict the performance of the system assuming a variation of temperature between the baseline acquisition and the detection test. | |||||
BibTeX:
@conference{Moriot2017399, author = {Moriot, J. and Quaegebeur, N. and Le Duff, A. and Masson, P.}, title = {Model-assisted assessment of damage detection and localization using guided wave-based imaging techniques}, journal = {Structural Health Monitoring 2017: Real-Time Material State Awareness and Data-Driven Safety Assurance - Proceedings of the 11th International Workshop on Structural Health Monitoring, IWSHM 2017}, year = {2017}, volume = {1}, pages = {399-406}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85032451828&partnerID=40&md5=b274c4a9f796a43956d7d6cb676f1557} } |
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Nadeau, J., Micheau, P. and Boisvert, M. | Ideal regenerative braking torque in collaboration with hydraulic brake system | 2017 | 2017 12th International Conference on Ecological Vehicles and Renewable Energies, EVER 2017 | conference | DOI URL |
Abstract: In the presented hybrid vehicle, the electric motor is used in collaboration with the hydraulic brake system to impose an ideal braking torque to the rear wheel. This, in order to recharge the battery. The first objective aims to recover the maximum kinetic energy available. To achieve this task, the electric motor is used until the reach of its torque limits while an additional hydraulic brake force is exerted at the rear wheel only when it is needed. The second objective aims to improve the brake efficiency by performing the tracking of the ideal brake force distribution. An original aspect of this paper is the proposal of a brake force distribution strategy between the front and rear axles which is based on the tracking of the ideal brake torque (I-curve). The experimental results obtained with a recreational three-wheel electric vehicle validates the implementation of the proposed ideal collaborative braking control strategy. © 2017 IEEE. | |||||
BibTeX:
@conference{Nadeau2017, author = {Nadeau, J. and Micheau, P. and Boisvert, M.}, title = {Ideal regenerative braking torque in collaboration with hydraulic brake system}, journal = {2017 12th International Conference on Ecological Vehicles and Renewable Energies, EVER 2017}, year = {2017}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85021341907&doi=10.1109%2fEVER.2017.7935934&partnerID=40&md5=f1b7985bc24845b0a943eea30ce45588}, doi = {https://doi.org/10.1109/EVER.2017.7935934} } |
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Nadeau, M., Sage, M., Kohlhauer, M., Mousseau, J., Vandamme, J., Fortin-Pellerin, E., Praud, J.-P., Tissier, R., Walti, H. and Micheau, P. | Optimal Control of Inspired Perfluorocarbon Temperature for Ultrafast Hypothermia Induction by Total Liquid Ventilation in an Adult Patient Model | 2017 | IEEE Transactions on Biomedical Engineering Vol. 64(12), pp. 2760-2770 |
article | DOI URL |
Abstract: Goal: Recent preclinical studies have shown that therapeutic hypothermia induced in less than 30 min by total liquid ventilation (TLV) strongly improves the survival rate after cardiac arrest. When the lung is ventilated with a breathable perfluorocarbon liquid, the inspired perfluorocarbon allows us to control efficiently the cooling process of the organs. While TLV can rapidly cool animals, the cooling speed in humans remains unknown. The objective is to predict the efficiency and safety of ultrafast cooling by TLV in adult humans. Methods: It is based on a previously published thermal model of ovines in TLV and the design of a direct optimal controller to compute the inspired perfluorocarbon temperature profile. The experimental results in an adult sheep are presented. The thermal model of sheep is subsequently projected to a human model to simulate the optimal hypothermia induction and its sensitivity to physiological parameter uncertainties. Results: The results in the sheep showed that the computed inspired perfluorocarbon temperature command can avoid arterial temperature undershoot. The projection to humans revealed that mild hypothermia should be ultrafast (reached in fewer than 3 min (-72 °C/h) for the brain and 20 min (-10 °C/h) for the entire body). Conclusion: The projection to human model allows concluding that therapeutic hypothermia induction by TLV can be ultrafast and safe. Significance: This study is the first to simulate ultrafast cooling by TLV in a human model and is a strong motivation to translate TLV to humans to improve the quality of life of postcardiac arrest patients. © 1964-2012 IEEE. | |||||
BibTeX:
@article{Nadeau20172760, author = {Nadeau, M. and Sage, M. and Kohlhauer, M. and Mousseau, J. and Vandamme, J. and Fortin-Pellerin, E. and Praud, J.-P. and Tissier, R. and Walti, H. and Micheau, P.}, title = {Optimal Control of Inspired Perfluorocarbon Temperature for Ultrafast Hypothermia Induction by Total Liquid Ventilation in an Adult Patient Model}, journal = {IEEE Transactions on Biomedical Engineering}, year = {2017}, volume = {64}, number = {12}, pages = {2760-2770}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040456327&doi=10.1109%2fTBME.2017.2671741&partnerID=40&md5=7fac7dcb60670b125e8851ae452433a2}, doi = {https://doi.org/10.1109/TBME.2017.2671741} } |
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Ostiguy, P.-C., Quaegebeur, N. and Masson, P. | Comparison of model-based damage imaging techniques for transversely isotropic composites | 2017 | Structural Health Monitoring Vol. 16(4), pp. 428-443 |
article | DOI URL |
Abstract: In order to reduce operation and maintenance costs of aircraft, in situ structural health monitoring techniques are implemented on critical parts and assemblies. Many of these techniques rely on models considering, with various levels of complexity, the generation, propagation and interaction of ultrasonic guided waves with potential damages, in order to detect, localize and estimate damage severity. Although their potential has been extensively demonstrated on isotropic substrates, their implementation still poses a challenge for composite assemblies for which only quasi-isotropic and cross-ply composites have been considered. This is mainly due to the limitations of the models to properly predict the complex behaviour of guided waves on composites, where the assumptions behind the models actually used for damage imaging do not fully consider the impact of the anisotropy on guided wave generation and propagation. This article presents a comparative analysis of the performances of three model-based damage imaging techniques for composites previously validated on isotropic substrates. The main objective of the study is to address the interest in using more complex analytical formulations to improve the performance of imaging techniques. This is obtained by comparing three imaging techniques, each presenting different levels of complexity in their numerical formulations. Performance of (a) delay-and-sum, (b) dispersion compensation and (c) correlation-based techniques are addressed numerically and experimentally. The analysis is conducted on a unidirectional transversely isotropic laminate instrumented with four circular piezoceramic transducers. A robustness analysis of the models is performed numerically, where the effect of varying stiffness parameters and velocity is addressed. The correlation-based technique is adapted for the first time to composite laminates where the generation is considered using the pin-force model and the propagation is modelled via the use of the global matrix model. Experimental validation is carried out and the results obtained show the benefit of considering the steering effect for well-resolved multi modal damage imaging. © 2016, © The Author(s) 2016. | |||||
BibTeX:
@article{Ostiguy2017428, author = {Ostiguy, P.-C. and Quaegebeur, N. and Masson, P.}, title = {Comparison of model-based damage imaging techniques for transversely isotropic composites}, journal = {Structural Health Monitoring}, year = {2017}, volume = {16}, number = {4}, pages = {428-443}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85023622137&doi=10.1177%2f1475921716674012&partnerID=40&md5=2e1f4f14c3ca485a8c581de0c4dc8d0e}, doi = {https://doi.org/10.1177/1475921716674012} } |
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Padois, T. and Berry, A. | Two and three-dimensional sound source localization with beamforming and several deconvolution techniques | 2017 | Acta Acustica united with Acustica Vol. 103(3), pp. 392-400 |
article | DOI URL |
Abstract: Microphone array associated to signal processing technique such as beamforming is an efficient tool to localize acoustic sources. In an open wind-tunnel, the microphone array can be set below, above or on the side of the flow. The microphones are spatially distributed over a two-dimensional (2D) plane and the geometry may be regular, circular or a spiral shape. For each case, the scan zone where the potential source positions are searched is a plane parallel to the microphone array. In this study, beamforming and several microphone array techniques (Clean-SC, L1-GIB, DAMAS and SC-DAMAS) are compared in the case of two and three-dimensional (3D) scan zones. The microphone array techniques are compared in terms of position detection, source level estimation and computation time. The cases of a 2D scan zone, either parallel or perpendicular to the microphone array, are investigated. Then, the performances of each technique are studied in the case of 3D scan zone with a single or two microphone arrays. SC-DAMAS provides the best noise source map at the expense of a large computation time if the number of scan point is large. Clean-SC is a good tradeoff between fast computation and correct source detection. The second microphone array improves the noise source map provided by L1-GIB with a reasonable computation time. © 2017 S. Hirzel Verlag EAA. | |||||
BibTeX:
@article{Padois2017392, author = {Padois, T. and Berry, A.}, title = {Two and three-dimensional sound source localization with beamforming and several deconvolution techniques}, journal = {Acta Acustica united with Acustica}, year = {2017}, volume = {103}, number = {3}, pages = {392-400}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020722454&doi=10.3813%2fAAA.919069&partnerID=40&md5=29516fab204001a2be8200ccfbf67d2a}, doi = {https://doi.org/10.3813/AAA.919069} } |
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Padois, T., Sgard, F., Doutres, O. and Berry, A. | Acoustic source localization using a polyhedral microphone array and an improved generalized cross-correlation technique | 2017 | Journal of Sound and Vibration Vol. 386, pp. 82-99 |
article | DOI URL |
Abstract: Millions of workers are exposed to excessive noise levels each day. Acoustic solutions have to be developed to protect workers from hearing loss. The first step of an acoustic diagnosis is the source localization which can be performed with a microphone array. Spherical microphone arrays can be used to detect the acoustic source positions in a workplace. In this study, a spherical microphone array, with polyhedral discretization, is proposed and compared with a spherical array with a slightly different geometry. The generalized cross-correlation technique is used to detect the source positions. Moreover, two criteria are introduced to improve the noise source map. The first is based on the geometric properties of the microphone array and the scan zone whereas the second is based on the energy of the spatial likelihood function. Numerical data are used to provide a systematic comparison of both geometries and criteria. Finally, experiments in a reverberant room reveal that the polyhedral microphone array associated with both criteria provides the best noise source map. © 2016 Elsevier Ltd | |||||
BibTeX:
@article{Padois201782, author = {Padois, T. and Sgard, F. and Doutres, O. and Berry, A.}, title = {Acoustic source localization using a polyhedral microphone array and an improved generalized cross-correlation technique}, journal = {Journal of Sound and Vibration}, year = {2017}, volume = {386}, pages = {82-99}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84992699688&doi=10.1016%2fj.jsv.2016.09.006&partnerID=40&md5=ddbe5c0aa60ace6191be6f6a0fc6c857}, doi = {https://doi.org/10.1016/j.jsv.2016.09.006} } |
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Padois, T., Doutres, O., Sgard, F. and Berry, A. | Time domain localization technique with sparsity constraint for imaging acoustic sources | 2017 | Mechanical Systems and Signal Processing Vol. 94, pp. 85-93 |
article | DOI URL |
Abstract: This paper addresses source localization technique in time domain for broadband acoustic sources. The objective is to accurately and quickly detect the position and amplitude of noise sources in workplaces in order to propose adequate noise control options and prevent workers hearing loss or safety risk. First, the generalized cross correlation associated with a spherical microphone array is used to generate an initial noise source map. Then a linear inverse problem is defined to improve this initial map. Commonly, the linear inverse problem is solved with an l2-regularization. In this study, two sparsity constraints are used to solve the inverse problem, the orthogonal matching pursuit and the truncated Newton interior-point method. Synthetic data are used to highlight the performances of the technique. High resolution imaging is achieved for various acoustic sources configurations. Moreover, the amplitudes of the acoustic sources are correctly estimated. A comparison of computation times shows that the technique is compatible with quasi real-time generation of noise source maps. Finally, the technique is tested with real data. © 2017 Elsevier Ltd | |||||
BibTeX:
@article{Padois201785, author = {Padois, T. and Doutres, O. and Sgard, F. and Berry, A.}, title = {Time domain localization technique with sparsity constraint for imaging acoustic sources}, journal = {Mechanical Systems and Signal Processing}, year = {2017}, volume = {94}, pages = {85-93}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85016588893&doi=10.1016%2fj.ymssp.2017.02.035&partnerID=40&md5=07731bd7997245e0a1514c35f84120c1}, doi = {https://doi.org/10.1016/j.ymssp.2017.02.035} } |
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Padois, T. and Berry, A. | Application of acoustic imaging techniques on snowmobile pass-by noise | 2017 | Journal of the Acoustical Society of America Vol. 141(2), pp. EL134-EL139 |
article | DOI URL |
Abstract: Snowmobile manufacturers invest important efforts to reduce the noise emission of their products. The noise sources of snowmobiles are multiple and closely spaced, leading to difficult source separation in practice. In this study, source imaging results for snowmobile pass-by noise are discussed. The experiments involve a 193-microphone Underbrink array, with synchronization of acoustic with video data provided by a high-speed camera. Both conventional beamforming and Clean-SC deconvolution are implemented to provide noise source maps of the snowmobile. The results clearly reveal noise emission from the engine, exhaust, and track depending on the frequency range considered. © 2017 Acoustical Society of America. | |||||
BibTeX:
@article{Padois2017EL134, author = {Padois, T. and Berry, A.}, title = {Application of acoustic imaging techniques on snowmobile pass-by noise}, journal = {Journal of the Acoustical Society of America}, year = {2017}, volume = {141}, number = {2}, pages = {EL134-EL139}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013187890&doi=10.1121%2f1.4976138&partnerID=40&md5=fed5bfddc44b40d013a2cabba9c9b303}, doi = {https://doi.org/10.1121/1.4976138} } |
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Pasco, Y., Gauthier, P.-A., Berry, A. and Moreau, S. | Interior sound field control using generalized singular value decomposition in the frequency domain | 2017 | Journal of the Acoustical Society of America Vol. 141(1), pp. 334-345 |
article | DOI URL |
Abstract: The problem of controlling a sound field inside a region surrounded by acoustic control sources is considered. Inspired by the Kirchhoff-Helmholtz integral, the use of double-layer source arrays allows such a control and avoids the modification of the external sound field by the control sources by the approximation of the sources as monopole and radial dipole transducers. However, the practical implementation of the Kirchhoff-Helmholtz integral in physical space leads to large numbers of control sources and error sensors along with excessive controller complexity in three dimensions. The present study investigates the potential of the Generalized Singular Value Decomposition (GSVD) to reduce the controller complexity and separate the effect of control sources on the interior and exterior sound fields, respectively. A proper truncation of the singular basis provided by the GSVD factorization is shown to lead to effective cancellation of the interior sound field at frequencies below the spatial Nyquist frequency of the control sources array while leaving the exterior sound field almost unchanged. Proofs of concept are provided through simulations achieved for interior problems by simulations in a free field scenario with circular arrays and in a reflective environment with square arrays. © 2017 Acoustical Society of America. | |||||
BibTeX:
@article{Pasco2017334, author = {Pasco, Y. and Gauthier, P.-A. and Berry, A. and Moreau, S.}, title = {Interior sound field control using generalized singular value decomposition in the frequency domain}, journal = {Journal of the Acoustical Society of America}, year = {2017}, volume = {141}, number = {1}, pages = {334-345}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85010021955&doi=10.1121%2f1.4973952&partnerID=40&md5=547c0646fed28eb2e62a3f13988a8e1a}, doi = {https://doi.org/10.1121/1.4973952} } |
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Perrier, S., Champoux, Y. and Drouet, J.-M. | The influence of a human hand-arm system on the vibrational dynamic behaviour of a compliant mechanical structure | 2017 | JVC/Journal of Vibration and Control Vol. 23(2), pp. 329-342 |
article | DOI URL |
Abstract: The aim of this study is to provide an approach to predicting human influence on a compliant mechanical structure using a substructuring technique. Substructuring techniques allow us to obtain detailed information on the vibrational behaviour of an assembly of structures by characterization of each structure separately. In this manuscript, a hand-arm system is coupled with a vibrating structure using a substructuring technique. A lightweight and compliant vibrating beam is used to demonstrate the concept. To demonstrate the feasibility of accurately predicting the hand-arm systems' influence on the beam, we selected one position and tested it using four push forces. The characteristics of the hand-arm system for each configuration were coupled with the dynamic characteristics of the beam only over a frequency range of [5; 300] Hz. For each of the four configurations, the coupling predicts the influence of the hand on the vibrational behaviour of the beam. Reliable predictions were obtained for the vibrational behaviour of the assembly. The results indicate that the substructuring approach predicted the vibrational behaviour of the hand-arm-beam assembly with less than 3% error. © SAGE Publications. | |||||
BibTeX:
@article{Perrier2017329, author = {Perrier, S.S. and Champoux, Y. and Drouet, J.-M.}, title = {The influence of a human hand-arm system on the vibrational dynamic behaviour of a compliant mechanical structure}, journal = {JVC/Journal of Vibration and Control}, year = {2017}, volume = {23}, number = {2}, pages = {329-342}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85008709583&doi=10.1177%2f1077546315577312&partnerID=40&md5=c19ce74c5005849630046f95a32e1fc3}, doi = {https://doi.org/10.1177/1077546315577312} } |
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Pompoli, F., Bonfiglio, P., Horoshenkov, K., Khan, A., Jaouen, L., Becot, F.-X., Sgard, F., Asdrubali, F., D’Alessandro, F., Hübelt, J., Atalla, N., Amédin, C., Lauriks, W. and Boeckx, L. | A round robin test of the acoustical properties of porous media | 2017 | INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet Vol. 2017-January |
conference | URL |
Abstract: There is a considerable number of research publications on the characterization of porous media that is carried out in accordance with the ISO 10534-2. However, the reproducibility of these characterization procedures is not well understood. This paper deals with the reproducibility of some standard characterization procedures for acoustic porous materials. One novelty of this paper is that independent laboratory measurements were performed on the same material specimens so that the naturally occurring inhomogeneity in materials was controlled. Another novelty of this work is that it presents the reproducibility data for the characteristic impedance, complex wavenumber and for some related pore structure properties. This work can be helpful to understand better the tolerances of these material characterization procedures so the improvements can be developed to reduce the experimental errors and improve the reproducibility between laboratories. © 2017 Institute of Noise Control Engineering. All Rights Reserved. | |||||
BibTeX:
@conference{Pompoli2017, author = {Pompoli, F. and Bonfiglio, P. and Horoshenkov, K. and Khan, A. and Jaouen, L. and Becot, F.-X. and Sgard, F. and Asdrubali, F. and D’Alessandro, F. and Hübelt, J. and Atalla, N. and Amédin, C. and Lauriks, W. and Boeckx, L.}, title = {A round robin test of the acoustical properties of porous media}, journal = {INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet}, year = {2017}, volume = {2017-January}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042047076&partnerID=40&md5=32db316b2a95f1c330cf9fedff207683} } |
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Pompoli, F., Bonfiglio, P., Horoshenkov, K., Khan, A., Jaouen, L., Bécot, F.-X., Sgard, F., Asdrubali, F., D'Alessandro, F., Hübelt, J., Atalla, N., Amédin, C., Lauriks, W. and Boeckx, L. | How reproducible is the acoustical characterization of porous media? | 2017 | Journal of the Acoustical Society of America Vol. 141(2), pp. 945-955 |
article | DOI URL |
Abstract: There is a considerable number of research publications on the characterization of porous media that is carried out in accordance with ISO 10534-2 (International Standards Organization, Geneva, Switzerland, 2001) and/or ISO 9053 (International Standards Organization, Geneva, Switzerland, 1991). According to the Web of ScienceTM (last accessed 22 September 2016) there were 339 publications in the Journal of the Acoustical Society of America alone which deal with the acoustics of porous media. However, the reproducibility of these characterization procedures is not well understood. This paper deals with the reproducibility of some standard characterization procedures for acoustic porous materials. The paper is an extension of the work published by Horoshenkov, Khan, Bécot, Jaouen, Sgard, Renault, Amirouche, Pompoli, Prodi, Bonfiglio, Pispola, Asdrubali, Hübelt, Atalla, Amédin, Lauriks, and Boeckx [J. Acoust. Soc. Am. 122(1), 345-353 (2007)]. In this paper, independent laboratory measurements were performed on the same material specimens so that the naturally occurring inhomogeneity in materials was controlled. It also presented the reproducibility data for the characteristic impedance, complex wavenumber, and for some related pore structure properties. This work can be helpful to better understand the tolerances of these material characterization procedures so improvements can be developed to reduce experimental errors and improve the reproducibility between laboratories. © 2017 Acoustical Society of America. | |||||
BibTeX:
@article{Pompoli2017945, author = {Pompoli, F. and Bonfiglio, P. and Horoshenkov, K.V. and Khan, A. and Jaouen, L. and Bécot, F.-X. and Sgard, F. and Asdrubali, F. and D'Alessandro, F. and Hübelt, J. and Atalla, N. and Amédin, C.K. and Lauriks, W. and Boeckx, L.}, title = {How reproducible is the acoustical characterization of porous media?}, journal = {Journal of the Acoustical Society of America}, year = {2017}, volume = {141}, number = {2}, pages = {945-955}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013404987&doi=10.1121%2f1.4976087&partnerID=40&md5=575ed43c01952eb00e46de7e89d79863}, doi = {https://doi.org/10.1121/1.4976087} } |
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Quaegebeur, N., Bouslama, N., Bilodeau, M., Masson, P., Maslouhi, A. and Micheau, P. | Guided wave scattering by a geometrical or damage feature: Application to fatigue crack and machined notch | 2017 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 10170 |
conference | DOI URL |
Abstract: Guided-wave based Non-Destructive Evaluation (NDE) and Structural Health Monitoring (SHM) systems validation under realistic conditions or environment requires complex setups. Numerical or theoretical approaches are useful to save time and cost associated with experimental tests but the interaction with realistic geometrical (rivets, thickness changes, stiffeners, extrusions) or damage features (fatigue cracks, fillet cracks, delaminations, disbonds) must be accurately captured in order to be representative. In this paper, an experimental methodology is presented for estimating the far-field scattering of geometrical or damage features. The principle is based on the use of a Hankel transform of the measured 3D velocity field in order to evaluate with precision the scattered pattern using a spatially averaged method. Application to scattering of a hole with simulated machined and real fatigue cracks is proposed. It is observed that the simulated machined crack generally used as a reference standard can only model accurately the transmission behaviour while the scattering patterns are only similar when the wavelength is about the size of the crack, limiting the practical use of machined cracks for experimental validation of SHM or NDE systems. © 2017 SPIE. | |||||
BibTeX:
@conference{Quaegebeur2017, author = {Quaegebeur, N. and Bouslama, N. and Bilodeau, M. and Masson, P. and Maslouhi, A. and Micheau, P.}, title = {Guided wave scattering by a geometrical or damage feature: Application to fatigue crack and machined notch}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2017}, volume = {10170}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020526300&doi=10.1117%2f12.2258646&partnerID=40&md5=9d4dd63a6dd0af7401a0c1ffbfaddda8}, doi = {https://doi.org/10.1117/12.2258646} } |
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Quaegebeur, N., Masson, P., Beaudet, N. and Sarret, P. | Touchscreen surface based on interaction of ultrasonic guided waves with a contact impedance | 2017 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 10166 |
conference | DOI URL |
Abstract: In the present paper, a touchscreen device is proposed, based on guided wave reflection and transmission induced by the presence of an object. The principle uses the advantages of other acoustic waves devices in terms of simplicity and applicability to any thin surface but is not subject to classical drawbacks (single-touch, sensitivity to scratches or contaminant, impossibility to follow motion of contact point). The theoretical interaction of guided waves with a contact impedance are first derived in order to define the requirements of the sensor in terms of frequency range, mode, sensor type and location, and embedded electronics. Design criteria and experimental validation on a small prototype (300 x 300 mm) are proposed to demonstrate the potential of the approach for simple, robust and reliable contact detection and contact pressure estimation of point-like or extended objects for consumer electronics or biomedical applications. © 2017 SPIE. | |||||
BibTeX:
@conference{Quaegebeur2017, author = {Quaegebeur, N. and Masson, P. and Beaudet, N. and Sarret, P.}, title = {Touchscreen surface based on interaction of ultrasonic guided waves with a contact impedance}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2017}, volume = {10166}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85026660962&doi=10.1117%2f12.2258622&partnerID=40&md5=9557cc918f1056a5ced2b7e88b86e35e}, doi = {https://doi.org/10.1117/12.2258622} } |
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Quaegebeur, N., Bouslama, N., Bilodeau, M., Guitel, R., Masson, P., Maslouhi, A. and Micheau, P. | Guided wave scattering by geometrical change or damage: Application to characterization of fatigue crack and machined notch | 2017 | Ultrasonics Vol. 73, pp. 187-195 |
article | DOI URL |
Abstract: Validation of guided-wave based systems for Non-Destructive Evaluation (NDE) and Structural Health Monitoring (SHM) under realistic conditions or environment requires complex setups. For this purpose, numerical or theoretical approaches are useful to save time and cost associated with experiential tests. However, the interaction with realistic geometrical (rivets, thickness changes, stiffeners, extrusions) or damage features (fatigue cracks, fillet cracks, delaminations, disbonds) must be accurately captured in order to be representative. In this paper, an experimental methodology is presented for estimating the far-field scattering of geometrical or damage features. The principle is based on the use of a Hankel transform of the measured 3D velocity field in order to evaluate with precision and repeatability the scattered pattern using a spatially averaged method. Application to scattering of a hole with simulated machined and real fatigue cracks is proposed. It is observed that the simulated machined crack generally used as a reference standard can only model accurately the transmission behaviour while the scattering patterns are only similar when the wavelength is about the size of the crack, limiting the practical use of machined cracks for experimental validation of SHM or NDE systems. © 2016 Elsevier B.V. | |||||
BibTeX:
@article{Quaegebeur2017187, author = {Quaegebeur, N. and Bouslama, N. and Bilodeau, M. and Guitel, R. and Masson, P. and Maslouhi, A. and Micheau, P.}, title = {Guided wave scattering by geometrical change or damage: Application to characterization of fatigue crack and machined notch}, journal = {Ultrasonics}, year = {2017}, volume = {73}, pages = {187-195}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84991489102&doi=10.1016%2fj.ultras.2016.09.014&partnerID=40&md5=e04225249412a8f0c9a50608458f0737}, doi = {https://doi.org/10.1016/j.ultras.2016.09.014} } |
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Robin, O., Atalla, N. and Berry, A. | Estimating transmission loss in coupled reverberant-anechoic rooms by measuring sound intensity with and without a test specimen (L) | 2017 | Journal of the Acoustical Society of America Vol. 141(3), pp. 1896-1899 |
article | DOI URL |
Abstract: A method for estimating the sound transmission loss of partitions in coupled reverberant-anechoic rooms is proposed, using two sound intensity measurements made before and after a test specimen is installed between the two rooms. Laboratory tests performed following a standard procedure and the suggested method with three different panels provide comparable transmission loss values. © 2017 Acoustical Society of America. | |||||
BibTeX:
@article{Robin20171896, author = {Robin, O. and Atalla, N. and Berry, A.}, title = {Estimating transmission loss in coupled reverberant-anechoic rooms by measuring sound intensity with and without a test specimen (L)}, journal = {Journal of the Acoustical Society of America}, year = {2017}, volume = {141}, number = {3}, pages = {1896-1899}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85016141107&doi=10.1121%2f1.4978039&partnerID=40&md5=6a41a6ce7ff1f11c0cfe8e745e42a9dc}, doi = {https://doi.org/10.1121/1.4978039} } |
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Serey, V., Renier, M., Castaings, M., Masson, P., Quaegebeur, N. and Micheau, P. | Selective guided waves generation in a bi-dimensional waveguide for damage detection | 2017 | Structural Health Monitoring 2017: Real-Time Material State Awareness and Data-Driven Safety Assurance - Proceedings of the 11th International Workshop on Structural Health Monitoring, IWSHM 2017 Vol. 1, pp. 1771-1778 |
conference | URL |
Abstract: SHM systems aim to detect defects in the structure they are attached to. Carefully selected pure guided waves are to be sent in the structure that acts as a waveguide in order to properly discriminate defects. For plates, this process has been developed in the past decades, e.g. using Lamb and SH waves. However, for a waveguide of finite crosssection, unconventional modes exist and particular attention must be paid to select the generated modes in the waveguide. For a same frequency-thickness product, the number of propagating modes in a bar is much larger than in an infinite plate and they may exhibit several displacement nodes over the bar width. In this paper, guided waves in a rectangular cross-section aluminum bar are studied, as representative of guided wave propagation along joint and extrusions. The two-dimensional Semi-Analytical Finite Element (SAFE 2D) method is used to obtain dispersion curves of all possible propagating modes, as well as mode shapes. Bar modes are generated experimentally in an aluminum bar using an ultrasonic multi-element probe, and detected with a Laser Doppler Vibrometer (LDV). Displacements and amplitudes obtained after processing of the measured data are in agreement with the predicted dispersion curves. Amplitude and phase measurements of modes generated by each excited element of the probe provide a transfer matrix, the inversion of which allows finding the excitation signals to simultaneously send to all elements in order to generate a desired pure mode. Finally, experiments are performed to confirm the selective generation, and to demonstrate a damage detection. | |||||
BibTeX:
@conference{Serey20171771, author = {Serey, V. and Renier, M. and Castaings, M. and Masson, P. and Quaegebeur, N. and Micheau, P.}, title = {Selective guided waves generation in a bi-dimensional waveguide for damage detection}, journal = {Structural Health Monitoring 2017: Real-Time Material State Awareness and Data-Driven Safety Assurance - Proceedings of the 11th International Workshop on Structural Health Monitoring, IWSHM 2017}, year = {2017}, volume = {1}, pages = {1771-1778}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85032433484&partnerID=40&md5=9754841803c783047e6dadaad7d3b8b6} } |
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Temporelli, R., Micheau, P. and Boisvert, M. | Agile and Low-Cost Experimental Evaluation of Fuel Consumption Reduction of a New Electrified Clutch Transmission Virtually Connected to a Vehicle | 2017 | SAE Technical Papers Vol. 2017-March(March) |
article | DOI URL |
Abstract: Automated Manual Transmission (AMT) based on classic electrohydraulic clutch actuation gives high performances and comfort to a recreational vehicle. However, overall power consumption remains high due to the pump efficiency. In addition, the pump is often driven by the vehicle's engine and thus is continuously working. To address this issue, a new electrified clutch based on electromechanical actuation has been designed and prototyped. In order to evaluate the effective fuel consumption reduction using this new clutch actuator, a low-cost and agile method is presented and used in this paper. Indeed, instead of integrating the clutch actuator in a real vehicle and performing expensive real emission test cycles on a road, this original method proposes to perform accurate semi-virtual emission test cycles. Moreover, the method allows to perform numerous test iterations in a short time. This consists in connecting the prototyped new electric clutch to a virtual vehicle in order to test it as it would be used in a real vehicle. A dedicated real-time rapid prototyping system (Opal-RT) runs the simplified vehicle dynamics and controls clutch algorithms to generate commands for the clutch actuator as a function of the measured clutch responses and as a function of the simulated vehicle dynamics. The method, entitled Actuator-In-The-Loop (AIL), is used to evaluate the fuel consumption of virtual vehicle connected to the prototyped new electric clutch, in compliance with the World-wide Motorcycle Emissions Test Cycle 3.2 (WMTC 3.2). On the same driving cycle, a fuel consumption comparison is achieved with an identical virtual vehicle equipped with a classic electrohydraulic clutch actuator. Finally, this experimental evaluation/comparison by the original AIL method leads to a mean vehicle fuel consumption reduction of 2.95% using the prototyped new electric. For a given vehicle and a given normalized driving cycle, the AIL method allows an accurate, low-cost and agile evaluation of any vehicle's actuator power consumption. © 2017 SAE International. | |||||
BibTeX:
@article{Temporelli2017, author = {Temporelli, R. and Micheau, P. and Boisvert, M.}, title = {Agile and Low-Cost Experimental Evaluation of Fuel Consumption Reduction of a New Electrified Clutch Transmission Virtually Connected to a Vehicle}, journal = {SAE Technical Papers}, year = {2017}, volume = {2017-March}, number = {March}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018394832&doi=10.4271%2f2017-01-1096&partnerID=40&md5=407734cdb7d5d884ac728a40c1f35903}, doi = {https://doi.org/10.4271/2017-01-1096} } |
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Temporelli, R. and Micheau, P. | Oscillations control of a transmission belt by Excitation Clipping using Clutch Clamping Control (E4C) | 2017 | Journal of Sound and Vibration Vol. 393, pp. 1-13 |
article | DOI URL |
Abstract: A transmission belt deals with non-linear phenomena such as parametric excitations that can bring the belt in an instability region resulting in large transverse oscillations. These oscillations can cause belt life deflection, noise and unexpected vibration on its environment. The present study proposes a new strategy to control oscillations of a transmission belt subject to periodic tension fluctuations. Indeed, for a transmission belt, periodic torque fluctuations cause periodic belt tension fluctuations which can be a source of excitation for the belt and resulting in belt oscillations under certain conditions. The presence of a clutch between the belt end-point and the source of torque fluctuations offers a means to clip torque fluctuations and thus to clip belt excitation. In keeping with this notion, belt oscillations can be controlled by an Excitation Clipping using Clutch Clamping Control (E4C) strategy. Through an example of a transmission belt subject to periodic tension fluctuations, the E4C strategy is presented and a new analytical model of belt behavior with its E4C strategy is constructed. Free belt oscillations (E4C is not activated) and controlled belt oscillations (E4C is activated) are observed through an experimental setup and predicted owing to the new analytical model. Finally, the E4C strategy leads to frequency unlocking that successfully removes belt oscillations. This new analytical model furthermore provides an accurate prediction of belt behavior with its E4C strategy. © 2017 Elsevier Ltd | |||||
BibTeX:
@article{Temporelli20171, author = {Temporelli, R. and Micheau, P.}, title = {Oscillations control of a transmission belt by Excitation Clipping using Clutch Clamping Control (E4C)}, journal = {Journal of Sound and Vibration}, year = {2017}, volume = {393}, pages = {1-13}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85009804064&doi=10.1016%2fj.jsv.2017.01.005&partnerID=40&md5=28f6183f7e78f5e2238f4c52ac3910d9}, doi = {https://doi.org/10.1016/j.jsv.2017.01.005} } |
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Temporelli, R., Micheau, P. and Boisvert, M. | Control of an electromechanical clutch actuator by a parallel Adaptive Feedforward and Bang-Bang controller: Simulation and Experimental results | 2017 | IFAC-PapersOnLine Vol. 50(1), pp. 4787-4793 |
article | DOI URL |
Abstract: Vehicle's powertrain performance and comfort are largely depending on the clutch control strategy for an Automated Manual Transmission (AMT). The aim of the clutch control strategy is to ensure the smooth running of clutch operational cases: a comfortable clutch launch (vehicle takes off smoothly without jerk), a fast upshift/downshift (gear ratio changes) and a fast clutch opening. In most industrial cases, regardless of clutch actuation technology, clutch control is managed by clutch pressure control. However, the clutch pressure control is a challenge regarding clutch non-linearities and time-varying parameters. In this paper, a parallel adaptive feedforward and bang-bang controller is proposed in order to control the clutch pressure with an electromechanical clutch actuator. In this system, a control issue comes from potential time-varying parameters but the main challenge comes from the hysteretic behavior of the system due to dry friction in the actuator assembly. An analytic model of the clutch and its electromechanical actuator including dry friction has been constructed and a prototype has been designed and integrated on a test bench. The parallel adaptive feedforward and bang-bang controller architecture and algorithms are developed. For three critical clutch operational cases, simulations and experiments have been run. Finally, in spite of time-varying parameters and a high hysteretic system behavior, simulation and experimental control results highlight that the controller allows a precise tracking of the pressure reference and a fast time response. © 2017 | |||||
BibTeX:
@article{Temporelli20174787, author = {Temporelli, R. and Micheau, P. and Boisvert, M.}, title = {Control of an electromechanical clutch actuator by a parallel Adaptive Feedforward and Bang-Bang controller: Simulation and Experimental results}, journal = {IFAC-PapersOnLine}, year = {2017}, volume = {50}, number = {1}, pages = {4787-4793}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85031802280&doi=10.1016%2fj.ifacol.2017.08.1368&partnerID=40&md5=3bce8c5265e00d14bd584d51ee135cd3}, doi = {https://doi.org/10.1016/j.ifacol.2017.08.1368} } |
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Todter, C., Robin, O., Bremner, P., Marchetto, C. and Berry, A. | Effect of Screens and Pinhole Size on Measured Fluctuating Surface Pressures Using a Micro-Electro-Mechanical Microphone Array | 2017 | SAE Technical Papers Vol. 2017-June(June) |
article | DOI URL |
Abstract: Surface pressure measurements using microphone arrays are still challenging, especially in an automotive context with cruising speeds around Mach 0.1. The separated turbulent boundary layer excitation and the side mirror wake flow generate both acoustic and aerodynamic components, which have wavenumbers that differ by a factor of approximately 10. This calls for high spatial resolution measurements to fully resolve the wavenumber-frequency spectrum. In a previous publication [1], the authors reported a micro-electro-mechanical (MEMS) surface microphone array that successfully used wavenumber analysis to quantify acoustic versus turbulence loading. It was shown that the measured surface pressure at each microphone could be strongly influenced by self-noise induced by the microphone "packaging", which can be attenuated with a suitable windscreen. This paper reports the results of wind tunnel tests to more accurately define the sensitivity of the MEMS microphone array with and without windscreens. The tests involved controlled attached boundary layer flow measurements in the anechoic wind tunnel at University of Sherbrooke. Different microphone sensing ports are evaluated as well as different microphone windscreens. Copyright © 2017 SAE International and Copyright © 2017 Institute of Noise Control Engineering. | |||||
BibTeX:
@article{Todter2017, author = {Todter, C. and Robin, O. and Bremner, P. and Marchetto, C. and Berry, A.}, title = {Effect of Screens and Pinhole Size on Measured Fluctuating Surface Pressures Using a Micro-Electro-Mechanical Microphone Array}, journal = {SAE Technical Papers}, year = {2017}, volume = {2017-June}, number = {June}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85024916315&doi=10.4271%2f2017-01-1783&partnerID=40&md5=0cbc70e681ecbc977ce0d9dbad2808ca}, doi = {https://doi.org/10.4271/2017-01-1783} } |
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Verdiere, K., Panneton, R., Atalla, N. and Elkoun, S. | Inverse Poroelastic Characterization of Open-Cell Porous Materials Using an Impedance Tube | 2017 | SAE Technical Papers Vol. 2017-June(June) |
article | DOI URL |
Abstract: A poroelastic characterization of open-cell porous materials using an impedance tube is proposed in this paper. Commonly, porous materials are modeled using Biot's theory. However, this theory requires several parameters which can be difficult to obtain by different methods (direct, indirect or inverse measurements). The proposed method retrieves all the Biot's parameters with one absorption measurement in an impedance tube for isotropic poroelastic materials following the Johnson-Champoux-Allard's model (for the fluid phase). The sample is a cylinder bonded to the rigid termination of the tube with a diameter smaller than the tube's one. In that case, a lateral air gap is voluntary induced to prevent lateral clamping. Using this setup, the absorption curve exhibits a characteristic elastic resonance (quarter wavelength resonance) and the repeatability is ensured by controlling boundary and mounting conditions. The inversion algorithm contains a global optimization process using an axisymmetric finite element code implemented in the Foam-X characterization software. To apply the inversion, the user must provide tube diameter, together with sample diameter, thickness, density, and absorption curve. Also, when available, some other parameters can be provided, such as open porosity, airflow resistivity, tortuosity, or Poisson's ratio. Providing these additional parameters improves the algorithm convergence. The algorithm is tested on different porous materials and compared to direct measurements. For some materials, the main experimental challenge is to make sure to excite the elastic resonance during impedance tube measurements. Once the resonance is excited, the proposed inversion algorithm finds Biot's parameters that are generally comparable with direct measurements. The validity and main limitations of the method are finally discussed. Copyright © 2017 SAE International. | |||||
BibTeX:
@article{Verdiere2017, author = {Verdiere, K. and Panneton, R. and Atalla, N. and Elkoun, S.}, title = {Inverse Poroelastic Characterization of Open-Cell Porous Materials Using an Impedance Tube}, journal = {SAE Technical Papers}, year = {2017}, volume = {2017-June}, number = {June}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85021452747&doi=10.4271%2f2017-01-1878&partnerID=40&md5=0d794ee5ae181fb8eab5fba14148e2f7}, doi = {https://doi.org/10.4271/2017-01-1878} } |
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Alimonti, L. and Atalla, N. | Efficient modeling of flat and homogeneous acoustic treatments for vibroacoustic finite element analysis. Direct field formulations | 2016 | Journal of Sound and Vibration Vol. 367, pp. 84-100 |
article | DOI URL |
Abstract: This paper is concerned with the development of a simplified model for noise control treatments to speed up finite element analysis in vibroacoustic applications. The methodology relies on the assumption that the acoustic treatment is flat and homogeneous. Moreover, its finite lateral extent is neglected. This hypothesis is justified by short wavelength and large dissipation, which suggest that the reflected field emanating from the acoustic treatment lateral boundaries does not substantially affect its dynamic response. Under these circumstances, the response of the noise control treatment can be formally obtained by means of convolution integrals involving simple analytical kernels (i.e. Green functions). Such fundamental solutions can be computed efficiently by the transfer matrix method. However, some arbitrariness arises in the formulation of the mathematical model, resulting in different baffling conditions at the two ends of the treatment to be considered. Thus, the paper investigates the possibility of different formulations (i.e. baffling conditions) within the same hybrid finite element-transfer matrix framework, seeking for the best strategy in terms of tradeoff between efficiency and accuracy. Numerical examples are provided to show strengths and limitations of the proposed methodology. © 2016 Elsevier Ltd. | |||||
BibTeX:
@article{Alimonti201684, author = {Alimonti, L. and Atalla, N.}, title = {Efficient modeling of flat and homogeneous acoustic treatments for vibroacoustic finite element analysis. Direct field formulations}, journal = {Journal of Sound and Vibration}, year = {2016}, volume = {367}, pages = {84-100}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957846646&doi=10.1016%2fj.jsv.2015.12.044&partnerID=40&md5=eec01fc9be251f6723fc9ca793888c09}, doi = {https://doi.org/10.1016/j.jsv.2015.12.044} } |
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Atalla, N., Sgard, F. and Hargreaves, J. | Finite element and boundary methods in structural acoustics and vibration [BibTeX] |
2016 | Acoustics Bulletin Vol. 41(1), pp. 58 |
article | URL |
BibTeX:
@article{Atalla201658, author = {Atalla, N. and Sgard, F. and Hargreaves, J.}, title = {Finite element and boundary methods in structural acoustics and vibration}, journal = {Acoustics Bulletin}, year = {2016}, volume = {41}, number = {1}, pages = {58}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014072058&partnerID=40&md5=1229fbdbe0bc16f2a632f08008aa651d} } |
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Benghanem, A., Gauthier, P.-A., Leblanc, L. and Berry, A. | The lasso and elastic-net algorithms for predictive sound quality models using large pool of predictive metrics and factors | 2016 | Canadian Acoustics - Acoustique Canadienne Vol. 44(3), pp. 174-175 |
article | URL |
Abstract: The lasso and elastic-net are tested for the prediction of listening tests results of consumer product. Listening tests were conducted with 40 participants according to a forced-choice pairwise comparison method. Tests were conducted using calibrated and equalized binaural reproduction over headphones. The test was based on a full-fractional design of experiments (DOE) with four factors. Once listening tests were completed, few post-processing steps were done. The lasso and elastic-net algorithms were compared for the prediction of listening tests results of consumer product for which 141 metrics and DOE factors were used as predictors. It was shown that the most promising algorithm is the lasso which is able to efficiently and strictly limit the number of metrics and provide a model that can be used in order to provide a set of understandable design guidelines. Typically, the elastic-net includes more predictors in the predictive SQ model. | |||||
BibTeX:
@article{Benghanem2016174, author = {Benghanem, A. and Gauthier, P.-A. and Leblanc, L. and Berry, A.}, title = {The lasso and elastic-net algorithms for predictive sound quality models using large pool of predictive metrics and factors}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2016}, volume = {44}, number = {3}, pages = {174-175}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85002772723&partnerID=40&md5=425bfd0ed76074cdfaaabf983983bc9f} } |
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Berry, A. and Gauthier, P.-A. | Spatial reproduction of aircraft cabin noise in a full-scale mock-up | 2016 | Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future, pp. 3425-3436 | conference | URL |
Abstract: Reproduction in a mock-up of aircraft cabin noise in various flight conditions is an interesting tool for the prediction, optimization, demonstration and jury testing of interior aircraft sound quality. To provide a faithfully reproduced sound environment, time, frequency and spatial characteristics of the actual sound field should be preserved. This communication presents a cabin sound reproduction system in a full-scale mock-up of a CRJ 1000 Bombardier aircraft cabin. The reference sound field is based on a spatial capture of the CRJ cabin sound in various flight conditions using a 80 microphone array. The reproduction approach presented here is based on multichannel equalization using regularized least-mean-square minimization. The system involves inertial actuators mounted on the mock-up trim panels as well as bass shakers and a sub-woofer. The communication will discuss the system design as well as objective and subjective evaluation. © 2016, German Acoustical Society (DEGA). All rights reserved. | |||||
BibTeX:
@conference{Berry20163425, author = {Berry, A. and Gauthier, P.-A.}, title = {Spatial reproduction of aircraft cabin noise in a full-scale mock-up}, journal = {Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future}, year = {2016}, pages = {3425-3436}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994642936&partnerID=40&md5=1e7266fa5d0f521199b64babc7b8950c} } |
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Berry, A. and Robin, O. | Identification of spatially correlated excitations on a bending plate using the Virtual Fields Method | 2016 | Journal of Sound and Vibration Vol. 375, pp. 76-91 |
article | DOI URL |
Abstract: This paper aims at identifying the autospectral density and spatial correlation functions of random excitations acting on the surface of a thin plate, from its measured vibration response. The general framework is the Virtual Fields Method (VFM), which was previously applied by the authors to the identification of deterministic excitations on plates. In the present paper, the VFM framework is extended to the case of spatially correlated excitations. It is shown that extraction of the loading power spectral density requires measuring power spectral density functions of transverse displacements and bending curvatures, which can be typically derived from contactless Laser Doppler Vibrometry measurements. The paper details the implementation of the VFM for random excitations, presents numerical simulations and experimental results for diffuse acoustic field excitation of a plate. © 2016 Elsevier Ltd. | |||||
BibTeX:
@article{Berry201676, author = {Berry, A. and Robin, O.}, title = {Identification of spatially correlated excitations on a bending plate using the Virtual Fields Method}, journal = {Journal of Sound and Vibration}, year = {2016}, volume = {375}, pages = {76-91}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84992295248&doi=10.1016%2fj.jsv.2016.03.042&partnerID=40&md5=1958a74eb4b6feafabdeb954a546b375}, doi = {https://doi.org/10.1016/j.jsv.2016.03.042} } |
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Beuvelet, S., Panneton, R., Desrochers, A. and Oddo, R. | Understanding sources and sound radiation of a snowmobile track | 2016 | Canadian Acoustics - Acoustique Canadienne Vol. 44(3), pp. 248-249 |
article | URL |
Abstract: The understanding of the noise generation by a snowmobile track and suspension has been improved. The most important excitation source was found to be the passage of the guiding wheels over the lugs. This excitation propagates in the suspension on which the tunnel of the snowmobile is attached. The sound radiation and the dynamics of the track have not been identified as important contributors in the system. Finally, depending on the track speed, the system has two preferred ways to generate noise, airborne noise from the suspension itself and structural sound radiation from the tunnel. | |||||
BibTeX:
@article{Beuvelet2016248, author = {Beuvelet, S. and Panneton, R. and Desrochers, A. and Oddo, R.}, title = {Understanding sources and sound radiation of a snowmobile track}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2016}, volume = {44}, number = {3}, pages = {248-249}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85002637273&partnerID=40&md5=1e3f902af5d2dac1822ede51ac7b6c79} } |
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Boisvert, M. and Micheau, P. | Estimators of wheel slip for electric vehicles using torque and encoder measurements | 2016 | Mechanical Systems and Signal Processing Vol. 76-77, pp. 665-676 |
article | DOI URL |
Abstract: For the purpose of regenerative braking control in hybrid and electrical vehicles, recent studies have suggested controlling the slip ratio of the electric-powered wheel. A slip tracking controller requires an accurate slip estimation in the overall range of the slip ratio (from 0 to 1), contrary to the conventional slip limiter (ABS) which calls for an accurate slip estimation in the critical slip area, estimated at around 0.15 in several applications. Considering that it is not possible to directly measure the slip ratio of a wheel, the problem is to estimate the latter from available online data. To estimate the slip of a wheel, both wheel speed and vehicle speed must be known. Several studies provide algorithms that allow obtaining a good estimation of vehicle speed. On the other hand, there is no proposed algorithm for the conditioning of the wheel speed measurement. Indeed, the noise included in the wheel speed measurement reduces the accuracy of the slip estimation, a disturbance increasingly significant at low speed and low torque. Herein, two different extended Kalman observers of slip ratio were developed. The first calculates the slip ratio with data provided by an observer of vehicle speed and of propeller wheel speed. The second observer uses an original nonlinear model of the slip ratio as a function of the electric motor. A sinus tracking algorithm is included in the two observers, in order to reject harmonic disturbances of wheel speed measurement. Moreover, mass and road uncertainties can be compensated with a coefficient adapted online by an RLS. The algorithms were implemented and tested with a three-wheel recreational hybrid vehicle. Experimental results show the efficiency of both methods. © 2016 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Boisvert2016665, author = {Boisvert, M. and Micheau, P.}, title = {Estimators of wheel slip for electric vehicles using torque and encoder measurements}, journal = {Mechanical Systems and Signal Processing}, year = {2016}, volume = {76-77}, pages = {665-676}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977950270&doi=10.1016%2fj.ymssp.2016.02.017&partnerID=40&md5=b4eff555bd22afc05f42021df1862d6d}, doi = {https://doi.org/10.1016/j.ymssp.2016.02.017} } |
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Boulandet, R., Michau, M., Herzog, P., Micheau, P. and Berry, A. | A sensorless method for measuring the point mobility of mechanical structures | 2016 | Journal of Sound and Vibration Vol. 378, pp. 14-27 |
article | DOI URL |
Abstract: This paper presents a convenient and cost-effective experimental tool for measuring the mobility characteristics of a mechanical structure. The objective is to demonstrate that the point mobility measurement can be performed using only an electrodynamic inertial exciter. Unlike previous work based on voice coil actuators, no load cell or accelerometer is needed. Instead, it is theoretically shown that the mobility characteristics of the structure can be estimated from variations in the electrical input impedance of the actuator fixed onto it, provided that the electromechanical parameters of the actuator are known. The proof of concept is made experimentally using a cheap commercially available actuator on a simply supported plate, leading to a good dynamic range from 100 Hz to 1 kHz. The methodology to assess the basic parameters of the actuator is also given. Measured data are compared to a standard shaker testing and the strengths and weaknesses of the sensorless mobility measuring device are discussed. It is believed that this sensorless mobility measuring device can be a convenient experimental tool to determine the dynamic characteristics of a wide range of mechanical structures. © 2016 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Boulandet201614, author = {Boulandet, R. and Michau, M. and Herzog, P. and Micheau, P. and Berry, A.}, title = {A sensorless method for measuring the point mobility of mechanical structures}, journal = {Journal of Sound and Vibration}, year = {2016}, volume = {378}, pages = {14-27}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84973891568&doi=10.1016%2fj.jsv.2016.05.034&partnerID=40&md5=1790072eb558205a4cf27abb79b54970}, doi = {https://doi.org/10.1016/j.jsv.2016.05.034} } |
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Boulandet, R., Michau, M., Micheau, P. and Berry, A. | Aircraft panel with sensorless active sound power reduction capabilities through virtual mechanical impedances | 2016 | Journal of Sound and Vibration Vol. 361, pp. 2-19 |
article | DOI URL |
Abstract: This paper deals with an active structural acoustic control approach to reduce the transmission of tonal noise in aircraft cabins. The focus is on the practical implementation of the virtual mechanical impedances method by using sensoriactuators instead of conventional control units composed of separate sensors and actuators. The experimental setup includes two sensoriactuators developed from the electrodynamic inertial exciter and distributed over an aircraft trim panel which is subject to a time-harmonic diffuse sound field. The target mechanical impedances are first defined by solving a linear optimization problem from sound power measurements before being applied to the test panel using a complex envelope controller. Measured data are compared to results obtained with sensor-actuator pairs consisting of an accelerometer and an inertial exciter, particularly as regards sound power reduction. It is shown that the two types of control unit provide similar performance, and that here virtual impedance control stands apart from conventional active damping. In particular, it is clear from this study that extra vibrational energy must be provided by the actuators for optimal sound power reduction, mainly due to the high structural damping in the aircraft trim panel. Concluding remarks on the benefits of using these electrodynamic sensoriactuators to control tonal disturbances are also provided. © 2015 Elsevier Ltd. | |||||
BibTeX:
@article{Boulandet20162, author = {Boulandet, R. and Michau, M. and Micheau, P. and Berry, A.}, title = {Aircraft panel with sensorless active sound power reduction capabilities through virtual mechanical impedances}, journal = {Journal of Sound and Vibration}, year = {2016}, volume = {361}, pages = {2-19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84952628993&doi=10.1016%2fj.jsv.2015.09.042&partnerID=40&md5=2b3f9fdc948dcfb73fe68bc57f69f8d7}, doi = {https://doi.org/10.1016/j.jsv.2015.09.042} } |
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Carpentier, J., Thomas, J.-H., Pézerat, C., Bailly, C. and Berry, A. | Comprehension of phenomena generating acoustic noise inside the passenger compartment of cars. Sources identification and simulation | 2016 | ICSV 2016 - 23rd International Congress on Sound and Vibration: From Ancient to Modern Acoustics | conference | URL |
Abstract: This study explains how to develop and to adapt the Force Analysis Techniques (FAT) used to identify the parietal excitations on a car window glass. The goal is to measure the aeroacoustic load liable to the annoying noises inside the passenger compartment of cars. The main idea of FAT is to use the plate vibrations in order to find the pressure field. The displacement fields are measured and injected into the motion equation of the plate in order to calculate the force distribution exciting the structure. In order to do so, spatial derivatives are calculated by approximation by a judiciously selected finite difference model. This model introduces a wavenumber filtering of the excitation. Only the low wavenumber components are reconstructed. This study proves the potentiality of the different Force Analysis Techniques, FAT and CFAT (Corrected Force Analysis Technique) and explains how the filtering can be modified and controlled by finding new finite difference models. | |||||
BibTeX:
@conference{Carpentier2016, author = {Carpentier, J. and Thomas, J.-H. and Pézerat, C. and Bailly, C. and Berry, A.}, title = {Comprehension of phenomena generating acoustic noise inside the passenger compartment of cars. Sources identification and simulation}, journal = {ICSV 2016 - 23rd International Congress on Sound and Vibration: From Ancient to Modern Acoustics}, year = {2016}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84987916923&partnerID=40&md5=68f04653c5452e4844c1ab2ce7f0536f} } |
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Chazot, J.-D., Robin, O., Guyader, J.-L. and Atalla, N. | Diffuse acoustic field produced in reverberant rooms: A boundary diffuse field index | 2016 | Acta Acustica united with Acustica Vol. 102(3), pp. 503-516 |
article | DOI URL |
Abstract: An as diffuse as possible acoustic field is pursued when performing measurements that make use of a reverberant room. The diffusivity descriptors that are commonly used to qualify the actual sound field in such a room are calculated in the room volume, away from boundaries. This is somewhat contradictory with the fact that for sound insulation and sound absorption measurements as examples, specimens are placed at room boundaries either a wall or the floor. This work presents a characterization of the sound pressure field at the boundaries of a reverberant room in order to evaluate the diffusivity of the excitation at these specific locations. A boundary diffuse field index is proposed, numerically evaluated and then tested in two reverberant chambers in steady state conditions. It is shown that this index allows evaluating the boundary diffusivity in a given reverberant room according to its geometry and other relevant parameters, such as the sound source location or the presence of sound diffusers. © S. Hirzel Verlag · EAA. | |||||
BibTeX:
@article{Chazot2016503, author = {Chazot, J.-D. and Robin, O. and Guyader, J.-L. and Atalla, N.}, title = {Diffuse acoustic field produced in reverberant rooms: A boundary diffuse field index}, journal = {Acta Acustica united with Acustica}, year = {2016}, volume = {102}, number = {3}, pages = {503-516}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84968832520&doi=10.3813%2fAAA.918968&partnerID=40&md5=477c1008023055695f96a00b978968ff}, doi = {https://doi.org/10.3813/AAA.918968} } |
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Coulon, J.-M., Atalla, N. and Desrochers, A. | Optimization of concentric array resonators for wide band noise reduction | 2016 | Applied Acoustics Vol. 113, pp. 109-115 |
article | DOI URL |
Abstract: In air duct noise control, Helmholtz resonators (HR) are considered as narrow band attenuators. For some applications they can be combined in line to form a wide band silencer. This study investigates the role of distance between HR side branch openings on the whole array attenuation. In the case of two resonators with same performance, the optimal distance can be calculated and corresponds to the quarter wave of HR mean frequency. On three or more HR arrays, relationships between resonators parameters and optimal lengths are much more complex. Tuning of such a device requires taking many geometrically coupled parameters into account; hence, design has to be automated. To operate this process, a 2D FEM COMSOL model has been coupled to a global MATLAB optimization solver. Among different types of constructions, arrays made of concentric resonators with transversal openings offers the most efficient and flexible design to optimize distance between openings. This methodology was applied to an existing turbo compressor silencer. Modifying openings and chambers arrangement, using the proposed approach increased the attenuation band by 10%. Another application concerning an air box for a two stroke engine was also investigated. This resulted in a 16L two chambers concept, being replaced by a more compact and more efficient, 8.3L wide band silencer, made of 8 resonators. With this approach it therefore becomes possible to handle available space and required noise attenuation on a required frequency band, all in one process. © 2016 Elsevier Ltd | |||||
BibTeX:
@article{Coulon2016109, author = {Coulon, J.-M. and Atalla, N. and Desrochers, A.}, title = {Optimization of concentric array resonators for wide band noise reduction}, journal = {Applied Acoustics}, year = {2016}, volume = {113}, pages = {109-115}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84976576255&doi=10.1016%2fj.apacoust.2016.06.015&partnerID=40&md5=18b233e5f1afdce16c9da8f3ea0009d9}, doi = {https://doi.org/10.1016/j.apacoust.2016.06.015} } |
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Gauthier, P.-A., Pasco, Y. and Berry, A. | Generalized singular value decomposition for personalized audio using loudspeaker array | 2016 | Proceedings of the AES International Conference Vol. 2016-July |
conference | URL |
Abstract: Personalized audio is the creation of independent sound zones. The zones are distinguished as the bright zone and the dark zone. The desired audio signal should be audible in the bright zone and reduced in the dark zone. Known methods are the pressure matching method, acoustic contrast maximization, beamforming, and high-pass filtering of cylindrical harmonic expansions. Several challenges are related to personalized audio, including the sound pressure level difference between bright and dark zones. This paper presents a theoretical investigation of a new potential method to achieve personalized audio: Generalized singular value decomposition of multichannel transfer matrices for the automatic creation of source distributions that independently operate on each zone. Results of simulations provide convincing results. | |||||
BibTeX:
@conference{Gauthier2016, author = {Gauthier, P.-A. and Pasco, Y. and Berry, A.}, title = {Generalized singular value decomposition for personalized audio using loudspeaker array}, journal = {Proceedings of the AES International Conference}, year = {2016}, volume = {2016-July}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85009989268&partnerID=40&md5=4d3efeca090ca8cce0162028791921ff} } |
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Gauthier, P.-A., Camier, C., Lebel, F.-A., Pasco, Y., Berry, A., Langlois, J., Verron, C. and Guastavino, C. | Experiments of multichannel least-square methods for sound field reproduction inside aircraft mock-up: Objective evaluations | 2016 | Journal of Sound and Vibration Vol. 376, pp. 194-216 |
article | DOI URL |
Abstract: Sound environment reproduction of various flight conditions in aircraft mock-ups is a valuable tool for the study, prediction, demonstration and jury testing of interior aircraft sound quality and annoyance. To provide a faithful reproduced sound environment, time, frequency and spatial characteristics should be preserved. Physical sound field reproduction methods for spatial sound reproduction are mandatory to immerse the listener?s body in the proper sound fields so that localization cues are recreated at the listener?s ears. Vehicle mock-ups pose specific problems for sound field reproduction. Confined spaces, needs for invisible sound sources and very specific acoustical environment make the use of open-loop sound field reproduction technologies such as wave field synthesis (based on free-field models of monopole sources) not ideal. In this paper, experiments in an aircraft mock-up with multichannel least-square methods and equalization are reported. The novelty is the actual implementation of sound field reproduction with 3180 transfer paths and trim panel reproduction sources in laboratory conditions with a synthetic target sound field. The paper presents objective evaluations of reproduced sound fields using various metrics as well as sound field extrapolation and sound field characterization. © 2016 Elsevier Ltd | |||||
BibTeX:
@article{Gauthier2016194, author = {Gauthier, P.-A. and Camier, C. and Lebel, F.-A. and Pasco, Y. and Berry, A. and Langlois, J. and Verron, C. and Guastavino, C.}, title = {Experiments of multichannel least-square methods for sound field reproduction inside aircraft mock-up: Objective evaluations}, journal = {Journal of Sound and Vibration}, year = {2016}, volume = {376}, pages = {194-216}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84966708453&doi=10.1016%2fj.jsv.2016.04.027&partnerID=40&md5=90e2c2f7e158a5723aba7d45b6094afb}, doi = {https://doi.org/10.1016/j.jsv.2016.04.027} } |
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Gholami, M., Doutres, O. and Atalla, N. | Effect of variability in micro-geometry of polyurethane foams on the double wall transmission loss | 2016 | Canadian Acoustics - Acoustique Canadienne Vol. 44(3), pp. 178-179 |
article | URL |
Abstract: The impacts of PU foam microstructure variability and macroscopic properties on the transmission loss (TL) of a laterally infinite double wall system are studied. The contribution of input parameters on the output, in variance based techniques, is investigated by quantifying the impact of input variation on the output variance. A global sensitivity analysis method is used to determine the output sensitivity when the inputs vary over wide ranges. 15mm PU foam is bonded to the excited, 1mm steel plate. The foam is relaxed from a 2mm heavy layer (septum) by adding a 5mm air space. Decoupling the heavy mass from PU foam by air-gap allows us to account, at the same time, for absorption and isolation problem. Laterally infinite considered system is excited acoustically by an oblique plane wave. The transmission loss is calculated using transfer matrix method. It is shown that the impact of strut length is dominant where foam is highly reticulated. While, the reticulation rate takes the lead when close pore content is high. | |||||
BibTeX:
@article{Gholami2016178, author = {Gholami, M.S. and Doutres, O. and Atalla, N.}, title = {Effect of variability in micro-geometry of polyurethane foams on the double wall transmission loss}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2016}, volume = {44}, number = {3}, pages = {178-179}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85002591640&partnerID=40&md5=182359ffeb69eb51e80acc175a8e94e4} } |
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Guenfoud, N., Robin, O., Panneton, R., Desrochers, A. and Belgacem, W. | Comparison of two methods of transfer path analysis applied to snowmobile for noise source identification | 2016 | Canadian Acoustics - Acoustique Canadienne Vol. 44(3), pp. 252-253 |
article | URL |
Abstract: The methodology of TPA (Transfer Path Analysis) and OTPA (Operational Transfer Path Analysis) were compared for an industrial case in terms of reconstruction of radiated pressure and transfer path identification. This study was focused on the noise linked to the excitation corresponding to the engagement of the drive shaft on the track by the sprocket teeth (composed of eight teeth). Twelve 3D accelerometers (named A1-A12) were placed on the suspension, and three target microphones were positioned in the room in front of the suspension. The methodologies of TPA and OTPA were applied to the rear suspension of the snowmobile. The OTPA is quicker to implement since measurements of H2 are no longer needed, and it avoids limitations linked to bandwidth-limited transfer functions. The TPA generally provides more precise predictions; however both methods provided a satisfactory identification of transfer paths. This was confirmed by noise reduction results obtained with additional tests on a snowmobile including modifications of the identified main paths and noise contributors. | |||||
BibTeX:
@article{Guenfoud2016252, author = {Guenfoud, N. and Robin, O. and Panneton, R. and Desrochers, A. and Belgacem, W.}, title = {Comparison of two methods of transfer path analysis applied to snowmobile for noise source identification}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2016}, volume = {44}, number = {3}, pages = {252-253}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85002522465&partnerID=40&md5=f00205a1d00a3b8c6c16c6e3056a340b} } |
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Halkyard, C. and Masson, P. | Time-domain flexural wave intensity estimation in orthotropic Kirchhoff plates | 2016 | Journal of Sound and Vibration Vol. 368, pp. 55-70 |
article | DOI URL |
Abstract: In this paper, a method for estimating the vibrational energy flow associated with the flexural vibration of an orthotropic Kirchhoff plate, in the time-domain, is presented. The approach is based on the plane propagating wave solution to the equation of motion, and uses a Fourier series approximation of the wave field. The various linear and angular velocities, shear forces and moments that are needed to calculate the energy flow are estimated by digitally filtering and combining the outputs of an array of sensors. A similar approach is used to reconstruct the local wave field to provide an estimate of the wave propagation direction. The theoretical basis of the approach is described, and design considerations for the sensor array and for the filters used for parameter estimation are discussed. Simulations are presented for plane flexural waves and for transient transverse point force excitation of a range of orthotropic plates having different material properties, using a simulated array of velocity sensors. These simulations show that the method can provide accurate estimates of the magnitude and direction of the vibrational energy flow, as well as of the propagation direction of a single wave train or 'burst', provided that the sensor array is sufficiently distant from the excitation point. This is consistent with preliminary experimental measurements, also presented in this paper, performed on a composite orthotropic plate. © 2015 Elsevier Ltd. | |||||
BibTeX:
@article{Halkyard201655, author = {Halkyard, C.R. and Masson, P.}, title = {Time-domain flexural wave intensity estimation in orthotropic Kirchhoff plates}, journal = {Journal of Sound and Vibration}, year = {2016}, volume = {368}, pages = {55-70}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957824182&doi=10.1016%2fj.jsv.2015.12.024&partnerID=40&md5=a3531d3894d874e4305a3a4585d9da14}, doi = {https://doi.org/10.1016/j.jsv.2015.12.024} } |
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Kohlhauer, M., Berdeaux, A., Kerber, R., Micheau, P., Ghaleh, B. and Tissier, R. | Liquid Ventilation for the Induction of Ultrafast Hypothermia in Resuscitation Sciences: A Review | 2016 | Therapeutic Hypothermia and Temperature Management Vol. 6(2), pp. 63-70 |
article | DOI URL |
Abstract: Liquid ventilation was initially proposed for lung lavage and respiratory support. More recently, it was also investigated as an experimental strategy for ultrafast cooling or organ preservation during ischemic disorders. The goal of this article is to identify and review the studies that investigated liquid ventilation in the field of resuscitation sciences. An exhaustive analysis of the literature was performed using the Medline database up to 15th September 2015. Articles were selected according to their relevance. All articles focusing on respiratory support were excluded. On the basis of 76 retrieved studies from the Medline database, 29 were included in this review. All studies were experimental reports and most of them investigated the cooling properties of liquid ventilation in animal models of experimental cardiac arrest or coronary artery occlusion in rabbits or pigs. Animal studies demonstrated a wide range of potential applications of total liquid ventilation in resuscitation sciences. This strategy is able to provide ultrafast cooling, independent of the body weight. In animal models of cardiopulmonary resuscitation, it was shown to provide potent benefits widely linked to cooling rapidity. © Copyright 2016, Mary Ann Liebert, Inc. 2016. | |||||
BibTeX:
@article{Kohlhauer201663, author = {Kohlhauer, M. and Berdeaux, A. and Kerber, R.E. and Micheau, P. and Ghaleh, B. and Tissier, R.}, title = {Liquid Ventilation for the Induction of Ultrafast Hypothermia in Resuscitation Sciences: A Review}, journal = {Therapeutic Hypothermia and Temperature Management}, year = {2016}, volume = {6}, number = {2}, pages = {63-70}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85006192434&doi=10.1089%2fther.2015.0024&partnerID=40&md5=d7b9ef1b22b0fec265f16fa363ca0c02}, doi = {https://doi.org/10.1089/ther.2015.0024} } |
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Lacerte, M.-O., Pouliot, G., Plante, J.-S. and Micheau, P. | Design and Experimental Demonstration of a Seamless Automated Manual Transmission using an Eddy Current Torque Bypass Clutch for Electric and Hybrid Vehicles | 2016 | SAE International Journal of Alternative Powertrains Vol. 5(1), pp. 13-22 |
article | DOI URL |
Abstract: Electric Vehicles (EVs) with single-ratio gearbox provide high levels of smoothness, but using multi-speed gearbox can provide significant benefits in terms of vehicle acceleration, top speed, powertrain cost, mass, and energy consumption. In particular, Automated Manual Transmissions (AMTs) have characteristics of smooth shifts without torque interruption when coupled to a torque bypass clutch. However, conventional friction clutches are not best suited as torque bypass clutches because of their limited controllability and because large amount of heat must be dissipated to slow down the motor during gearshifts. This paper studies the feasibility of a seamless AMT architecture for EVs and Hybrid Electric Vehicles (HEVs) using an eddy current torque bypass clutch that is highly controllable, robust, low cost, and has no wearable parts. A system-level study using a backward-facing model is used to assess the advantages of multi-speed gearboxes for EVs in terms of energy consumption, powertrain cost, and mass. A full-scale clutch prototype is designed for a custom two-speed AMT of an 80 kW EV. Numerical simulations show that a two-speed gearbox can improve energy consumption by 7.2 % for a compact class EV such as the Nissan Leaf. Moreover, using two gear ratios allows a downsizing of the electric motor, which could reduce powertrain cost and mass by 23.1 % and 15.6 %, respectively. The clutch is characterized experimentally and its maximum torque agrees well with analytical results (within 6 %). The prototype performed a seamless shift on a test bench demonstrating the viability of using an eddy current clutch for torque bypass clutches in AMTs. © Copyright 2016 SAE International. | |||||
BibTeX:
@article{Lacerte201613, author = {Lacerte, M.-O. and Pouliot, G. and Plante, J.-S. and Micheau, P.}, title = {Design and Experimental Demonstration of a Seamless Automated Manual Transmission using an Eddy Current Torque Bypass Clutch for Electric and Hybrid Vehicles}, journal = {SAE International Journal of Alternative Powertrains}, year = {2016}, volume = {5}, number = {1}, pages = {13-22}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975736370&doi=10.4271%2f2015-01-9144&partnerID=40&md5=e0ac000377d7221a62562fca7009a579}, doi = {https://doi.org/10.4271/2015-01-9144} } |
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Lecomte, P., Gauthier, P.-A., Langrenne, C., Berry, A. and Garcia, A. | A fifty-node lebedev grid and its applications to ambisonics | 2016 | AES: Journal of the Audio Engineering Society Vol. 64(11), pp. 868-881 |
article | DOI URL |
Abstract: This paper investigates the use of 50-node Lebedev grid for sound field capture and reproduction using Ambisonic approach. This grid is derived from rotationally-invariant quadrature rules, for which the underlying theory is recalled. Special attention is paid to spatial aliasing artifacts at capture and reproduction steps. While comparing a 50-node Lebedev grid with a Fliege and a t-design grid that both use almost the same number of nodes, it is shown that the Lebedev grid provides the best performance in terms of sound field capture and reproduction. Finally, a multi-band multi-order decoder is presented. These decoders take advantages of the inherent nested sub-grids when following the rotationally-invariant quadrature approach. | |||||
BibTeX:
@article{Lecomte2016868, author = {Lecomte, P. and Gauthier, P.-A. and Langrenne, C. and Berry, A. and Garcia, A.}, title = {A fifty-node lebedev grid and its applications to ambisonics}, journal = {AES: Journal of the Audio Engineering Society}, year = {2016}, volume = {64}, number = {11}, pages = {868-881}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85011661235&doi=10.17743%2fjaes.2016.0036&partnerID=40&md5=4c0bcb7e34339021f6ce2ca2fb5a2bb3}, doi = {https://doi.org/10.17743/jaes.2016.0036} } |
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Lépine, J., Champoux, Y. and Drouet, J.-M. | A Laboratory Excitation Technique to Test Road Bike Vibration Transmission | 2016 | Experimental Techniques Vol. 40(1), pp. 227-234 |
article | DOI URL |
Abstract: This paper describes a technique designed to measure the in-situ acceleration signals that will be used to drive a road simulator in the study of road bike vibration transmission in a laboratory setting. To measure the signals, a bike mounted by a cyclist and towed by a motor vehicle is used. A road simulator using actuators driven by a digital signal is described. The impulse response of the bike used to measure road data is convoluted with the road acceleration in order to obtain the required actuator signal. The reproduction capacity of the simulator is evaluated by comparing the frequency content as well as the time statistical parameters of the acceleration signal measurement with road to the acceleration obtained on the simulator. On a granular road with a broadband excitation spectrum, the vertical excitation obtained with the simulator adequately mimics the measured road acceleration. This technique can be used to compare vibration transmission characteristics among different road bikes. © 2016, The Society for Experimental Mechanics, Inc. | |||||
BibTeX:
@article{Lépine2016227, author = {Lépine, J. and Champoux, Y. and Drouet, J.-M.}, title = {A Laboratory Excitation Technique to Test Road Bike Vibration Transmission}, journal = {Experimental Techniques}, year = {2016}, volume = {40}, number = {1}, pages = {227-234}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84965166766&doi=10.1007%2fs40799-016-0026-8&partnerID=40&md5=c0482c5514cd01fa37743791d726a235}, doi = {https://doi.org/10.1007/s40799-016-0026-8} } |
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Lépine, J., Champoux, Y. and Drouet, J.-M. | Test Protocol for In-situ Bicycle Wheel Dynamic Comfort Comparison | 2016 | Procedia Engineering Vol. 147, pp. 568-572 |
conference | DOI URL |
Abstract: Bicycle comfort is very important especially for enthusiastic road cyclists who can spend several hours astride their bicycle in a single ride. Being an abstract concept, several researchers proposed to assess bicycle comfort by measuring the level of vibration transmitted to the cyclist. This can be measured in a controlled laboratory environment but it requires cumbersome and expensive road excitation simulation setup. In-situ measurements are an alternative solution but the experiment repeatability is not as good as in the laboratory because many experimental factors are difficult to control while riding a bicycle on the road (e.g. cyclist's posture on the bicycle). This paper presents a test protocol to evaluate bicycle comfort with minimal uncertainty inherent of the in-situ experiment. Three main elements are used to enhance measurement repeatability and therefore increase the differentiating capability of the protocol: the measurand selection, the bicycle propulsion and the design of experiments. The power absorbed by the cyclist is used to quantify the level of vibration transmitted to the cyclist because it is far less sensitive to variation of cyclists' posture than to the other measurands used to assess comfort such as acceleration. The bicycle is propelled from an external source which increases precision of the bicycle speed control during the experiment and eliminates measurement noise coming from the bicycle drivetrain. The experiment is specifically designed in term of test runs' duration and replication to improve its repeatability. The protocol is presented in this paper as a case study of bicycle wheel comfort comparison and can be extended to any components or a complete bicycle comfort comparison. The same case study has been performed with different test methods in the laboratory which are used to assess and validate the accuracy of the presented in-situ protocol. © 2016 The Authors. Published by Elsevier Ltd. | |||||
BibTeX:
@conference{Lépine2016568, author = {Lépine, J. and Champoux, Y. and Drouet, J.-M.}, title = {Test Protocol for In-situ Bicycle Wheel Dynamic Comfort Comparison}, journal = {Procedia Engineering}, year = {2016}, volume = {147}, pages = {568-572}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84983003917&doi=10.1016%2fj.proeng.2016.06.241&partnerID=40&md5=85fe3c6d9c50918b6a23494dbb331800}, doi = {https://doi.org/10.1016/j.proeng.2016.06.241} } |
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Luu, H., Perrot, C., Monchiet, V. and Panneton, R. | Sound waves and angular orientation in fibrous materials | 2016 | Proceedings of ISMA 2016 - International Conference on Noise and Vibration Engineering and USD2016 - International Conference on Uncertainty in Structural Dynamics, pp. 501-512 | conference | URL |
Abstract: Angular orientation is a state of fibers which can be intentionally changed to modify the properties of the corresponding material. Here, the angular orientation tensor of a fibrous material is identified from scanning electron microscope images, in order to construct a model of the microgeometry, in which the partial differential equations governing the physics at the upper scale can be solved. Permeability and impedance tube measurements show that the corresponding model is a good candidate to simulate the transport properties of fibrous materials. It is also shown that the transport properties of the samples are highly affected and tunable through the angular orientation of the fibers. The proposed numerical approach can be applied to evaluate the effective transport and sound absorbing properties of general fibrous materials just from the geometrical information embodied in the microstructural parameters of single fibers, the fibers orientation distribution and the bulk porosity. | |||||
BibTeX:
@conference{Luu2016501, author = {Luu, H.T. and Perrot, C. and Monchiet, V. and Panneton, R.}, title = {Sound waves and angular orientation in fibrous materials}, journal = {Proceedings of ISMA 2016 - International Conference on Noise and Vibration Engineering and USD2016 - International Conference on Uncertainty in Structural Dynamics}, year = {2016}, pages = {501-512}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018160600&partnerID=40&md5=adf69cfd80a67b70930a32c1e08fb1af} } |
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Marchetto, C., Maxit, L., Robin, O. and Berry, A. | Vibro-acoustic response of panels excited by a diffuse acoustic field: Experimental estimation of sensitivity functions using a reciprocity principle | 2016 | Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future, pp. 7675-7682 | conference | URL |
Abstract: The experimental characterization of the vibroacoustic response of panels excited by a Diffuse Acoustic Field (DAF) is of great interest, especially for building acoustics and industrial applications. Theoretically, a DAF is usually defined as an infinite number of uncorrelated plane waves with uniformly distributed incidence angles. However, completely diffuse conditions can hardly be reached in practice, and important variabilities are also seen between sound insulation tests performed in different laboratories. To circumvent these issues, a methodology is developed for experimentally characterizing a panel response to a DAF excitation, defined by its theoretical model. Indeed, the formulation of the problem in the wavenumber domain allows estimating the system response at a given M point from the DAF cross-spectral density function and so-called "sensitivity functions". These functions characterize the panel vibroacoustic response to parietal plane waves and can be experimentally determined using a reciprocity principle, which states that they are equal to the panel velocity field expressed in the wavenumber domain when the system is excited by a point source at a point M. For validation purposes, the proposed technique is applied numerically and experimentally on a simply supported rectangular plate. The interests and possible applications of this approach are finally discussed. © 2016, German Acoustical Society (DEGA). All rights reserved. | |||||
BibTeX:
@conference{Marchetto20167675, author = {Marchetto, C. and Maxit, L. and Robin, O. and Berry, A.}, title = {Vibro-acoustic response of panels excited by a diffuse acoustic field: Experimental estimation of sensitivity functions using a reciprocity principle}, journal = {Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future}, year = {2016}, pages = {7675-7682}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994593471&partnerID=40&md5=a8d308f48f9bf25272a6acb782ecbb09} } |
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Méjane, J., Panneton, R., Desrochers, A. and Oddo, R. | A data processing method for noise measurements of snowmobiles and their sub-systems on test bench | 2016 | Canadian Acoustics - Acoustique Canadienne Vol. 44(3), pp. 254-255 |
article | URL |
Abstract: A data processing method based on bench tests measurement, allowing reliable noise comparison between two different models of a snowmobile CVT, and predictions on Pass-by noise reduction. An antenna of four microphones faces the CVT within 2.2 meters. To take noise level dependency to engine speed into account, data will be processed and ranked in relation to the engine speed. Included statistical indicators make easier comparison and prediction, as long as test conditions on the bench are well controlled (reproduce real use conditions), and number of measures is large enough. Test bench measurement saves time and does not depend on environmental conditions compared with Pass-by measurement. The comparison fairly matches with Pass-by results and predictions seem to be made with reliability. | |||||
BibTeX:
@article{Méjane2016254, author = {Méjane, J. and Panneton, R. and Desrochers, A. and Oddo, R.}, title = {A data processing method for noise measurements of snowmobiles and their sub-systems on test bench}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2016}, volume = {44}, number = {3}, pages = {254-255}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85002902605&partnerID=40&md5=70da91ec0ae79239f63285493f78d2c9} } |
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Moghadam, P., Quaegebeur, N. and Masson, P. | Design and optimization of a multi-element piezoelectric transducer for mode-selective generation of guided waves | 2016 | Smart Materials and Structures Vol. 25(7) |
article | DOI URL |
Abstract: A novel multi-element piezoelectric transducers (MEPT) is designed, optimized, machined and experimentally tested to improve structural health monitoring systems for mode-selective generation of guided waves (GW) in an isotropic structure. GW generation using typical piezoceramics makes the signal processing and consequently damage detection very complicated because at any driving frequency at least two fundamental symmetric (S 0) and antisymmetric (A 0) modes are generated. To prevent this, mode selective transducer design is proposed based on MEPT. A numerical method is first developed to extract the interfacial stress between a single piezoceramic element and a host structure and then used as the input of an analytical model to predict the GW propagation through the thickness of an isotropic plate. Two novel objective functions are proposed to optimize the interfacial shear stress for both suppressing unwanted mode(s) and maximizing the desired mode. Simplicity and low manufacturing cost are two main targets driving the design of the MEPT. A prototype MEPT is then manufactured using laser micro-machining. An experimental procedure is presented to validate the performances of the MEPT as a new solution for mode-selective GW generation. Experimental tests illustrate the high capability of the MEPT for mode-selective GW generation, as unwanted mode is suppressed by a factor up to 170 times compared with the results obtained with a single piezoceramic. © 2016 IOP Publishing Ltd. | |||||
BibTeX:
@article{Moghadam2016, author = {Moghadam, P.Y. and Quaegebeur, N. and Masson, P.}, title = {Design and optimization of a multi-element piezoelectric transducer for mode-selective generation of guided waves}, journal = {Smart Materials and Structures}, year = {2016}, volume = {25}, number = {7}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975259987&doi=10.1088%2f0964-1726%2f25%2f7%2f075037&partnerID=40&md5=f461450379dd8c08aad34ad1b8e122fc}, doi = {https://doi.org/10.1088/0964-1726/25/7/075037} } |
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Mongardon, N., Kohlhauer, M., Lidouren, F., Hauet, T., Giraud, S., Hutin, A., Costes, B., Barau, C., Bruneval, P., Micheau, P., Cariou, A., Dhonneur, G., Berdeaux, A., Ghaleh, B. and Tissier, R. | A Brief Period of Hypothermia Induced by Total Liquid Ventilation Decreases End-Organ Damage and Multiorgan Failure Induced by Aortic Cross-Clamping | 2016 | Anesthesia and Analgesia Vol. 123(3), pp. 659-669 |
article | DOI URL |
Abstract: BACKGROUND: In animal models, whole-body cooling reduces end-organ injury after cardiac arrest and other hypoperfusion states. The benefits of cooling in humans, however, are uncertain, possibly because detrimental effects of prolonged cooling may offset any potential benefit. Total liquid ventilation (TLV) provides both ultrafast cooling and rewarming. In previous reports, ultrafast cooling with TLV potently reduced neurological injury after experimental cardiac arrest in animals. We hypothesized that a brief period of rapid cooling and rewarming via TLV could also mitigate multiorgan failure (MOF) after ischemia-reperfusion induced by aortic cross-clamping. METHODS: Anesthetized rabbits were submitted to 30 minutes of supraceliac aortic cross-clamping followed by 300 minutes of reperfusion. They were allocated either to a normothermic procedure with conventional ventilation (control group) or to hypothermic TLV (33°C) before, during, and after cross-clamping (pre-clamp, per-clamp, and post-clamp groups, respectively). In all TLV groups, hypothermia was maintained for 75 minutes and switched to a rewarming mode before resumption to conventional mechanical ventilation. End points included cardiovascular, renal, liver, and inflammatory parameters measured 300 minutes after reperfusion. RESULTS: In the normothermic (control) group, ischemia-reperfusion injury produced evidence of MOF including severe vasoplegia, low cardiac output, acute kidney injury, and liver failure. In the TLV group, we observed gradual improvements in cardiac output in post-clamp, per-clamp, and pre-clamp groups versus control (53 ± 8, 64 ± 12, and 90 ± 24 vs 36 ± 23 mL/min/kg after 300 minutes of reperfusion, respectively). Liver biomarker levels were also lower in pre-clamp and per-clamp groups versus control. However, acute kidney injury was prevented in pre-clamp, and to a limited extent in per-clamp groups, but not in the post-clamp group. For instance, creatinine clearance was 4.8 ± 3.1 and 0.5 ± 0.6 mL/kg/min at the end of the follow-up in pre-clamp versus control animals (P =.0004). Histological examinations of the heart, kidney, liver, and jejunum in TLV and control groups also demonstrated reduced injury with TLV. CONCLUSIONS: A brief period of ultrafast cooling with TLV followed by rapid rewarming attenuated biochemical and histological markers of MOF after aortic cross-clamping. Cardiovascular and liver dysfunctions were limited by a brief period of hypothermic TLV, even when started after reperfusion. Conversely, acute kidney injury was limited only when hypothermia was started before reperfusion. Further work is needed to determine the clinical significance of our results and to identify the optimal duration and timing of TLV-induced hypothermia for end-organ protection in hypoperfusion states. Copyright © 2016 International Anesthesia Research Society. | |||||
BibTeX:
@article{Mongardon2016659, author = {Mongardon, N. and Kohlhauer, M. and Lidouren, F. and Hauet, T. and Giraud, S. and Hutin, A. and Costes, B. and Barau, C. and Bruneval, P. and Micheau, P. and Cariou, A. and Dhonneur, G. and Berdeaux, A. and Ghaleh, B. and Tissier, R.}, title = {A Brief Period of Hypothermia Induced by Total Liquid Ventilation Decreases End-Organ Damage and Multiorgan Failure Induced by Aortic Cross-Clamping}, journal = {Anesthesia and Analgesia}, year = {2016}, volume = {123}, number = {3}, pages = {659-669}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84980332317&doi=10.1213%2fANE.0000000000001432&partnerID=40&md5=ea7a785b1d375fdd89881be8410888d9}, doi = {https://doi.org/10.1213/ANE.0000000000001432} } |
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Moreau, S., Laffay, P., Idier, A. and Atalla, N. | Several noise controls of the trailing-edge noise of a controlled-di usion airfoil | 2016 | 22nd AIAA/CEAS Aeroacoustics Conference, 2016 | conference | URL |
Abstract: This study presents several experiments with a reference and modified Controlled-Di usion (CD) airfoil in the anechoic wind-tunnel of Université de Sherbrooke. The control strategies are threefold: first a serrated trailing edge is considered; secondly a porous trailing edge; and finally a blown trailing edge. Acoustic, wall pressure and velocity measurements have been carried out for flow velocities from 10 to 40 m/s and for angles of attack from 0° to 14°. At low angle of attack, the far-field acoustic power spectral density of the reference airfoil is dominated by a primary tone with secondary tones, whereas at high angle of attack and high velocities it is mostly broadband. All control devices yield significant noise reduction of the tonal noise and the broadband noise over a large frequency range for certain flow conditions. © 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. | |||||
BibTeX:
@conference{Moreau2016, author = {Moreau, S. and Laffay, P. and Idier, A. and Atalla, N.}, title = {Several noise controls of the trailing-edge noise of a controlled-di usion airfoil}, journal = {22nd AIAA/CEAS Aeroacoustics Conference, 2016}, year = {2016}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84982943095&partnerID=40&md5=d3005301defee19b709bb4624292ec5e} } |
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Moriot, J., Quaegebeur, N., Le Duff, A. and Masson, P. | Characterization of the robustness of SHM imaging techniques using the absolute error of localization | 2016 | 8th European Workshop on Structural Health Monitoring, EWSHM 2016 Vol. 3, pp. 1762-1772 |
conference | URL |
Abstract: Guided waves-based imaging techniques have been studied for decades and have showed great potential for fast localization of defects on isotropic and anisotropic structures. In particular, pitch-catch techniques based on scattered waves allow inspection of large structures with a small number of actuators. In this paper, an approach is presented for characterizing the robustness of two imaging techniques for localizing a defect on an aluminium plate instrumented with three piezoelectric transducers, considering the absolute error of localization (AEL). This intuitive metric is useful for evaluating the probability of localization of a defect occurring on a structure where a critical zone is monitored. The robustness with respect to the distance between the transducers of the array and the level of noise in residual signals is studied. AEL values are mapped for several positions and sizes of the defect and a procedure for maximizing the ratio of correct localization over the grid is proposed. | |||||
BibTeX:
@conference{Moriot20161762, author = {Moriot, J. and Quaegebeur, N. and Le Duff, A. and Masson, P.}, title = {Characterization of the robustness of SHM imaging techniques using the absolute error of localization}, journal = {8th European Workshop on Structural Health Monitoring, EWSHM 2016}, year = {2016}, volume = {3}, pages = {1762-1772}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84995387788&partnerID=40&md5=21a96bea97f303dc5380167065652a9a} } |
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Nadeau, M., Sage, M., Kohlhauer, M., Vandamme, J., Mousseau, J., Robert, R., Tissier, R., Praud, J.-P., Walti, H. and Micheau, P. | Thermal Dynamics in Newborn and Juvenile Models Cooled by Total Liquid Ventilation | 2016 | IEEE Transactions on Biomedical Engineering Vol. 63(7), pp. 1483-1491 |
article | DOI URL |
Abstract: Total liquid ventilation (TLV) consists in filling the lungs with a perfluorocarbon (PFC) and using a liquid ventilator to ensure a tidal volume of oxygenated, CO2-free and temperature-controlled PFC. Having a much higher thermal capacity than air, liquid PFCs assume that the filled lungs become an efficient heat exchanger with pulmonary circulation. Objective: The objective of the present study was the development and validation of a parametric lumped thermal model of a subject in TLV. Methods: The lungs were modeled as one compartment in which the control volume varied as a function of the tidal volume. The heat transfer in the body was modeled as seven parallel compartments representing organs and tissues. The thermal model of the lungs and body was validated with two groups of lambs of different ages and weights (newborn and juvenile) undergoing an ultrafast mild therapeutic hypothermia induction by TLV. Results: The model error on all animals yielded a small mean error of-0.1 ± 0.4 °C for the femoral artery and 0.0 ± 0.1 °C for the pulmonary artery. Conclusion: The resulting experimental validation attests that the model provided an accurate estimation of the systemic arterial temperature and the venous return temperature. Significance: This comprehensive thermal model of the lungs and body has the advantage of closely modeling the rapid thermal dynamics in TLV. The model can explain how the time to achieve mild hypothermia between newborn and juvenile lambs remained similar despite of highly different physiological and ventilatory parameters. The strength of the model is its strong relationship with the physiological parameters of the subjects, which suggests its suitability for projection to humans. © 2015 IEEE. | |||||
BibTeX:
@article{Nadeau20161483, author = {Nadeau, M. and Sage, M. and Kohlhauer, M. and Vandamme, J. and Mousseau, J. and Robert, R. and Tissier, R. and Praud, J.-P. and Walti, H. and Micheau, P.}, title = {Thermal Dynamics in Newborn and Juvenile Models Cooled by Total Liquid Ventilation}, journal = {IEEE Transactions on Biomedical Engineering}, year = {2016}, volume = {63}, number = {7}, pages = {1483-1491}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84978039481&doi=10.1109%2fTBME.2015.2496938&partnerID=40&md5=1cfc43f03e4edd641374e9b98130ef0f}, doi = {https://doi.org/10.1109/TBME.2015.2496938} } |
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Nadeau, M., Sage, M., Praud, J.-P., Tissier, R., Walti, H. and Micheau, P. | Optimal control of inspired perfluorocarbon temperature for induction of hypothermia by total liquid ventilation in juvenile lamb model | 2016 | Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS Vol. 2016-October, pp. 2704-2707 |
conference | DOI URL |
Abstract: Mild hypothermia is well known for its therapeutic value in cardio- and neuroprotection. Many recent experimental studies have shown that the swiftness of the cooling offered by total liquid ventilation (TLV) holds great promise in achieving maximal therapeutic effect. TLV is an emerging ventilation technique in which the lungs are filled with breathable liquids, namely perfluorocarbons (PFCs). A liquid ventilator ensures subject ventilation by periodically renewing a volume of oxygenated, CO2-free and temperature-controlled breathable PFC. The substantial difference between breathing air and liquid is related to the fact that PFCs have over 500 times the volumetric thermal capacity of air 100% relative humidity. The PFC-filled lungs thus turn into an efficient heat exchanger with pulmonary circulation. The objective of the present study was to compute a posteriori the optimal inspired PFC temperature for ultrafast induction of mild hypothermia by TLV in a juvenile lamb experimentation using direct optimal control. The continuous time model and the discretized cycle-by-cycle model are presented. The control objectives of the direct optimal control are also presented and the results are compared with experimental data in order to validate the improved control performances. The computed direct optimal control showed that the inspired PFC temperature command can be improved to avoid temperature undershoots without altering the cooling performances. © 2016 IEEE. | |||||
BibTeX:
@conference{Nadeau20162704, author = {Nadeau, M. and Sage, M. and Praud, J.-P. and Tissier, R. and Walti, H. and Micheau, P.}, title = {Optimal control of inspired perfluorocarbon temperature for induction of hypothermia by total liquid ventilation in juvenile lamb model}, journal = {Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS}, year = {2016}, volume = {2016-October}, pages = {2704-2707}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85009121770&doi=10.1109%2fEMBC.2016.7591288&partnerID=40&md5=29b03eceff193d5e131d2cae2bd32f44}, doi = {https://doi.org/10.1109/EMBC.2016.7591288} } |
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O'Donoughue, P., Robin, O. and Berry, A. | Measuring the vibration response of plane panels under stationary and transient mechanical excitations using deflectometry | 2016 | Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future, pp. 615-621 | conference | URL |
Abstract: Deflectometry is a full-field optical technique that allows direct measurement of the slope fields on thin and plane structures submitted to static or time-varying loadings using a high-speed camera. The local slopes are derived from simple geometrical considerations and other relevant quantities such as deflections, curvatures and strains are then easily obtained. Compared to scanning laser vibrometry, commonly used to perform contactless vibration measurements, one key advantage gained with deflectometry is that the slopes at all measurement points are obtained simultaneously so that no scan operation is required. This has two major practical implications: measurement time is greatly reduced and non-stationary excitations can be studied. This communication will recall the main principles of the deflectometry technique and its experimental setup. Deflection measurement results on a plane panel will be presented under stationary (shaker) and transient (impact hammer) mechanical excitations. Application of deflectometry data to the identification of external forces will also be discussed. © 2016, German Acoustical Society (DEGA). All rights reserved. | |||||
BibTeX:
@conference{O'Donoughue2016615, author = {O'Donoughue, P. and Robin, O. and Berry, A.}, title = {Measuring the vibration response of plane panels under stationary and transient mechanical excitations using deflectometry}, journal = {Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future}, year = {2016}, pages = {615-621}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994666609&partnerID=40&md5=3b4008d8f9ce71c443a2acf4c8c3755b} } |
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Ostiguy, P.-C., Quaegebeur, N. and Masson, P. | Assessment of correlation-based imaging technique on composites | 2016 | 8th European Workshop on Structural Health Monitoring, EWSHM 2016 Vol. 2, pp. 1318-1327 |
conference | URL |
Abstract: In Structural Health Monitoring, the implementation of model-based imaging techniques regarding detection, positioning and sizing capabilities still poses a challenge for composite assemblies. Current techniques are limited by their model assumptions, that don't fully consider the effect of anisotropy on guided wave generation and propagation. This article presents the potential of a two-step procedure based on a correlation-based model, used both to identify the mechanical properties of a laminate and detect damage. The modelling of the wave generation is considered using the pin-force model, and the Global Matrix Method (GMM), based on the 3D elasticity theory, is used to model the wave propagation in a composite structures. The performance of the technique is first demonstrated numerically for a unidirectional laminate, and then experimentally for a unidirectional laminate. Results show the strong potential of such a technique for damage detection, even on substrates where the anisotropy has a strong effect on guided wave generation and propagation. | |||||
BibTeX:
@conference{Ostiguy20161318, author = {Ostiguy, P.-C. and Quaegebeur, N. and Masson, P.}, title = {Assessment of correlation-based imaging technique on composites}, journal = {8th European Workshop on Structural Health Monitoring, EWSHM 2016}, year = {2016}, volume = {2}, pages = {1318-1327}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994493619&partnerID=40&md5=360d70ccec68227609d05fff5276d56a} } |
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Padois, T., Doutres, O., Sgard, F. and Berry, A. | On the use of geometric and harmonic means with the generalized cross-correlation in the time domain to improve noise source maps | 2016 | Journal of the Acoustical Society of America Vol. 140(1) |
article | DOI URL |
Abstract: Microphone array techniques are an efficient tool to detect acoustic source positions. The delay and sum beamforming is the standard method. In the time domain, the generalized cross-correlation can be used to compute the noise source map. This technique is based on the arithmetic mean of the spatial likelihood functions. In this study, the classical arithmetic mean is replaced by the more standard generalized mean. The noise source maps provide by the arithmetic, geometric and harmonic means are compared in the case of numerical and experimental data obtained in a reverberant room. The geometric and harmonic means provide the best noise source maps with no side lobes and a better source level estimation. © 2016 Acoustical Society of America. | |||||
BibTeX:
@article{Padois2016, author = {Padois, T. and Doutres, O. and Sgard, F. and Berry, A.}, title = {On the use of geometric and harmonic means with the generalized cross-correlation in the time domain to improve noise source maps}, journal = {Journal of the Acoustical Society of America}, year = {2016}, volume = {140}, number = {1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84978252635&doi=10.1121%2f1.4955007&partnerID=40&md5=41bf6ba6b0804c295d974672a4902250}, doi = {https://doi.org/10.1121/1.4955007} } |
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Padois, T., Doutres, O., Sgard, F. and Berry, A. | Time domain source localization technique based on generalized cross correlation and generalized mean | 2016 | Canadian Acoustics - Acoustique Canadienne Vol. 44(3), pp. 60-61 |
article | URL |
Abstract: Delay And Sum (DAS) beamforming is implemented with the generalized cross correlation in the time domain. The influence of the number of microphones is investigated with numerical data in the case of a standard circular microphone array. Commonly, the Arithmetic Mean (AM) is used to average the spatial likelihood functions. In this study, the AM has been replaced by the Geometrical and Harmonic Mean (GM and HM). Two numerical cases involving a large or a small number of microphones were investigated. In each case, the GM and HM outperform the noise source map provided by the AM by removing the side lobes and narrowing the main lobe. Moreover, the GM and HM are less sensitive to the decrease of number of microphone as compared to the AM. | |||||
BibTeX:
@article{Padois201660, author = {Padois, T. and Doutres, O. and Sgard, F. and Berry, A.}, title = {Time domain source localization technique based on generalized cross correlation and generalized mean}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2016}, volume = {44}, number = {3}, pages = {60-61}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85002518054&partnerID=40&md5=531aec7c737444ffd57ba77505cbbfad} } |
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Quaegebeur, N., Masson, P., Beaudet, N. and Sarret, P. | Touchscreen Surface Based on Interaction of Ultrasonic Guided Waves with a Contact Impedance | 2016 | IEEE Sensors Journal Vol. 16(10), pp. 3564-3571 |
article | DOI URL |
Abstract: In this paper, a touchscreen device is proposed, based on guided-wave reflection and transmission induced by the presence of an object. The principle uses the advantages of other acoustic wave devices in terms of simplicity and applicability to any thin surface but is not subject to classical drawbacks (single touch, sensitivity to scratches or contaminant, and impossibility to follow motion of contact point). The theoretical interaction of guided waves with contact impedance is first derived in order to define the requirements of the sensor in terms of frequency range, mode, sensor type and location, and embedded electronics. Design criteria and experimental validation on a small prototype (200 × 250mm) are proposed to demonstrate the potential of the approach for simple, robust, and reliable contact detection of pointlike or extended objects for consumer electronics or biomedical applications. © 2001-2012 IEEE. | |||||
BibTeX:
@article{Quaegebeur20163564, author = {Quaegebeur, N. and Masson, P. and Beaudet, N. and Sarret, P.}, title = {Touchscreen Surface Based on Interaction of Ultrasonic Guided Waves with a Contact Impedance}, journal = {IEEE Sensors Journal}, year = {2016}, volume = {16}, number = {10}, pages = {3564-3571}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84963811334&doi=10.1109%2fJSEN.2016.2535386&partnerID=40&md5=7bb174f27483acefa28d6af782531f48}, doi = {https://doi.org/10.1109/JSEN.2016.2535386} } |
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Quaegebeur, N., Padois, T., Gauthier, P.-A. and Masson, P. | Enhancement of time-domain acoustic imaging based on generalized cross-correlation and spatial weighting | 2016 | Mechanical Systems and Signal Processing Vol. 75, pp. 515-524 |
article | DOI URL |
Abstract: In this paper, an alternative formulation of the time-domain beamforming is proposed using the generalized cross-correlation of measured signals. This formulation uses spatial weighting functions adapted to microphone positions and imaging points. The proposed approach is demonstrated for acoustic source localization using a microphone array, both theoretically and experimentally. An increase in accuracy of acoustic imaging results is shown for both narrow and broadband sources, while a factor of reduction up to 20 in the computation time can be achieved, allowing real-time or volumetric source localization over very large grids. © 2016 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Quaegebeur2016515, author = {Quaegebeur, N. and Padois, T. and Gauthier, P.-A. and Masson, P.}, title = {Enhancement of time-domain acoustic imaging based on generalized cross-correlation and spatial weighting}, journal = {Mechanical Systems and Signal Processing}, year = {2016}, volume = {75}, pages = {515-524}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959226556&doi=10.1016%2fj.ymssp.2015.12.012&partnerID=40&md5=943edb56b0bf818ae397d760d7ac45c7}, doi = {https://doi.org/10.1016/j.ymssp.2015.12.012} } |
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Robin, O., Amedin, C., Berry, A., Atalla, N., Doutres, O. and Sgard, F. | A Numerical Study of a Method for Estimating Sound Absorption Coefficient under a Synthesized Diffuse Acoustic Field | 2016 | SAE International Journal of Passenger Cars - Mechanical Systems Vol. 9(3) |
article | DOI URL |
Abstract: A method for estimating the sound absorption coefficient of a material under a synthesized Diffuse Acoustic Field was recently proposed, as an alternative to classical sound absorption measurements in reverberant rooms (Robin O., Berry A., Doutres O., Atalla N., ‘Measurement of the absorption coefficient of absorbing materials under a synthesized diffuse acoustic field’, J. Acoust. Soc. Am., 136 (1) EL13-EL19, 2014). Using sound field reproduction approaches and a synthetic array of acoustic monopoles facing the material, estimation of the sound absorption coefficient under a reproduced Diffuse Acoustic Field in a hemi-anechoic room was shown to be feasible. The method was successfully tested on a few samples of melamine foam of close thicknesses and areas, but the influence of several parameters such as the source height, or the samples dimensions together with the nature of the porous material was not fully investigated. In this paper, the robustness of the method is numerically studied by examining the influence of the aforementioned parameters on the estimated sound absorption coefficient, with various square samples of homogeneous materials and a synthetic array of fixed dimensions. The principle of the method will be first recalled, and the main results of these numerical experiments will be then reported. Copyright © 2016 SAE International. | |||||
BibTeX:
@article{Robin2016, author = {Robin, O. and Amedin, C.K. and Berry, A. and Atalla, N. and Doutres, O. and Sgard, F.}, title = {A Numerical Study of a Method for Estimating Sound Absorption Coefficient under a Synthesized Diffuse Acoustic Field}, journal = {SAE International Journal of Passenger Cars - Mechanical Systems}, year = {2016}, volume = {9}, number = {3}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988813549&doi=10.4271%2f2016-01-1847&partnerID=40&md5=3a7c98f3faea8929011699b4e2fa5685}, doi = {https://doi.org/10.4271/2016-01-1847} } |
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Robin, O., Chazot, J.-D., Boulandet, R., Michau, M., Berry, A. and Atalla, N. | A plane and thin panel with representative simply supported boundary conditions for laboratory vibroacoustic tests | 2016 | Acta Acustica united with Acustica Vol. 102(1), pp. 170-182 |
article | DOI URL |
Abstract: A technique to setup a simply supported rectangular plane panel for laboratory vibroacoustic tests is described and validated. For a given panel fixed to thin vertical supports, a dimensionless parameter is proposed to size these supports following a desired frequency precision compared to theoretical eigenfrequencies of a panel with such boundary conditions. A numerical study confirms the potential of this design parameter. Detailed instructions for assembling a panel with adequate thin vertical supports on a rigid frame are then given. Finally, three laboratory cases are described which illustrate possible experimental vibroacoustic applications using a panel assembled following previous guidelines. The design parameter viability is experimentally confirmed, and all obtained results depicted good agreement with analytical solutions and numerical predictions. | |||||
BibTeX:
@article{Robin2016170, author = {Robin, O. and Chazot, J.-D. and Boulandet, R. and Michau, M. and Berry, A. and Atalla, N.}, title = {A plane and thin panel with representative simply supported boundary conditions for laboratory vibroacoustic tests}, journal = {Acta Acustica united with Acustica}, year = {2016}, volume = {102}, number = {1}, pages = {170-182}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958206592&doi=10.3813%2fAAA.918934&partnerID=40&md5=f7d844b1a19505214dce1b776dc32b8f}, doi = {https://doi.org/10.3813/AAA.918934} } |
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Robin, O. and Berry, A. | Alternative methods for the measurement of panel transmission loss under diffuse acoustic field excitation | 2016 | Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future, pp. 3349-3358 | conference | URL |
Abstract: Three different approaches are described that aim at providing alternative transmission loss measurements to standards, either using a classical coupled room arrangement or a different laboratory installation. The first one consists in reproducing a random excitation at a panel surface using a synthetic array approach, needing only a single monopole source in hemi-anechoic conditions. This approach removes the need of a reverberant room to generate a diffuse acoustic field excitation, and allows estimating the panel behaviour under other random excitations such as a turbulent boundary layer. The two others possibilities describes transmission loss estimations in a standard reverberant-anechoic rooms arrangement, but using 'single quantity' measurements. The transmission loss is first derived using sound intensity measurements only, performed as an insertion loss test (radiated and incident sound intensity are measured when a panel is installed or not). The transmission loss is then derived using vibration measurements only. The virtual fields method allows identifying the parietal pressure field exciting the panel and estimating the corresponding incident acoustic power, while the radiated acoustic power is calculated using the radiation resistance matrix method. For the three approaches, results for a small aluminium panel and a large composite panel are provided, illustrating their respective potentials. © 2016, German Acoustical Society (DEGA). All rights reserved. | |||||
BibTeX:
@conference{Robin20163349, author = {Robin, O. and Berry, A.}, title = {Alternative methods for the measurement of panel transmission loss under diffuse acoustic field excitation}, journal = {Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future}, year = {2016}, pages = {3349-3358}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994662772&partnerID=40&md5=3ea24ccfd9308f5d5f66c166cfdbc880} } |
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Robin, O., Amedin, C., Berry, A., Atalla, N., Doutres, O. and Sgard, F. | Sound absorption measurements: Comparison of standard tests in reverberant room with measurements using a synthetized diffuse acoustic field | 2016 | Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future, pp. 4139-4148 | conference | URL |
Abstract: This communication mainly aims at providing a comprehensive comparison of measurements of sound absorption coefficients performed following standard in a reverberant room and using a synthetized Diffuse Acoustic Field. Using sound field reproduction approaches and a synthetic array of acoustic monopoles facing a material, estimation of the sound absorption coefficient under a reproduced Diffuse Acoustic Field in a hemi-anechoic room was previously shown to be feasible. Five different acoustic materials are tested. Melamine foam is used as a reference case, while the other four are utilized in the building industry: fiberglass batts, heavy-density fiberglass boards, polyurethane foam and ceiling tiles. Results obtained following standards, a synthetized diffuse field and also theoretical predictions assuming materials of infinite extent are compared. It is shown that the sound absorbing coefficients under a diffuse acoustic field excitation can be estimated with satisfactory accuracy using the synthetic diffuse field approach. The sample area is significantly reduced compared to standard requirements and a reverberant room is no longer needed. The effect of the source height and of the array source density on obtained results is also briefly investigated using FEM calculations. Possible improvements of the method at low frequency are finally discussed. © 2016, German Acoustical Society (DEGA). All rights reserved. | |||||
BibTeX:
@conference{Robin20164139, author = {Robin, O. and Amedin, C.K. and Berry, A. and Atalla, N. and Doutres, O. and Sgard, F.}, title = {Sound absorption measurements: Comparison of standard tests in reverberant room with measurements using a synthetized diffuse acoustic field}, journal = {Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future}, year = {2016}, pages = {4139-4148}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994644473&partnerID=40&md5=3ada055ff16f98f2a6b586f3e7331cef} } |
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Robin, O., De Rosa, S. and Berry, A. | Similitudes for the structural response and radiated power from plates | 2016 | Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future, pp. 5421-5430 | conference | URL |
Abstract: This communication investigates exact and distorted similitudes and the related scaling laws for the analysis of both dynamic response and radiated power of rectangular plates. The response of a given panel in similitude from another one is determined from a generalization of the modal approach, allowing the use of mode shapes, natural frequencies and finally radiation functions in order to establish appropriate scaling laws. Analytical models of simply supported rectangular plates are first used to produce both original, replica and distorted model responses under point mechanical excitation. Laboratory experiments are then performed on two baffled simply supported aluminum panels (a reference and one in exact similitude) under shaker excitation. All obtained results show that structural response or radiated power of a given plate can be both recovered with satisfactory accuracy by using the related scaling laws, even if parent models are used. Interestingly, the radiated power can be nevertheless quite well estimated even if the local structural response is not perfectly reconstructed. Even preliminary, these investigations show good potentialities for the estimation of radiation properties of panels using similitude concepts. © 2016, German Acoustical Society (DEGA). All rights reserved. | |||||
BibTeX:
@conference{Robin20165421, author = {Robin, O. and De Rosa, S. and Berry, A.}, title = {Similitudes for the structural response and radiated power from plates}, journal = {Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future}, year = {2016}, pages = {5421-5430}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994626569&partnerID=40&md5=715345039df7d27b54ad2a3f5db8c919} } |
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Sacristan, C., Dupont, T., Sicot, O., Leclaire, P., Verdière, K., Panneton, R. and Gong, X. | A mixture approach to the acoustic properties of a macroscopically inhomogeneous porous aluminum in the equivalent fluid approximation | 2016 | Journal of the Acoustical Society of America Vol. 140(4), pp. 2847-2855 |
article | DOI URL |
Abstract: The acoustic properties of an air-saturated macroscopically inhomogeneous aluminum foam in the equivalent fluid approximation are studied. A reference sample built by forcing a highly compressible melamine foam with conical shape inside a constant diameter rigid tube is studied first. In this process, a radial compression varying with depth is applied. With the help of an assumption on the compressed pore geometry, properties of the reference sample can be modelled everywhere in the thickness and it is possible to use the classical transfer matrix method as theoretical reference. In the mixture approach, the material is viewed as a mixture of two known materials placed in a patchwork configuration and with proportions of each varying with depth. The properties are derived from the use of a mixing law. For the reference sample, the classical transfer matrix method is used to validate the experimental results. These results are used to validate the mixture approach. The mixture approach is then used to characterize a porous aluminium for which only the properties of the external faces are known. A porosity profile is needed and is obtained from the simulated annealing optimization process. © 2016 Acoustical Society of America. | |||||
BibTeX:
@article{Sacristan20162847, author = {Sacristan, C.J. and Dupont, T. and Sicot, O. and Leclaire, P. and Verdière, K. and Panneton, R. and Gong, X.L.}, title = {A mixture approach to the acoustic properties of a macroscopically inhomogeneous porous aluminum in the equivalent fluid approximation}, journal = {Journal of the Acoustical Society of America}, year = {2016}, volume = {140}, number = {4}, pages = {2847-2855}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053361618&doi=10.1121%2f1.4965300&partnerID=40&md5=7801e42964f6014f42bdc529d1d85577}, doi = {https://doi.org/10.1121/1.4965300} } |
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Sage, M., Nadeau, M., Kohlhauer, M., Praud, J.-P., Tissier, R., Robert, R., Walti, H. and Micheau, P. | Effect of ultra-fast mild hypothermia using total liquid ventilation on hemodynamics and respiratory mechanics | 2016 | Cryobiology Vol. 73(1), pp. 99-101 |
article | DOI URL |
Abstract: Ultra-fast cooling for mild therapeutic hypothermia (MTH) has several potential applications, including prevention of post-cardiac arrest syndrome. Ultra-fast MTH by total liquid ventilation (TLV) entails the sudden filling of the lungs with a cold perfluorocarbon liquid and its subsequent use to perform TLV. The present physiological study was aimed at assessing whether pulmonary and systemic hemodynamics as well as lung mechanics are significantly altered during this procedure. Pulmonary and systemic arterial pressures, cardiac output as well as airway resistance and respiratory system compliance were measured during ultra-fast MTH by TLV followed by rewarming and normothermia in six healthy juvenile lambs. Results show that none of the studied variables were altered upon varying the perfluorocarbon temperature from 12 to 41 °C. It is concluded that ultra-fast MTH by TLV does not have any deleterious effect on hemodynamics or lung mechanics in healthy juvenile lambs. © 2016 Elsevier Inc. | |||||
BibTeX:
@article{Sage201699, author = {Sage, M. and Nadeau, M. and Kohlhauer, M. and Praud, J.-P. and Tissier, R. and Robert, R. and Walti, H. and Micheau, P.}, title = {Effect of ultra-fast mild hypothermia using total liquid ventilation on hemodynamics and respiratory mechanics}, journal = {Cryobiology}, year = {2016}, volume = {73}, number = {1}, pages = {99-101}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84973855975&doi=10.1016%2fj.cryobiol.2016.05.009&partnerID=40&md5=acd4431c48019bf3f47636b3037d4849}, doi = {https://doi.org/10.1016/j.cryobiol.2016.05.009} } |
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Sherafat, M., Guitel, R., Quaegebeur, N., Lessard, L., Hubert, P. and Masson, P. | Guided wave scattering behavior in composite bonded assemblies | 2016 | Composite Structures Vol. 136, pp. 696-705 |
article | DOI URL |
Abstract: Composite bonded joints are prone to disbond when submitted to fatigue or extreme loads. The objective of this paper is to evaluate the integrity of a composite skin-stringer joint using the scattering behavior of the Lamb waves. The structure of interest is composed of three carbon fiber reinforced polymer (CFRP) plates bonded together by adhesive film as a typical representative of skin-stringer assembly. Two different bonding conditions are investigated for the joint: undamaged and damaged (with disbond). A circular disbond is introduced into the joint using Teflon tape during manufacturing. Two co-localized rectangular piezoceramics are used to generate plane guided waves at 180° and 135° incidence. A non-contact measurement is performed using a 3-D Laser Doppler Vibrometer (LDV) to extract the required information for evaluation of bonding condition. The results present the different scattered field of the guided waves at the joint as a function of frequency, mode, excitation angle and presence of artificial damage. It was found that the amplitude and directivity patterns of scattered fields are affected by the presence of damage, such that SHM design guidelines can be derived for efficient damage detection in the composite skin-stringer bonded joints. © 2015 Elsevier Ltd. | |||||
BibTeX:
@article{Sherafat2016696, author = {Sherafat, M.H. and Guitel, R. and Quaegebeur, N. and Lessard, L. and Hubert, P. and Masson, P.}, title = {Guided wave scattering behavior in composite bonded assemblies}, journal = {Composite Structures}, year = {2016}, volume = {136}, pages = {696-705}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84947209946&doi=10.1016%2fj.compstruct.2015.10.046&partnerID=40&md5=7d910d2f059a3b57281d1d5936392ab9}, doi = {https://doi.org/10.1016/j.compstruct.2015.10.046} } |
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Sherafat, M., Guitel, R., Quaegebeur, N., Hubert, P., Lessard, L. and Masson, P. | Structural health monitoring of a composite skin-stringer assembly using within-the-bond strategy of guided wave propagation | 2016 | Materials and Design Vol. 90, pp. 787-794 |
article | DOI URL |
Abstract: The objective of this paper is to investigate the within-the-bond guided wave propagation in a composite skin-stringer joint. The structure of interest is composed of three carbon fibre reinforced polymer (CFRP) plates bonded together by adhesive film. This bonded joint is prone to disbond when submitted to extreme loads or fatigue. Therefore, two bonding conditions are investigated, namely undamaged and damaged (with disbond). The artificial disbond is introduced into the joint using a circular Teflon tape during manufacturing. Two co-localized slender rectangular piezoceramics are used to generate plane guided waves within-the-bondlines and non-contact measurement is performed using a 3-D laser Doppler vibrometer (LDV) to extract the required information for evaluation of the bonding conditions. The results include reflection, transmission and also scattering of the guided waves at the joint as a function of frequency, propagating mode and presence of artificial damage. It was found that the amplitude of the reflection, transmission coefficients and directivity patterns of scattered waves are affected by the presence of damage, such that Structural Health Monitoring (SHM) design guidelines can be derived for efficient damage detection in the composite assemblies using a within-the-bond inspection strategy. © 2015 Elsevier Ltd. | |||||
BibTeX:
@article{Sherafat2016787, author = {Sherafat, M.H. and Guitel, R. and Quaegebeur, N. and Hubert, P. and Lessard, L. and Masson, P.}, title = {Structural health monitoring of a composite skin-stringer assembly using within-the-bond strategy of guided wave propagation}, journal = {Materials and Design}, year = {2016}, volume = {90}, pages = {787-794}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84952361298&doi=10.1016%2fj.matdes.2015.11.018&partnerID=40&md5=ce9a40ba93fb7991a067a2b74d13a336}, doi = {https://doi.org/10.1016/j.matdes.2015.11.018} } |
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Sherafat, M., Quaegebeur, N., Hubert, P., Lessard, L. and Masson, P. | Finite element modeling of Lamb wave propagation in composite stepped joints | 2016 | Journal of Reinforced Plastics and Composites Vol. 35(10), pp. 796-806 |
article | DOI URL |
Abstract: The objective of this research is to evaluate the integrity of a composite bonded joint by simulating Lamb wave propagation using finite element methods. The structure of interest is composed of two stepped carbon fiber reinforced polymer plates bonded together by an adhesive film. Two different bonding conditions are examined for the joint: undamaged and damaged (with disbond). In the finite element model, an antisymmetric guided wave is excited by imposing an out-of-plane displacement on the surfaces and a spatial Fourier transform is performed before and after the bond line for extraction of reflection and transmission coefficients. For validation, experiments are also conducted using two colocalized rectangular piezoceramics for plane wave generation. A 3D laser Doppler vibrometer is employed for noncontact measurement of the in-plane and out-of-plane velocity. The results confirm the reflections from the steps' edges, and it is found that the level of reflection and transmission of the guided wave mode is different for undamaged and damaged joints. The antisymmetric mode in the pulse-echo configuration seems to be an efficient mode and strategy for disbond detection in composite repairs. The results verify that guided wave propagation is very effective for disbond detection in composite bonded joints and scarf repairs. © SAGE Publications. | |||||
BibTeX:
@article{Sherafat2016796, author = {Sherafat, M.H. and Quaegebeur, N. and Hubert, P. and Lessard, L. and Masson, P.}, title = {Finite element modeling of Lamb wave propagation in composite stepped joints}, journal = {Journal of Reinforced Plastics and Composites}, year = {2016}, volume = {35}, number = {10}, pages = {796-806}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84965183499&doi=10.1177%2f0731684416629763&partnerID=40&md5=c4bf45b2bee653ce8b6a493e79cf65e7}, doi = {https://doi.org/10.1177/0731684416629763} } |
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Thomas, C. and Atalla, N. | Optimization of Noise Control Treatments for Aircraft's Sidewalls | 2016 | SAE Technical Papers Vol. 2016-June(June) |
article | DOI URL |
Abstract: In passenger aircraft the most important noise control treatment is the primary insulation attached to the fuselage. Next to its acoustic properties the primary insulation main purpose is the thermal insulation and the minimization of condensed water. In general it consists of fibrous materials like glass wool wrapped in a thin foil. Due to stringent flame, smoke and toxicity requirements the amount of available materials is limited. Furthermore the amount of material installed in aircraft per year is much smaller compared to needs in the automotive industry. Therefore the best lay-up of the available materials is needed in terms of acoustics. This paper presents a tool for numerical optimization of the sound insulation package. To find an improved insulation the simulation tool is used in interaction with a measurement database. The databank is constructed from aircraft grade materials such as fibrous materials, foams, resistive screens and impervious heavy layers. The database includes as well materials new to the aircraft industry to check if the acoustic potential justifies a new material qualification. The tool enables as well the optimization for different frequency ranges as well as for single wall or double wall configurations depending on the fuselage section. Typical constraints are the overall thickness and the weight. Results will be illustrated for different optimization strategies Copyright © 2016 SAE International. | |||||
BibTeX:
@article{Thomas2016, author = {Thomas, C. and Atalla, N.}, title = {Optimization of Noise Control Treatments for Aircraft's Sidewalls}, journal = {SAE Technical Papers}, year = {2016}, volume = {2016-June}, number = {June}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84978077181&doi=10.4271%2f2016-01-1850&partnerID=40&md5=386080d9e4ae6ccf1c187553d1c31b96}, doi = {https://doi.org/10.4271/2016-01-1850} } |
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Verdière, K., Panneton, R. and Elkoun, S. | Prediction of the acoustic behavior of a parallel assembly of hollow cylinders | 2016 | Applied Acoustics Vol. 102, pp. 100-107 |
article | DOI URL |
Abstract: In this paper, an approach to predict the sound absorption coefficient and sound transmission loss of a parallel assembly of hollow cylinders is presented. This approach is based on image processing and the Parallel Transfer Matrix Method (PTMM) using four Johnson-Champoux-Allard effective fluids. First, effective parameters of each fluid are identified using geometrical considerations and numerical simulations. Then, the approach is validated for a stack of uniform plastic straws, and used to model a natural stack of non-uniform switchgrass straws. Finally, two parametric studies are conducted to evaluate the effects of the geometric parameters of the straws on the acoustic behavior of their stack. It is shown that there are optimal parameters that maximize the acoustic behavior at specific frequencies. © 2015 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Verdière2016100, author = {Verdière, K. and Panneton, R. and Elkoun, S.}, title = {Prediction of the acoustic behavior of a parallel assembly of hollow cylinders}, journal = {Applied Acoustics}, year = {2016}, volume = {102}, pages = {100-107}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84943554323&doi=10.1016%2fj.apacoust.2015.09.016&partnerID=40&md5=334e134100ae882b1a2d99674b698009}, doi = {https://doi.org/10.1016/j.apacoust.2015.09.016} } |
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Alimonti, L. and Atalla, N. | A hybrid finite element-transfer matrix method for the modeling of vibroacoustic systems with attached noise control treatment | 2015 | INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering | conference | URL |
Abstract: This paper is concerned with the development of a hybrid methodology to speed up finite element analysis in vibroacoustic applications. The approach aims at avoiding the finite element modeling of the noise control treatment, which is cumbersome from both computational (i.e. model size) and virtual prototyping (i.e. meshing) standpoints. A transfer matrix model is instead employed, allowing for a reduction of the computational burden and a substantial simplification of the multilayer modeling. The methodology relies on the assumption that the noise control treatment is flat, homogeneous and of infinite lateral extent (i.e. finite size effects are negligible). The latter hypothesis is justified by short wavelength and high dissipation. Under these circumstances, the surface impedance at the two ends of the laterally unbounded noise control treatment can be formally obtained starting from an integral formulation. Results prove that, generally speaking, the hybrid finite element-transfer matrix model can always capture the qualitative behavior of the vibroacoustic system. However, it is shown that, in some cases, finite size effects within the noise control treatment may be important. Hence, a correction is proposed to retrieve the missing performance. © 2015 by ASME. | |||||
BibTeX:
@conference{Alimonti2015, author = {Alimonti, L. and Atalla, N.}, title = {A hybrid finite element-transfer matrix method for the modeling of vibroacoustic systems with attached noise control treatment}, journal = {INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84947579328&partnerID=40&md5=b79ff9988ceff5e9000a6add2279cf35} } |
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Alimonti, L., Atalla, N., Berry, A. and Sgard, F. | A hybrid finite element-transfer matrix model for vibroacoustic systems with flat and homogeneous acoustic treatments | 2015 | Journal of the Acoustical Society of America Vol. 137(2), pp. 976-988 |
article | DOI URL |
Abstract: Practical vibroacoustic systems involve passive acoustic treatments consisting of highly dissipative media such as poroelastic materials. The numerical modeling of such systems at low to mid frequencies typically relies on substructuring methodologies based on finite element models. Namely, the master subsystems (i.e., structural and acoustic domains) are described by a finite set of uncoupled modes, whereas condensation procedures are typically preferred for the acoustic treatments. However, although accurate, such methodology is computationally expensive when real life applications are considered. A potential reduction of the computational burden could be obtained by approximating the effect of the acoustic treatment on the master subsystems without introducing physical degrees of freedom. To do that, the treatment has to be assumed homogeneous, flat, and of infinite lateral extent. Under these hypotheses, simple analytical tools like the transfer matrix method can be employed. In this paper, a hybrid finite element-transfer matrix methodology is proposed. The impact of the limiting assumptions inherent within the analytical framework are assessed for the case of plate-cavity systems involving flat and homogeneous acoustic treatments. The results prove that the hybrid model can capture the qualitative behavior of the vibroacoustic system while reducing the computational effort. © 2015 Acoustical Society of America. | |||||
BibTeX:
@article{Alimonti2015976, author = {Alimonti, L. and Atalla, N. and Berry, A. and Sgard, F.}, title = {A hybrid finite element-transfer matrix model for vibroacoustic systems with flat and homogeneous acoustic treatments}, journal = {Journal of the Acoustical Society of America}, year = {2015}, volume = {137}, number = {2}, pages = {976-988}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923353699&doi=10.1121%2f1.4907163&partnerID=40&md5=6665b7272a9706020a8a94f5e640e25c}, doi = {https://doi.org/10.1121/1.4907163} } |
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Bélanger, A., Jean-Sébastien, D. and Masson, P. | Experimental characterization of a meso-scale combustion driven actuator designed for high efficiency | 2015 | Proceedings of the ASME Design Engineering Technical Conference Vol. 9 |
conference | DOI URL |
Abstract: Meso-scale power systems (10 W to 1000 W) are needed to power untethered mobile robots and assisting devices such as powered exoskeletons. Air-breathing combustion driven actuators, used in a direct acting manner, can be used for such applications and take advantage of the high power density of fluidic actuators and the high energy density of chemical fuels. However, fuel-To-mechanical energy conversion efficiency is critical to make such chemical systems viable over electrical systems. This paper presents the efficiency-based design and experimental characterization of two combustion driven actuators intended to reach high specific power and specific energy. First, efficiency oriented design principles are derived from internal combustion engine theory: (1) an ideal-cycle thermodynamic model of a generic constant volume combustion system suggests that compression ratio and the expansion/compression ratio should both be maximized, and (2) the practical effects of heat, mass and friction losses as well as fuel choice in a small scale combustion chamber context are discussed. Second, two simplified prototypes are built and tested. The first prototype uses a rolling diaphragm seal to limit the effect of mass and friction losses. The second prototype consists of a standard air cylinder that minimizes heat losses by reducing the surface-To-volume ratio of the combustion chamber. Hydrogen is selected as fuel because it allows lean combustion which limits the effect of heat loss with low combustion temperatures. Compression ratio and equivalence ratio are varied experimentally to evaluate their effect on efficiency. Experimental results demonstrate an energy conversion efficiency of 15.3% at a compression ratio of 4.15 and a low equivalence ratio of 0.3. Ragone analysis of relevant meso-scale power systems for mobile robotic suggest that, with proper optimization and system integration, combustion driven power systems can become a viable solution for lightweight and long range meso-scale robotic applications. © Copyright 2015 by ASME. | |||||
BibTeX:
@conference{Bélanger2015, author = {Bélanger, A. and Jean-Sébastien, D. and Masson, P.P.}, title = {Experimental characterization of a meso-scale combustion driven actuator designed for high efficiency}, journal = {Proceedings of the ASME Design Engineering Technical Conference}, year = {2015}, volume = {9}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84978958218&doi=10.1115%2fDETC2015-47845&partnerID=40&md5=4da8d9660d031153942657e5dd9b4ef3}, doi = {https://doi.org/10.1115/DETC2015-47845} } |
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Boisvert, M., Micheau, P., Mammosser, D. and Nadeau, J. | Real Time Evaluation of the Driver Ability to Recover Energy during Braking, by Observing the Slip Ratio of the Powered Wheels, on an Electric Vehicle | 2015 | 2015 IEEE Vehicle Power and Propulsion Conference, VPPC 2015 - Proceedings | conference | DOI URL |
Abstract: This article is about a new method to evaluate the ability of the pilot to recover energy during the regenerative braking period. In order to optimize the amount of energy recovered from electrical braking, most of the existing literatures present optimal methods which consist in defining the optimal braking torque as a function of vehicle speed. The originality of the present study is to propose a new strategy based on the observation of the powered wheel slip. It has been proved that regenerative braking based on a slip controller was less affected by the majority of the parametric changes [1], including the type of road. This method proposes to evaluate the pilot by observing the slip ratio instead of the applied torque. Thus, the optimal engine torque is reduced when the pilot is on a slippery road. Thereby the pilot evaluation is possible in all road conditions. © 2015 IEEE. | |||||
BibTeX:
@conference{Boisvert2015, author = {Boisvert, M. and Micheau, P. and Mammosser, D. and Nadeau, J.}, title = {Real Time Evaluation of the Driver Ability to Recover Energy during Braking, by Observing the Slip Ratio of the Powered Wheels, on an Electric Vehicle}, journal = {2015 IEEE Vehicle Power and Propulsion Conference, VPPC 2015 - Proceedings}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962786136&doi=10.1109%2fVPPC.2015.7353003&partnerID=40&md5=3a4134b29a01369a5b3145ecc5a341e6}, doi = {https://doi.org/10.1109/VPPC.2015.7353003} } |
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Boisvert, M., Micheau, P. and Nadeau, J. | Nonlinear LQG slip controller based on an empirical model for a three wheel hybrid vehicle | 2015 | 2014 IEEE Vehicle Power and Propulsion Conference, VPPC 2014 | conference | DOI URL |
Abstract: A three wheels recreational vehicle propelled by its unique rear wheel is studied for the purpose of regenerative braking control. To ensure the stability of the vehicle and the safety of the pilot, the slip ratio of the powered wheel must be limited during regenerative braking. In this study, a design of a LQG slip tracking algorithm is proposed. The non-linear model is based on experimental tests and the controller has been validated by simulations and road tests. © 2014 IEEE. | |||||
BibTeX:
@conference{Boisvert2015, author = {Boisvert, M. and Micheau, P. and Nadeau, J.}, title = {Nonlinear LQG slip controller based on an empirical model for a three wheel hybrid vehicle}, journal = {2014 IEEE Vehicle Power and Propulsion Conference, VPPC 2014}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84934300206&doi=10.1109%2fVPPC.2014.7007110&partnerID=40&md5=519bf2bdf23fb232dae5fdca09a117cd}, doi = {https://doi.org/10.1109/VPPC.2014.7007110} } |
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Boisvert, M. and Micheau, P. | Wheel slip controller for the regenerative braking of electric vehicle: Experimental results with a three wheels recreational hybrid vehicle | 2015 | 2015 10th International Conference on Ecological Vehicles and Renewable Energies, EVER 2015 | conference | DOI URL |
Abstract: In any hybrid or electrical vehicle, the electric motor can be used as an electric generator to impose a negative torque to the wheel providing the braking effect by recovering part of the kinetic energy used for charging the batteries. The main hypothesis of this study is to propose that a slip control is preferable to a braking torque control during the regenerative braking. The experimental results obtained with a three wheel recreational electric vehicle validate that the wheel slip control is an efficient regenerative braking strategy to ensure both the optimal energy recovery and the wheel adherence in spite of road uncertainties. © 2015 European Union. | |||||
BibTeX:
@conference{Boisvert2015, author = {Boisvert, M. and Micheau, P.}, title = {Wheel slip controller for the regenerative braking of electric vehicle: Experimental results with a three wheels recreational hybrid vehicle}, journal = {2015 10th International Conference on Ecological Vehicles and Renewable Energies, EVER 2015}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84943391347&doi=10.1109%2fEVER.2015.7112944&partnerID=40&md5=c38265d56d97eb748caa07f7e4bc7ad4}, doi = {https://doi.org/10.1109/EVER.2015.7112944} } |
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Boisvert, M., Micheau, P. and Mammosser, D. | Simulated and experimental comparisons of slip and torque control strategies for regenerative braking in instances of parametric uncertainties | 2015 | Journal of Robotics and Mechatronics Vol. 27(3), pp. 235-243 |
article | URL |
Abstract: A three-wheel hybrid recreational vehicle was studied for the purpose of regenerative braking control. In order to optimize the amount of energy recovered from electrical braking, most of the existing literature presents optimal methods which consist in defining the optimal braking torque as a function of vehicle speed. The originality of the present study is to propose a new strategy based on the control of rear wheel slip. A simulator based on MATLAB/Simulink and validated with experimental measurements compared the two strategies and their sensitivities to variations in mass, slope and road conditions. Numerical simulations and experimental tests show that regenerative braking based on a slip controller was less affected by the majority of the parametric changes. Moreover, since the slip was limited, the longitudinal stability of the vehicle was thereby improved. It thus becomes possible to ensure optimal energy recovery and vehicle stability even in instances of parametric uncertainties. © 2015, Fuji Technology Press. All rights reserved. | |||||
BibTeX:
@article{Boisvert2015235, author = {Boisvert, M. and Micheau, P. and Mammosser, D.}, title = {Simulated and experimental comparisons of slip and torque control strategies for regenerative braking in instances of parametric uncertainties}, journal = {Journal of Robotics and Mechatronics}, year = {2015}, volume = {27}, number = {3}, pages = {235-243}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937880674&partnerID=40&md5=d55630fc4b7263fa642d7b3c8d119de0} } |
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Champoux, Y., Vanwallenghem, J. and Drouet, J.-M. | Dynamic calibration of an instrumented bike brake hood in measuring power absorbed by the hands | 2015 | Procedia Engineering Vol. 112, pp. 225-230 |
conference | DOI URL |
Abstract: One of the most significant factors in ride quality in cycling sports are the vibrations generated by road surface defects passing through the bicycle and transmitted to the cyclist's hands and buttocks. To study comfort, one metric that has been put forward is the measurement of the power absorbed at the cyclist's hands. Measuring absorbed power requires the use of the force and the velocity at the hands and provides an overall energy-based quantity. The aim of this study is to dynamically calibrate an instrumented brake hood transducer to measure the power absorbed at the cyclist's hands. Using a base excitation technique involving suspended masses, dynamic calibration of the brake hood was conducted in the 3-100 Hz frequency range, and the force transducer sensitivity and seismic mass were measured. An accelerometer attached to the brake hood enabled measurements of acceleration and calculation of velocity. A frequency-dependent phase mismatch between the force signal and the acceleration was obtained by measuring the accelerance at the hand-bike interface. A device called the Power Calibrator equipped with an impedance head was developed to assess the accuracy of the power measured by the instrumented brake hood. The results show that the instrumented brake hood can accurately measure the absorbed power at the cyclist's hands. Phase mismatch between the force and the velocity signals must be corrected to improve the accuracy of measurements. To implement the measurements, it is recommended that the calculations be done in the frequency domain. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. | |||||
BibTeX:
@conference{Champoux2015225, author = {Champoux, Y. and Vanwallenghem, J. and Drouet, J.-M.}, title = {Dynamic calibration of an instrumented bike brake hood in measuring power absorbed by the hands}, journal = {Procedia Engineering}, year = {2015}, volume = {112}, pages = {225-230}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945582793&doi=10.1016%2fj.proeng.2015.07.204&partnerID=40&md5=89d639aa27d8d48c391eb16fff38799f}, doi = {https://doi.org/10.1016/j.proeng.2015.07.204} } |
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Cherif, R. and Atalla, N. | Experimental investigation of the accuracy of a vibroacoustic model for sandwich-composite panels | 2015 | Journal of the Acoustical Society of America Vol. 137(3), pp. 1541-1550 |
article | DOI URL |
Abstract: This paper presents a detailed experimental validation of a general laminate model to predict the vibroacoustic behavior of flat sandwich-composite panels. The accuracy of the model is investigated using a thin and a thick sandwich panel over a large frequency band. Several indicators are compared including the structural wavenumber, modal density, damping loss factor, radiation efficiency, and sound transmission loss. The accuracy of a simpler model based on identifying effective properties of an equivalent orthotropic panel from the General Laminate Model is also discussed. Results show that the vibroacoustic behaviors of flat sandwich-composite panels are accurately estimated using the used model and compare well to the equivalent panel model (for total transmission loss). This experimental investigation is generic and can be used as a benchmark to validate other sandwich models. © 2015 Acoustical Society of America. | |||||
BibTeX:
@article{Cherif20151541, author = {Cherif, R. and Atalla, N.}, title = {Experimental investigation of the accuracy of a vibroacoustic model for sandwich-composite panels}, journal = {Journal of the Acoustical Society of America}, year = {2015}, volume = {137}, number = {3}, pages = {1541-1550}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84925263202&doi=10.1121%2f1.4908239&partnerID=40&md5=a152dcfe7e93193e231b59a816ad6706}, doi = {https://doi.org/10.1121/1.4908239} } |
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Cherif, R. and Atalla, N. | Measurement of the radiation efficiency of complex structures | 2015 | Noise Control Engineering Journal Vol. 63(4), pp. 339-346 |
article | DOI URL |
Abstract: This paper investigates the measurement of the radiation efficiency of complex structures with two constructions: metallic (flat and stiffened aluminum panels) and sandwich composite (honeycomb core). Two measurement methods are compared. The first is direct and is based on the simultaneous measurement of the vibration and acoustic response of the freely hanged structure in an anechoic room. The second is indirect and uses a statistical energy analysis (SEA) based model of the test article freely hanged in a reverberant room. For the latter two implementations are compared. The first is based on the SEA formulation, when only the test article is excited. The second is an inverse technique based on the SEA formulation, when both the test article and the reverberant room are excited. All methods are compared to analytical or numerical predictions. Results show that the experimental radiations efficiencies are in good agreement with theory for the studied constructions, especially when the inverse SEA method is used. © 2015 Institute of Noise Control Engineering. | |||||
BibTeX:
@article{Cherif2015339, author = {Cherif, R. and Atalla, N.}, title = {Measurement of the radiation efficiency of complex structures}, journal = {Noise Control Engineering Journal}, year = {2015}, volume = {63}, number = {4}, pages = {339-346}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84942895011&doi=10.3397%2f1%2f376330&partnerID=40&md5=765a67fedbaa3f0c5624360f7411bd14}, doi = {https://doi.org/10.3397/1/376330} } |
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Cherif, R., Chazot, J.-D. and Atalla, N. | Damping loss factor estimation of two-dimensional orthotropic structures from a displacement field measurement | 2015 | Journal of Sound and Vibration Vol. 356, pp. 61-71 |
article | DOI URL |
Abstract: Abstract This paper presents a damping loss factor estimation method of two-dimensional orthotropic structures. The method is based on a scanning laser vibrometer measurement. The dispersion curves of the studied structures are first estimated at several chosen angles of propagation with a spatial Fourier transform. Next the global damping loss factor is evaluated with the proposed inverse wave method. The method is first tested using numerical results obtained from a finite element model. The accuracy of the proposed method is then experimentally investigated on an isotropic aluminium panel and two orthoropic sandwich composite panels with a honeycomb core. The results are finally compared and validated over a large frequency band with classical methods such as the half-power bandwidth method (3 dB method), the decay rate method and the steady-state power input method. The present method offers the possibility of structural characterization with a simple measurement scan. © 2015 Elsevier Ltd. | |||||
BibTeX:
@article{Cherif201561, author = {Cherif, R. and Chazot, J.-D. and Atalla, N.}, title = {Damping loss factor estimation of two-dimensional orthotropic structures from a displacement field measurement}, journal = {Journal of Sound and Vibration}, year = {2015}, volume = {356}, pages = {61-71}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938740434&doi=10.1016%2fj.jsv.2015.06.042&partnerID=40&md5=5a2262025cc44fccb144990c29701b60}, doi = {https://doi.org/10.1016/j.jsv.2015.06.042} } |
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Doutres, O., Atalla, N. and Osman, H. | Transfer matrix modeling and experimental validation of cellular porous material with resonant inclusions | 2015 | Journal of the Acoustical Society of America Vol. 137(6), pp. 3502-3513 |
article | DOI URL |
Abstract: Porous materials are widely used for improving sound absorption and sound transmission loss of vibrating structures. However, their efficiency is limited to medium and high frequencies of sound. A solution for improving their low frequency behavior while keeping an acceptable thickness is to embed resonant structures such as Helmholtz resonators (HRs). This work investigates the absorption and transmission acoustic performances of a cellular porous material with a two-dimensional periodic arrangement of HR inclusions. A low frequency model of a resonant periodic unit cell based on the parallel transfer matrix method is presented. The model is validated by comparison with impedance tube measurements and simulations based on both the finite element method and a homogenization based model. At the HR resonance frequency (i) the transmission loss is greatly improved and (ii) the sound absorption of the foam can be either decreased or improved depending on the HR tuning frequency and on the thickness and properties of the host foam. Finally, the diffuse field sound absorption and diffuse field sound transmission loss performance of a 2.6 m2 resonant cellular material are measured. It is shown that the improvements observed at the Helmholtz resonant frequency on a single cell are confirmed at a larger scale. © 2015 Acoustical Society of America. | |||||
BibTeX:
@article{Doutres20153502, author = {Doutres, O. and Atalla, N. and Osman, H.}, title = {Transfer matrix modeling and experimental validation of cellular porous material with resonant inclusions}, journal = {Journal of the Acoustical Society of America}, year = {2015}, volume = {137}, number = {6}, pages = {3502-3513}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84934965465&doi=10.1121%2f1.4921027&partnerID=40&md5=df47bf7650f3289fbf04fe742be3aa80}, doi = {https://doi.org/10.1121/1.4921027} } |
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Dupont, T., Verdière, K., Leclaire, P. and Panneton, R. | A method to control the lateral boundary condition effects in the characterization of acoustic materials in an impedance tube | 2015 | INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering | conference | URL |
Abstract: The measurements of acoustic indicators and transfer matrix in an acoustic tube are strongly dependent upon controlling the lateral boundary conditions of the sample. The objective is to propose an experimental method that can control the lateral boundary effects in the acoustic characterization of material when it is tested in an acoustic tube. A transfer matrix method involving parallel assemblies of materials (P-TMM) was recently proposed. The present study suggests measuring in a tube the transfer matrix of a special patchwork, which helps to control the lateral boundary conditions of the sample or to control the first frame resonance frequency. The patchwork is composed of a sample of material and of host elements which are known "a priori" (air or rigid and impervious elements). With the help of the transfer matrix of the host elements, the P-TMM is applied in a reverse way in order to deduce the transfer matrix of the sample of material. We suggest three patchwork configurations to control the acoustic behavior of a sample: A sample with a rigid and impervious inclusion; a sample with a cross-section smaller than the tube's cross-section; and a sample with a host support composed of a rigid ring with lateral nails. © 2015 by ASME. | |||||
BibTeX:
@conference{Dupont2015, author = {Dupont, T. and Verdière, K. and Leclaire, P. and Panneton, R.}, title = {A method to control the lateral boundary condition effects in the characterization of acoustic materials in an impedance tube}, journal = {INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84947566231&partnerID=40&md5=16f241b0cc1323678272303a871a397b} } |
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Floquet, J., Désilets, M., Micheau, P. and Quaegebeur, N. | Development of ultrasonic thickness measurements of solidification front inside metallurgical reactors | 2015 | Mechanics and Industry Vol. 16(1) |
article | DOI URL |
Abstract: The corrosive molten salts used for aluminum electrolysis attack the walls of the electrochemical reactors, reducing their lifetime and increasing production costs. Fortunately, a ledge is formed on those walls by the solidification of the molten salts used as the electrolytic bath, due to the heat losses through the sides of the reactors. This ledge is essential, protecting the sidewalls from the corrosive effect of the bath. Its thickness must however be controlled to avoid a reduction of the efficiency caused by a partial reduction of the electrolysis surface. One challenge is to measure the ledge thickness inside operating cells. The originality of this work resides in the development of an ultrasonic device to provide a non-intrusive ledge thickness measurement. Experimental results are obtained on a specially developed setup using the proposed ultrasonic device and are compared to ledge thicknesses obtained with an intrusive probe. The ultrasonic thickness measurement concept is validated up to 950°C with a satisfactory accuracy inside 6 mm of the intrusive measurement. © AFM, EDP Sciences 2014. | |||||
BibTeX:
@article{Floquet2015, author = {Floquet, J. and Désilets, M. and Micheau, P. and Quaegebeur, N.}, title = {Development of ultrasonic thickness measurements of solidification front inside metallurgical reactors}, journal = {Mechanics and Industry}, year = {2015}, volume = {16}, number = {1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921495438&doi=10.1051%2fmeca%2f2014070&partnerID=40&md5=36e387b2cc0815fb10d35a8704da143d}, doi = {https://doi.org/10.1051/meca/2014070} } |
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Gauthier, P.-A., Camier, C., Padois, T., Pasco, Y. and Berry, A. | Sound field reproduction of real flight recordings in aircraft cabin mock-up | 2015 | AES: Journal of the Audio Engineering Society Vol. 63(1-2), pp. 6-20 |
article | URL |
Abstract: Sound environment reproduction of various flight conditions in an aircraft mock-up is a valuable tool for the study, prediction, demonstration, and jury testing of interior aircraft sound quality. To provide a faithful reproduced sound environment, time, frequency, and spatial characteristics should be preserved as much as possible. Physical sound field reproduction approaches for spatial sound reproduction are mandatory to immerse the listener's body in the proper sound field so that localization cues are recreated. For sound field reproduction inside cabin mock-up, the reported approach relies on multichannel equalization using least-meansquare formulation. In this paper a modified multichannel equalization procedure is proposed to simplify the selection of the regularization amount. The paper presents physical evaluations of reproduced sound fields on the basis of real flight recordings using an 80-channel microphone array and 41 reproduction sources in the cabin mock-up. Physical evaluations of reproduced spatial sound distributions are also provided on the basis of acoustic source maps obtained from acoustic imaging. © 2015 J. Audio Eng. Soc. | |||||
BibTeX:
@article{Gauthier20156, author = {Gauthier, P.-A. and Camier, C. and Padois, T. and Pasco, Y. and Berry, A.}, title = {Sound field reproduction of real flight recordings in aircraft cabin mock-up}, journal = {AES: Journal of the Audio Engineering Society}, year = {2015}, volume = {63}, number = {1-2}, pages = {6-20}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84922575930&partnerID=40&md5=b8785c5fb750d1a1f81fdd54610ad98f} } |
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Gérard, A., Moreau, S., Berry, A. and Masson, P. | Design of multi-modal obstruction to control tonal fan noise using modulation principles | 2015 | Journal of Sound and Vibration Vol. 356, pp. 34-47 |
article | DOI URL |
Abstract: Abstract The approach presented in this paper uses a combination of obstructions in the upstream flow of subsonic axial fans with B blades to destructively interfere with the primary tonal noise at the blade passage frequency. The first step of the proposed experimental method consists in identifying the independent radiation of B-1 and B lobed obstructions at the control microphones. During this identification step, rotating obstructions allow for the frequencies of primary and secondary tonal noise to be slightly shifted in the spectrum due to modulation principles. The magnitude of the secondary tonal noise generated by each obstruction can be adjusted by varying the size of the lobes of the obstruction, and the phase of the secondary tonal noise is related to the angular position of the obstruction. The control obstructions are then optimized by combining the B-1 and B lobed obstructions to significantly reduce the acoustic power at blade passage frequency. © 2015 Elsevier Ltd. | |||||
BibTeX:
@article{Gérard201534, author = {Gérard, A. and Moreau, S. and Berry, A. and Masson, P.}, title = {Design of multi-modal obstruction to control tonal fan noise using modulation principles}, journal = {Journal of Sound and Vibration}, year = {2015}, volume = {356}, pages = {34-47}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938741514&doi=10.1016%2fj.jsv.2015.06.003&partnerID=40&md5=d9e6208db5dc8f95eeaf014c475ae374}, doi = {https://doi.org/10.1016/j.jsv.2015.06.003} } |
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Ghaffari Mosanenzadeh, S., Naguib, H., Park, C. and Atalla, N. | Design and development of novel bio-based functionally graded foams for enhanced acoustic capabilities | 2015 | Journal of Materials Science Vol. 50(3), pp. 1248-1256 |
article | DOI URL |
Abstract: Development of a super sound absorbing fixture to damp acoustic energy of sound wave over a wide range of frequencies, while occupying the least amount of space is of great interest to various industries. A broadband absorption effect can be achieved by appropriately grading the cell structure of a porous layer to enhance acoustic properties based on the specific application. Such porous structures with microstructural gradation are called functionally graded materials. A novel graded bio-based foam structure is presented with enhanced sound absorption capability compared to uniform foams of the same porosity with 20 % increase of maximum acoustic absorption coefficient and 9 % increase in average absorption. In addition, foams with different cell sizes and cell distributions were fabricated and characterized for acoustic and mechanical performance to investigate the effect of microstructure of open-cell foams on the macroscopic properties. Among the uniformly distributed cells, cell size of 380 µm illustrates the highest average absorption. The correspondence between sound absorption of open-cell foams under study to cell size indicates the importance of understanding the effect of microstructure on acoustic behavior of porous-condensed matter to determine the ideal cell size/arrangement and reach the engineering design with optimum performance for any specific application. © 2014, Springer Science+Business Media New York. | |||||
BibTeX:
@article{GhaffariMosanenzadeh20151248, author = {Ghaffari Mosanenzadeh, S. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {Design and development of novel bio-based functionally graded foams for enhanced acoustic capabilities}, journal = {Journal of Materials Science}, year = {2015}, volume = {50}, number = {3}, pages = {1248-1256}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988253883&doi=10.1007%2fs10853-014-8681-6&partnerID=40&md5=18214e0de8110f486b868d879b65de3a}, doi = {https://doi.org/10.1007/s10853-014-8681-6} } |
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Ghaffari Mosanenzadeh, S., Doutres, O., Naguib, H., Park, C. and Atalla, N. | A numerical scheme for investigating the effect of bimodal structure on acoustic behavior of polylactide foams | 2015 | Applied Acoustics Vol. 88, pp. 75-83 |
article | DOI URL |
Abstract: In order to understand the acoustic behavior of porous membranes, there is a need to further investigate the link between microstructure and macroscopic properties of such materials. This study presents the sound absorption properties of a novel bimodal foam structure made of polylactide (PLA) with an interconnected network of pores and micropores of very different characteristic sizes, fabricated utilizing the blend of PLA and polyethylene glycol (PEG) water soluble polymer. Fabricated foams are bio-based and have the advantage of resolving the environmental concerns raised by petrochemical based sound absorbers. The purpose of this study is to develop bio-based open cell structures as a practical solution to today's needs for noise control resolutions. Acoustic performance of the bimodal PLA foams is studied by measuring the normal incident absorption coefficient and the effect of bimodal structure is investigated in terms of acoustic properties (i.e., sound absorption) and non-acoustic properties associated to the Johnson-Champoux-Allard model (i.e., porosity, airflow resistivity, tortuosity, ...). Inverse method based on JCA model and impedance tube measurements for normal incident absorption coefficient was applied to estimate tortuosity and characteristic lengths. Results of inverse method are in good agreement with direct measurements of normal incident absorption coefficient. While tortuosity increases by increasing the polymer weight percent, it remains constant as the secondary porous structure extends in the porous medium. As the bimodal structure extends through the foam, both thermal and viscous characteristic lengths increase for different foam categories. © 2014 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{GhaffariMosanenzadeh201575, author = {Ghaffari Mosanenzadeh, S. and Doutres, O. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {A numerical scheme for investigating the effect of bimodal structure on acoustic behavior of polylactide foams}, journal = {Applied Acoustics}, year = {2015}, volume = {88}, pages = {75-83}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908405696&doi=10.1016%2fj.apacoust.2014.08.011&partnerID=40&md5=d9fcc61f1f39d03d7c7f16e1bbf7caaa}, doi = {https://doi.org/10.1016/j.apacoust.2014.08.011} } |
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Kandil, M., Micheau, P., Trovao, J., Bakay, L. and Dubois, M. | Hybrid Magnetic Bearing Regulation via Super Twisting Control | 2015 | ICCAS 2015 - 2015 15th International Conference on Control, Automation and Systems, Proceedings, pp. 1566-1571 | conference | DOI URL |
Abstract: A homopolar permanent magnet-biased magnetic bearing is a suitable solution to reduce power losses in active magnetic bearing systems. This configuration is complex due to the coupling between the coil-created magnetic fluxes and permanent magnet fluxes, besides being inherently a nonlinear, unstable, and multivariable system. One of the most recent topics in variable structure theory is represented by the higher order sliding modes (HOSM). In this paper, we propose the application of super twisting controller (STC) for the double loop robust stabilization of a rigid rotor horizontally supported by radial hybrid magnetic bearings. The efficiency of the applied controller is demonstrated via simulations in the presence of harmonic disturbances like vibration forces. © 2015 Institute of Control, Robotics and Systems - ICROS. | |||||
BibTeX:
@conference{Kandil20151566, author = {Kandil, M.S. and Micheau, P. and Trovao, J.P. and Bakay, L.S. and Dubois, M.R.}, title = {Hybrid Magnetic Bearing Regulation via Super Twisting Control}, journal = {ICCAS 2015 - 2015 15th International Conference on Control, Automation and Systems, Proceedings}, year = {2015}, pages = {1566-1571}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84966440577&doi=10.1109%2fICCAS.2015.7364606&partnerID=40&md5=68820c72111e2311e3ba208400df3306}, doi = {https://doi.org/10.1109/ICCAS.2015.7364606} } |
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Kohlhauer, M., Lidouren, F., Remy-Jouet, I., Mongardon, N., Adam, C., Bruneval, P., Hocini, H., Levy, Y., Blengio, F., Carli, P., Vivien, B., Ricard, J.-D., Micheau, P., Walti, H., Nadeau, M., Robert, R., Richard, V., Mulder, P., Maresca, D., Demené, C., Pernot, M., Tanter, M., Ghaleh, B., Berdeaux, A. and Tissier, R. | Hypothermic total liquid ventilation is highly protective through cerebral hemodynamic preservation and sepsis-like mitigation after asphyxial cardiac arrest | 2015 | Critical Care Medicine Vol. 43(10), pp. e420-e430 |
article | DOI URL |
Abstract: Objectives: Total liquid ventilation provides ultrafast and potently neuro- and cardioprotective cooling after shockable cardiac arrest and myocardial infarction in animals. Our goal was to decipher the effect of hypothermic total liquid ventilation on the systemic and cerebral response to asphyxial cardiac arrest using an original pressure- and volume-controlled ventilation strategy in rabbits. Design: Randomized animal study. Setting: Academic research laboratory. Subjects: New Zealand Rabbits. Interventions: Thirty-six rabbits were submitted to 13 minutes of asphyxia, leading to cardiac arrest. After resumption of spontaneous circulation, they underwent either normothermic life support (control group, n = 12) or hypothermia induced by either 30 minutes of total liquid ventilation (total liquid ventilation group, n = 12) or IV cold saline (conventional cooling group, n = 12). Measurements and Main Results: Ultrafast cooling with total liquid ventilation (32°C within 5 min in the esophagus) dramatically attenuated the post-cardiac arrest syndrome regarding survival, neurologic dysfunction, and histologic lesions (brain, heart, kidneys, liver, and lungs). Final survival rate achieved 58% versus 0% and 8% in total liquid ventilation, control, and conventional cooling groups (p < 0.05), respectively. This was accompanied by an early preservation of the blood-brain barrier integrity and cerebral hemodynamics as well as reduction in the immediate reactive oxygen species production in the brain, heart, and kidneys after cardiac arrest. Later on, total liquid ventilation also mitigated the systemic inflammatory response through alteration of monocyte chemoattractant protein-1, interleukin-1â, and interleukin-8 transcripts levels compared with control. In the conventional cooling group, cooling was achieved more slowly (32°C within 90-120 min in the esophagus), providing none of the above-mentioned systemic or organ protection. Conclusions: Ultrafast cooling by total liquid ventilation limits the post-cardiac arrest syndrome after asphyxial cardiac arrest in rabbits. This protection involves an early limitation in reactive oxidative species production, blood-brain barrier disruption, and delayed preservation against the systemic inflammatory response. Copyright © 2015 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved. | |||||
BibTeX:
@article{Kohlhauer2015e420, author = {Kohlhauer, M. and Lidouren, F. and Remy-Jouet, I. and Mongardon, N. and Adam, C. and Bruneval, P. and Hocini, H. and Levy, Y. and Blengio, F. and Carli, P. and Vivien, B. and Ricard, J.-D. and Micheau, P. and Walti, H. and Nadeau, M. and Robert, R. and Richard, V. and Mulder, P. and Maresca, D. and Demené, C. and Pernot, M. and Tanter, M. and Ghaleh, B. and Berdeaux, A. and Tissier, R.}, title = {Hypothermic total liquid ventilation is highly protective through cerebral hemodynamic preservation and sepsis-like mitigation after asphyxial cardiac arrest}, journal = {Critical Care Medicine}, year = {2015}, volume = {43}, number = {10}, pages = {e420-e430}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941919511&doi=10.1097%2fCCM.0000000000001160&partnerID=40&md5=bcf7b403a6b5104fd50f51521d75e48c}, doi = {https://doi.org/10.1097/CCM.0000000000001160} } |
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Leclaire, P., Umnova, O., Dupont, T. and Panneton, R. | Acoustical properties of air-saturated porous material with periodically distributed dead-end pores | 2015 | Journal of the Acoustical Society of America Vol. 137(4), pp. 1772-1782 |
article | DOI URL |
Abstract: A theoretical and numerical study of the sound propagation in air-saturated porous media with straight main pores bearing lateral cavities (dead-ends) is presented. The lateral cavities are located at "nodes" periodically spaced along each main pore. The effect of periodicity in the distribution of the lateral cavities is studied, and the low frequency limit valid for the closely spaced dead-ends is considered separately. It is shown that the absorption coefficient and transmission loss are influenced by the viscous and thermal losses in the main pores as well as their perforation rate. The presence of long or short dead-ends significantly alters the acoustical properties of the material and can increase significantly the absorption at low frequencies (a few hundred hertz). These depend strongly on the geometry (diameter and length) of the dead-ends, on their number per node, and on the periodicity along the propagation axis. These effects are primarily due to low sound speed in the main pores and to thermal losses in the dead-end pores. The model predictions are compared with experimental results. Possible designs of materials of a few cm thicknesses displaying enhanced low frequency absorption at a few hundred hertz are proposed. © 2015 Acoustical Society of America. | |||||
BibTeX:
@article{Leclaire20151772, author = {Leclaire, P. and Umnova, O. and Dupont, T. and Panneton, R.}, title = {Acoustical properties of air-saturated porous material with periodically distributed dead-end pores}, journal = {Journal of the Acoustical Society of America}, year = {2015}, volume = {137}, number = {4}, pages = {1772-1782}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84929094157&doi=10.1121%2f1.4916712&partnerID=40&md5=d7627b49f1b656a9b989010aed501732}, doi = {https://doi.org/10.1121/1.4916712} } |
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Lecomte, P., Gauthier, P.-A., Langrenne, C., Garcia, A. and Berry, A. | On the use of a lebedev grid for ambisonics | 2015 | 139th Audio Engineering Society International Convention, AES 2015 | conference | URL |
Abstract: Ambisonics provide tools for three-dimensional sound field analysis and synthesis. The theory is based on sound field decomposition using a truncated basis of spherical harmonics. For the three-dimensional problem the decomposition of the sound field as well as the synthesis imply an integration over the sphere which respects the orthonormality of the spherical harmonics. This integration is practically achieved with discrete angular samples over the sphere. This paper investigates spherical sampling using a Lebedev grid for practical applications of Ambisonics. The paper presents underlying theory, simulations of reconstructed sound field and examples of actual prototypes using a 50 nodes grid able to perform recording and reconstruction up to order 5. Orthonormality errors are provided up to sixth order and compared for two grids: 1) the Lebedev grid with 50 nodes and 2) the Pentakis-Dodecahedron with 32 nodes. Finally, the paper presents some practical advantages using Lebedev grids for Ambisonics, in particular the use of sub-grids working up to order 1 or 3 and sharing common nodes with the 50 nodes grid. | |||||
BibTeX:
@conference{Lecomte2015, author = {Lecomte, P. and Gauthier, P.-A. and Langrenne, C. and Garcia, A. and Berry, A.}, title = {On the use of a lebedev grid for ambisonics}, journal = {139th Audio Engineering Society International Convention, AES 2015}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84983161987&partnerID=40&md5=555e166af540b71f836e263aef8bc0e6} } |
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Lecomte, P. and Gauthier, P.-A. | Real-time 3D ambisonics using faust, processing, pure data, and OSC | 2015 | DAFx 2015 - Proceedings of the 18th International Conference on Digital Audio Effects | conference | URL |
Abstract: This paper presents several digital signal processing (DSP) tools for the real-time synthesis of a 3D sound pressure field using Ambisonics technologies. The spatialization of monophonic signal or the reconstruction of natural 3D recorded sound pressure fields is considered. The DSP required to generate the loudspeaker signals is implemented using the FAUST programming language. FAUST enables and simplifies the compilation of the developed tools on several architectures and on different DSP tool format. In this paper, a focus is made on the near-field filters implementation which allows for the encoding of spherical waves with distance information. The gain variation with distance is also taken into account. The control of the synthesis can be made by software controllers or hardware controllers, such as joystick, by the mean of PURE DATA and OPEN SOUND CONTROL (OSC) messages. A visual feedback tool using the PROCESSING programming language is also presented in the most recent implementation. The aim of this research derives from a larger research project on physically-accurate sound field reproduction for simulators in engineering and industrial applications. | |||||
BibTeX:
@conference{Lecomte2015, author = {Lecomte, P. and Gauthier, P.-A.}, title = {Real-time 3D ambisonics using faust, processing, pure data, and OSC}, journal = {DAFx 2015 - Proceedings of the 18th International Conference on Digital Audio Effects}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85030174558&partnerID=40&md5=13d0320519e82edaa2e504d31e8f60ae} } |
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Lépine, J., Champoux, Y. and Drouet, J.-M. | The relative contribution of road bicycle components on vibration induced to the cyclist | 2015 | Sports Engineering Vol. 18(2), pp. 79-91 |
article | DOI URL |
Abstract: Improving comfort in road bicycle design is a paramount concern for cyclists, who are affected by the vibrations caused by constant contact with the road surface. The cycling community has deployed many efforts in the attempt to understand and improve bicycle comfort. However, these attempts have been focused on specific components such as the fork, frame and wheels without knowing their relative influence on vibration induced to the bicyclist (VIB). The objective of this paper is to assess the relative contribution of bicycle components on the VIB at the cyclist’s hands and buttocks. A factorial design test comparing the VIB in acceleration, force and power of different bicycle components has already shown that the handlebar and fork are the preponderant components for the VIB measured at the cyclist’s hands. At the buttocks, the preponderant components are the wheels and frame. © 2014, International Sports Engineering Association. | |||||
BibTeX:
@article{Lépine201579, author = {Lépine, J. and Champoux, Y. and Drouet, J.-M.}, title = {The relative contribution of road bicycle components on vibration induced to the cyclist}, journal = {Sports Engineering}, year = {2015}, volume = {18}, number = {2}, pages = {79-91}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939940815&doi=10.1007%2fs12283-014-0168-9&partnerID=40&md5=c0c746d572e0c6d59c27b2ceb8766ed2}, doi = {https://doi.org/10.1007/s12283-014-0168-9} } |
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Magne, S., Moreau, S. and Berry, A. | Subharmonic tonal noise from backflow vortices radiated by a low-speed ring fan in uniform inlet flow | 2015 | Journal of the Acoustical Society of America Vol. 137(1), pp. 228-237 |
article | DOI URL |
Abstract: In order to highlight the mechanisms responsible for subharmonic tonal noise, a complete aeroacoustic study of a ring fan in presence of a uniform inlet flow is conducted. Unsteady RANS simulations with a compressible flow solver are used to compute the flow field and identify the acoustic sources on the rotor. The tip clearance recirculation shows upstream vortices that impinge the rotor blades and create the main source of unsteadiness on the fan. Since these vortices rotate at a lower speed than the rotor, the frequency of the impact is lower than the blade passing frequency. The acoustic signature is computed by propagating the noise sources located on the rotor surfaces using two methods: A Ffowcs-Williams and Hawkings analogy in the time-domain and an analytical model in the frequency-domain based on the compact rotating dipole formulation. A comparison with experimental results confirms that the aeroacoustic phenomena responsible for the subharmonic tonal noise are well captured and properly propagated by the acoustic codes. © 2015 Acoustical Society of America. | |||||
BibTeX:
@article{Magne2015228, author = {Magne, S. and Moreau, S. and Berry, A.}, title = {Subharmonic tonal noise from backflow vortices radiated by a low-speed ring fan in uniform inlet flow}, journal = {Journal of the Acoustical Society of America}, year = {2015}, volume = {137}, number = {1}, pages = {228-237}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923822871&doi=10.1121%2f1.4904489&partnerID=40&md5=73309d3a30bf56ce0b776c610cea2be2}, doi = {https://doi.org/10.1121/1.4904489} } |
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Masson, P., Atalla, N., Berry, A., Champoux, Y., Micheau, P. and Panneton, R. | Unique resources for research and development in acoustics and vibration at Groupe d'Acoustique de l'Université de Sherbrooke (GAUS) | 2015 | Canadian Acoustics - Acoustique Canadienne Vol. 43(2), pp. 40-41 |
article | URL |
Abstract: This paper presents the human resources and infrastructure available at Groupe d'Acoustique de l'Université de Sherbrooke (GAUS) located in Sherbrooke, QC, for research and development in acoustics. GAUS was founded by Jean Nicolas in 1984 and is now recognized worldwide as one of the leading research groups in acoustics and vibration, with a team of around 60 people. The expertise, infrastructure and examples of applications of the work conducted are shown in this paper. © 2015, Canadian Acoustical Association. All rights reserved. | |||||
BibTeX:
@article{Masson201540, author = {Masson, P. and Atalla, N. and Berry, A. and Champoux, Y. and Micheau, P. and Panneton, R.}, title = {Unique resources for research and development in acoustics and vibration at Groupe d'Acoustique de l'Université de Sherbrooke (GAUS)}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2015}, volume = {43}, number = {2}, pages = {40-41}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85002896506&partnerID=40&md5=5caab8949641908a7a27807f163802df} } |
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Mejdi, A., Atalla, N. and Ghinet, S. | Wave spectral finite element model for the prediction of sound transmission loss and damping of sandwich panels | 2015 | Computers and Structures Vol. 158, pp. 251-258 |
article | DOI URL |
Abstract: Abstract Sandwich panels are usually modeled by considering only asymmetric motion which assumes the core deforms by transversal shearing without any compressive deformation over the thickness. This assumption is acceptable for panels with relatively stiff and thin cores. However, symmetric motion becomes important when the core is thick or soft. Under such conditions, the compressive deformation over the core thickness becomes significant. This paper addresses the prediction of the Sound Transmission Loss (STL) and composite Damping Loss Factor (DLF) of sandwich panels with either thin or thick cores as well as stiff or soft (viscoelastic) cores. Both the skin and the core are assumed to be orthotropic. A spectral finite element based approach is developed wherein the stress and strain components in each layer are described using the properties in that layer for a forced trace wave number and heading direction. The proposed approach provides a reliable and numerically efficient tool to account for the compressive deformation effect of thick orthotropic sandwich layers. Moreover, the proposed model is also able to consider panels with multiple of layers with varying properties. © 2015 Elsevier Ltd. | |||||
BibTeX:
@article{Mejdi2015251, author = {Mejdi, A. and Atalla, N. and Ghinet, S.}, title = {Wave spectral finite element model for the prediction of sound transmission loss and damping of sandwich panels}, journal = {Computers and Structures}, year = {2015}, volume = {158}, pages = {251-258}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84933567685&doi=10.1016%2fj.compstruc.2015.06.014&partnerID=40&md5=ec1c355d897c0f4e57e8408297a91db8}, doi = {https://doi.org/10.1016/j.compstruc.2015.06.014} } |
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Michau, M., Berry, A., Micheau, P. and Herzog, P. | Optimal virtual mechanical impedances for the vibroacoustic active control of a thin plate | 2015 | Journal of the Acoustical Society of America Vol. 137(1), pp. 199-207 |
article | DOI URL |
Abstract: In order to reduce the acoustic power radiated by a flexible panel, dual colocated actuator / sensor pairs are used to modify its vibration. The control strategy implemented for harmonic disturbances leads to locally impose a virtual mechanical impedance to the structure, using the linear relation between the actuator input and the control output of each pair. This virtual mechanical impedance is computed in order to minimize the radiated acoustic power. The proposed approach consists in two steps: (1) the matrix of optimal virtual mechanical impedance is calculated by measuring the primary disturbance and the transfer functions between actuators and structural/acoustic sensors and (2) the virtual mechanical impedance objective is achieved using a real-time integral controller. It is shown that such an optimal control approach leads to better sound power reduction than a classical active damping strategy where the virtual mechanical impedance is defined as real positive. Theoretical and experimental results are compared, also showing that the method proposed here is robust regarding variations of the primary disturbance. © 2015 Acoustical Society of America. | |||||
BibTeX:
@article{Michau2015199, author = {Michau, M. and Berry, A. and Micheau, Ph. and Herzog, Ph.}, title = {Optimal virtual mechanical impedances for the vibroacoustic active control of a thin plate}, journal = {Journal of the Acoustical Society of America}, year = {2015}, volume = {137}, number = {1}, pages = {199-207}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923766767&doi=10.1121%2f1.4904550&partnerID=40&md5=52311cec67cae825a8c5105d336f69e3}, doi = {https://doi.org/10.1121/1.4904550} } |
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Micheau, P., Boulandet, R., Michau, M. and Berry, A. | Active structural acoustic control of a composite panel with sensori-actuators and complex envelope controllers | 2015 | 22nd International Congress on Sound and Vibration, ICSV 2015 | conference | URL |
Abstract: In aircraft cabins, the use of composite materials leads to a reduction of the sound-insulating capability to external noise, particularly at low frequencies. Moreover, in the case of flexural structures with a high inherent structural damping like composite panels, it has been shown that adding active damping does not allow the noise transmitted to be reduced optimally. Hence, active structural acoustic control (ASAC) appears as an effective way to reduce sound radiation and transmission through panel-like structures, using secondary sources to modify the sound-radiating operating deflection shape. The objective is to design an efficient harmonic ASAC constituted of multiple secondary sources such that the actuation and sensing variables are dual and collocated. Then, each secondary source can be considered as a two-port system that directly controls the power flow to the structure, which also allows interpreting each feedback controller as a virtual mechanical impedance. The presented design considers complex envelope controllers tuned to ensure both a stable feedback system and a specific complex gain at the disturbance frequency (the required virtual mechanical impedance to reduce the sound power radiation). The new contribution of this work is to demonstrate that each complex envelope controller is equivalent to a virtual mechanical impedance, or a virtual electrical admittance from the actuator point of view. An experimental setup is presented to illustrate the method. It includes two sensori-actuators developed from two electrodynamic inertial exciters and dedicated signal processing of complex envelope. These control units are distributed over an aircraft trim panel which is subject to a time-harmonic diffuse sound field. It is shown that extra vibrational energy must be provided by the actuators for optimal sound power reduction, mainly due to the high structural damping in the aircraft composite panel. Concluding remarks and discussions on ASAC of narrowband noises for composite panels are provided. | |||||
BibTeX:
@conference{Micheau2015, author = {Micheau, P. and Boulandet, R. and Michau, M. and Berry, A.}, title = {Active structural acoustic control of a composite panel with sensori-actuators and complex envelope controllers}, journal = {22nd International Congress on Sound and Vibration, ICSV 2015}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84971299656&partnerID=40&md5=b7d2495974bba2527b6b59a4f3cb4d96} } |
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Moghadam, P., Quaegebeur, N. and Masson, P. | Mode selective generation of guided waves by systematic optimization of the interfacial shear stress profile | 2015 | Smart Materials and Structures Vol. 24(1) |
article | DOI URL |
Abstract: Piezoelectric transducers are commonly used in structural health monitoring systems to generate and measure ultrasonic guided waves (GWs) by applying interfacial shear and normal stresses to the host structure. In most cases, in order to perform damage detection, advanced signal processing techniques are required, since a minimum of two dispersive modes are propagating in the host structure. In this paper, a systematic approach for mode selection is proposed by optimizing the interfacial shear stress profile applied to the host structure, representing the first step of a global optimization of selective mode actuator design. This approach has the potential of reducing the complexity of signal processing tools as the number of propagating modes could be reduced. Using the superposition principle, an analytical method is first developed for GWs excitation by a finite number of uniform segments, each contributing with a given elementary shear stress profile. Based on this, cost functions are defined in order to minimize the undesired modes and amplify the selected mode and the optimization problem is solved with a parallel genetic algorithm optimization framework. Advantages of this method over more conventional transducers tuning approaches are that (1) the shear stress can be explicitly optimized to both excite one mode and suppress other undesired modes, (2) the size of the excitation area is not constrained and mode-selective excitation is still possible even if excitation width is smaller than all excited wavelengths, and (3) the selectivity is increased and the bandwidth extended. The complexity of the optimal shear stress profile obtained is shown considering two cost functions with various optimal excitation widths and number of segments. Results illustrate that the desired mode (A0 or S0) can be excited dominantly over other modes up to a wave power ratio of 1010 using an optimal shear stress profile. © 2015 IOP Publishing Ltd. | |||||
BibTeX:
@article{Moghadam2015, author = {Moghadam, P.Y. and Quaegebeur, N. and Masson, P.}, title = {Mode selective generation of guided waves by systematic optimization of the interfacial shear stress profile}, journal = {Smart Materials and Structures}, year = {2015}, volume = {24}, number = {1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84916208833&doi=10.1088%2f0964-1726%2f24%2f1%2f015003&partnerID=40&md5=cae26fc9aebf7d9f23f328f7f1d18296}, doi = {https://doi.org/10.1088/0964-1726/24/1/015003} } |
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Mosanenzadeh, S., Doutres, O., Naguib, H., Park, C. and Atalla, N. | A semi-empirical model relating micro structure to acoustic properties of bimodal porous material | 2015 | Journal of Applied Physics Vol. 117(3) |
article | DOI URL |
Abstract: Complex morphology of open cell porous media makes it difficult to link microstructural parameters and acoustic behavior of these materials. While morphology determines the overall sound absorption and noise damping effectiveness of a porous structure, little is known on the influence of microstructural configuration on the macroscopic properties. In the present research, a novel bimodal porous structure was designed and developed solely for modeling purposes. For the developed porous structure, it is possible to have direct control on morphological parameters and avoid complications raised by intricate pore geometries. A semi-empirical model is developed to relate microstructural parameters to macroscopic characteristics of porous material using precise characterization results based on the designed bimodal porous structures. This model specifically links macroscopic parameters including static airflow resistivity (s), thermal characteristic length (? '), viscous characteristic length (?), and dynamic tortuosity (a ) to microstructural factors such as cell wall thickness (2 t) and reticulation rate (R w). The developed model makes it possible to design the morphology of porous media to achieve optimum sound absorption performance based on the application in hand. This study makes the base for understanding the role of microstructural geometry and morphological factors on the overall macroscopic parameters of porous materials specifically for acoustic capabilities. The next step is to include other microstructural parameters as well to generalize the developed model. In the present paper, pore size was kept constant for eight categories of bimodal foams to study the effect of secondary porous structure on macroscopic properties and overall acoustic behavior of porous media. © 2015 AIP Publishing LLC. | |||||
BibTeX:
@article{Mosanenzadeh2015, author = {Mosanenzadeh, S.G. and Doutres, O. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {A semi-empirical model relating micro structure to acoustic properties of bimodal porous material}, journal = {Journal of Applied Physics}, year = {2015}, volume = {117}, number = {3}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923675434&doi=10.1063%2f1.4905834&partnerID=40&md5=4092a540ca8fe774787c51ff5e71bb83}, doi = {https://doi.org/10.1063/1.4905834} } |
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Mosanenzadeh, S., Naguib, H., Park, C. and Atalla, N. | Microstructural design of porous membrane for effective sound absorption performance | 2015 | Annual Technical Conference - ANTEC, Conference Proceedings, pp. 2826-2829 | conference | URL |
Abstract: Porous materials and foams are widely used for sound absorption purposes in different sectors. To answer the needs for light weight compact noise insulation material with high sound absorption capability, the microstructure of porous membranes can be designed for optimum performance while occupying the same volume with the same weight. Such engineered structures are known as Functionally Graded Material (FGM). In the present study, novel functionally graded foam with superior sound absorption is introduced and compared to uniform foams of the same porosity. The designed graded membrane demonstrates 20% improved performance. Foams are fabricated from bio-based polymer (Polylactide (PLA)) and are environmentally friendly. | |||||
BibTeX:
@conference{Mosanenzadeh20152826, author = {Mosanenzadeh, S.G. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {Microstructural design of porous membrane for effective sound absorption performance}, journal = {Annual Technical Conference - ANTEC, Conference Proceedings}, year = {2015}, pages = {2826-2829}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85010672527&partnerID=40&md5=722b15f15e0818051268ef70d40eb27f} } |
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Nadeau, J., Micheau, P. and Boisvert, M. | Model-Based Predictive Control Applied to a Dual Regenerative and Hydraulic Brake System | 2015 | 2015 IEEE Vehicle Power and Propulsion Conference, VPPC 2015 - Proceedings | conference | DOI URL |
Abstract: A cooperative control strategy can improve the efficiency of the dual regenerative and hydraulic brake system of an electric vehicle. Considering delays and constraints for both actuators, model- based predictive control (MPC) is an attractive approach. Its prediction capability is used to adjust the optimal input sequence according to the future system variations predicted. Therefore, this asset can improve the control performances compared to common closed loop control methods (e.g., LQR optimal control, PID). Thus, this paper proposes a simulation framework to evaluate the implementation's feasibility of a blended MPC strategy applied to a vehicle dual brake system. © 2015 IEEE. | |||||
BibTeX:
@conference{Nadeau2015, author = {Nadeau, J. and Micheau, P. and Boisvert, M.}, title = {Model-Based Predictive Control Applied to a Dual Regenerative and Hydraulic Brake System}, journal = {2015 IEEE Vehicle Power and Propulsion Conference, VPPC 2015 - Proceedings}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962800135&doi=10.1109%2fVPPC.2015.7352974&partnerID=40&md5=36544721841bfd98eeb564e933843ecf}, doi = {https://doi.org/10.1109/VPPC.2015.7352974} } |
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Nadeau, M., Sage, M., Kohlhauer, M., Robert, R., Vandamne, J., Mousseau, J., Tissier, R., Praud, J.-P., Walti, H. and Micheau, P. | Liquid ventilator for ultrafast hypothermia induction in juvenile lambs: Preliminary results | 2015 | Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS Vol. 2015-November, pp. 1695-1698 |
conference | DOI URL |
Abstract: Total liquid ventilation (TLV) is an emerging mechanical ventilation technique. In this technique, the lungs are filled with liquid perfluorocarbons (PFC) and a liquid ventilator assures ventilation by periodically renewing a volume of oxygenated, CO2 freed and temperature controlled PFC. A huge difference between conventional mechanical ventilation and TLV relates to the fact that PFCs are about 1500 times denser than air. Thus, the PFCs filled lungs turn into an efficient heat exchanger with the circulating blood. One of the most appealing utilization of the lungs as a heat exchanger in TLV is for ultrafast induction of mild therapeutic hypothermia (MTH) for neuroprotection and cardioprotection after ischemia-reperfusion injuries. This study aimed to perform ultrafast MTH induction by TLV in animals up to 25 kg, then perform a fast post-hypothermic rewarming while maintaining proper ventilation. A thermal model of the lamb and liquid ventilator was developed to predict the dynamic and the control strategy to adopt for MTH induction. Two juvenile lambs were instrumented with temperature sensors in the femoral artery, pulmonary artery, oesophagus, right eardrum and rectum. After stabilization in conventional mechanical ventilation, TLV was initiated with ultrafast MTH induction, followed by posthypothermic rewarming. Preliminary results in the two juvenile lambs reveal that the liquid ventilator Inolivent-6.0 can induce MTH by TLV in less than 2.5 min for systemic arterial blood and in less than 10 min for venous return, esophagus and eardrum. Rectal temperature reached MTH in respectively 19.4 and 17.0 min for both lambs. Experimental results were consistent with the model predictions. Moreover, blood gas analysis exhibited that the gas exchange in the lungs was maintained adequately for the entire experiments. © 2015 IEEE. | |||||
BibTeX:
@conference{Nadeau20151695, author = {Nadeau, M. and Sage, M. and Kohlhauer, M. and Robert, R. and Vandamne, J. and Mousseau, J. and Tissier, R. and Praud, J.-P. and Walti, H. and Micheau, P.}, title = {Liquid ventilator for ultrafast hypothermia induction in juvenile lambs: Preliminary results}, journal = {Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS}, year = {2015}, volume = {2015-November}, pages = {1695-1698}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84953289287&doi=10.1109%2fEMBC.2015.7318703&partnerID=40&md5=3a1211a2ad5b0a5f8962c3ec429a3efe}, doi = {https://doi.org/10.1109/EMBC.2015.7318703} } |
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Ostiguy, P.-C., Quaegebeur, N., Bilodeau, M. and Maßon, P. | Semi-analytical modelling of guided waves generation on composite structures using circular piezoceramics | 2015 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 9438 |
conference | DOI URL |
Abstract: In Structural Health Monitoring (SHM), claßical imaging techniques rely on the use of analytical formulations to predict the propagation and interaction of guided waves generated using piezoceramic (PZT) transducers. For the implementation of advanced imaging approaches on composites structures, analytical formulations need to consider (1) the dependency of phase velocity and damping as a function of angle (2) the steering effect on guided wave propagation caused by the anisotropy of the structure and (3) the full transducer dynamics. In this paper, the analytical modelling of guided waves generation by a circular PZT and propagation on composite structures is investigated. This work, based on previous work from the authors, is intended to extend a semi-analytical formulation from isotropic to transversely isotropic plate-like structures. The formulation considers the dependency of the interfacial shear streß under the PZT as a function of radius, angular frequency and orientation on the composite structure. Validation is conducted for a unidirectional transversely isotropic structure with a bonded circular PZT of 10 mm in diameter. Amplitude curves and time domain signals of the A0 and S0 modes obtained from the proposed formulation and the claßical pin-force model are first compared to Finite Element Model simulations. Experimental validation is then conducted using a 3D laser Doppler vibrometer for a non-principal direction on the composite. The results show the interest of considering a semmi-analytical formulation for which the transducer dynamics where the shear streß distribution under the transducer is considered in order to reproduce more precisely the generation of guided waves on composite structures. © 2015 SPIE. | |||||
BibTeX:
@conference{Ostiguy2015, author = {Ostiguy, P.-C. and Quaegebeur, N. and Bilodeau, M. and Maßon, P.}, title = {Semi-analytical modelling of guided waves generation on composite structures using circular piezoceramics}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2015}, volume = {9438}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84943238170&doi=10.1117%2f12.2083959&partnerID=40&md5=f9ccd687972f575ccdcdd7af19d6ff5d}, doi = {https://doi.org/10.1117/12.2083959} } |
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Ostiguy, P.-C., Quaegebeur, N. and Masson, P. | Non-destructive evaluation of coating thickness using guided waves | 2015 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 9437 |
conference | DOI URL |
Abstract: Among existing strategies for non-destructive evaluation of coating thickness, ultrasonic methods based on the measurement of the Time-of-Flight (ToF) of high frequency bulk waves propagating through the thickness of a structure are widespread. However, these methods only provide a very localized measurement of the coating thickness and the precision on the results is largely affected by the surface roughness, porosity or multi-layered nature of the host structure. Moreover, since the measurement is very local, inspection of large surfaces can be time consuming. This article presents a robust methodology for coating thickness estimation based on the generation and measurement of guided waves. Guided waves have the advantage over ultrasonic bulk waves of being less sensitive to surface roughness, and of measuring an average thickness over a wider area, thus reducing the time required to inspect large surfaces. The approach is based on an analytical multi-layer model and intercorrelation of reference and measured signals. The method is first assessed numerically for an aluminum plate, where it is demonstrated that coating thickness can be measured within a precision of 5 micrometers using the S0 mode at frequencies below 500 kHz. Then, an experimental validation is conducted and results show that coating thicknesses in the range of 10 to 200 micrometers can be estimated within a precision of 10 micrometers of the exact coating thickness on this type of structure. © 2015 SPIE. | |||||
BibTeX:
@conference{Ostiguy2015, author = {Ostiguy, P.-C. and Quaegebeur, N. and Masson, P.}, title = {Non-destructive evaluation of coating thickness using guided waves}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2015}, volume = {9437}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84943387295&doi=10.1117%2f12.2084299&partnerID=40&md5=a260fded0b39f0862b8b66db9b6343fd}, doi = {https://doi.org/10.1117/12.2084299} } |
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Ostiguy, P.-C., Quaegebeur, N. and Masson, P. | Non-destructive evaluation of coating thickness using guided waves | 2015 | NDT and E International Vol. 76, pp. 17-25 |
article | DOI URL |
Abstract: For thin coating thicknesses, techniques for thickness characterization requires a high level of precision. On composite structures, actual bulk wave methods can be impaired by the presence of a periodic metallic mesh on its surface, thus reducing their performance. In this paper, a technique based on guided waves is proposed for coating thickness characterization. This method relies on the interpolation of the linear behavior of the S |
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BibTeX:
@article{Ostiguy201517, author = {Ostiguy, P.-C. and Quaegebeur, N. and Masson, P.}, title = {Non-destructive evaluation of coating thickness using guided waves}, journal = {NDT and E International}, year = {2015}, volume = {76}, pages = {17-25}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940730830&doi=10.1016%2fj.ndteint.2015.08.004&partnerID=40&md5=dbf93235639af58d6f30c7f6bb31405a}, doi = {https://doi.org/10.1016/j.ndteint.2015.08.004} } |
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Padois, T., Sgard, F., Doutres, O. and Berry, A. | Comparison of acoustic source localization methods in time domain using sparsity constraints | 2015 | INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering | conference | URL |
Abstract: This paper deals with source localization techniques in time domain for broadband acoustic sources. The goal is to detect accurately and quickly the position and amplitude of noise sources in workplaces in order to prevent employees from hearing loss or safety risk. First, the generalized cross correlation associated with a spherical microphone array is used to get a raw noise source map. Then a linear inverse problem is defined. Commonly, linear inverse problem is solved with an l2-regularization. In this study, two sparsity constraints are used to solve the inverse problem, the orthogonal matching pursuit and the truncated Newton interior-point method. Synthetic data are used to highlight the abilities of such techniques. High resolution can be achieved for various acoustic sources configurations. Moreover, the amplitudes of the acoustic sources are correctly estimated. Finally, a comparison of computation time shows these techniques are suitable in real scenario. © 2015 by ASME. | |||||
BibTeX:
@conference{Padois2015, author = {Padois, T. and Sgard, F. and Doutres, O. and Berry, A.}, title = {Comparison of acoustic source localization methods in time domain using sparsity constraints}, journal = {INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84947579293&partnerID=40&md5=355e6c0b1070bcb9d5fa00ef717a5b00} } |
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Padois, T. and Berry, A. | Orthogonal matching pursuit applied to the deconvolution approach for the mapping of acoustic sources inverse problem | 2015 | Journal of the Acoustical Society of America Vol. 138(6), pp. 3678-3685 |
article | DOI URL |
Abstract: Microphone arrays and beamforming have become a standard method to localize aeroacoustic sources. Deconvolution techniques have been developed to improve spatial resolution of beamforming maps. The deconvolution approach for the mapping of acoustic sources (DAMAS) is a standard deconvolution technique, which has been enhanced via a sparsity approach called sparsity constrained deconvolution approach for the mapping of acoustic sources (SC-DAMAS). In this paper, the DAMAS inverse problem is solved using the orthogonal matching pursuit (OMP) and compared with beamforming and SC-DAMAS. The resulting noise source maps show that OMP-DAMAS is an efficient source localization technique in the case of uncorrelated or correlated acoustic sources. Moreover, the computation time is clearly reduced as compared to SC-DAMAS. © 2015 Acoustical Society of America. | |||||
BibTeX:
@article{Padois20153678, author = {Padois, T. and Berry, A.}, title = {Orthogonal matching pursuit applied to the deconvolution approach for the mapping of acoustic sources inverse problem}, journal = {Journal of the Acoustical Society of America}, year = {2015}, volume = {138}, number = {6}, pages = {3678-3685}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84950970979&doi=10.1121%2f1.4937609&partnerID=40&md5=1f47d0cb06335bfaa915d37308bd02b6}, doi = {https://doi.org/10.1121/1.4937609} } |
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Pouliot, G., Lacerte, M.-O., Plante, J.-S. and Micheau, P. | Design of an Eddy Current Torque Bypass Clutch for Seamless Automated Manual Transmissions of Electric and Hybrid Vehicles | 2015 | SAE International Journal of Alternative Powertrains Vol. 4(2), pp. 388-397 |
article | DOI URL |
Abstract: This paper presents the design and experimental validation of an eddy current torque transfer clutch for use inside Automated Manual Transmissions (AMTs) to perform seamless gear upshifts. Electric vehicles (EVs) with a single-ratio gearbox may provide high levels of smoothness, but using a multi-speed gearbox provides significant benefits in terms of vehicle acceleration, top speed, powertrain cost, mass, and energy consumption. AMTs can provide smooth shifts without torque interruption when coupled to a normally-open torque bypass clutch. However, conventional dry friction clutches are not best suited for such torque bypass due to wear and controllability concerns, while wet clutches would decrease powertrain efficiency due to viscous losses. An eddy current clutch would be highly controllable, simple to manufacture, low-cost, robust, and do not wear compared to friction clutches. The potential of eddy current clutches is assessed from a representative case study consisting of a 190 Nm clutch for a seamless two-speed AMT. The clutch design is based upon Wouterse's model, which is further refined using a Finite Element Analysis (FEA) on the clutch magnetic circuit. A prototype clutch is built and installed inside an existing AMT. The measured clutch coupling torque agrees well with Wouterse's model results, with a maximum error of 6%. The AMT performed seamless gear upshifts on a test bench thanks to the eddy current clutch, which confirms their viability for torque bypass. Copyright © 2015 SAE International. | |||||
BibTeX:
@article{Pouliot2015388, author = {Pouliot, G. and Lacerte, M.-O. and Plante, J.-S. and Micheau, P.}, title = {Design of an Eddy Current Torque Bypass Clutch for Seamless Automated Manual Transmissions of Electric and Hybrid Vehicles}, journal = {SAE International Journal of Alternative Powertrains}, year = {2015}, volume = {4}, number = {2}, pages = {388-397}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938563445&doi=10.4271%2f2015-01-9143&partnerID=40&md5=8a46460ae42adf5c2ee224db43522ecf}, doi = {https://doi.org/10.4271/2015-01-9143} } |
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Quaegebeur, N., Ostiguy, P.-C. and Masson, P. | Hybrid empirical/analytical modeling of guided wave generation by circular piezoceramics | 2015 | Smart Materials and Structures Vol. 24(3) |
article | DOI URL |
Abstract: Classical piezoceramic transducer design methods in structural health monitoring based on guided wave propagation rely mostly on the use of the pin-force model, assuming that a piezoelectric actuator can be modelled as a constant shear stress applied at its circumference, whatever the frequency generated. However, the assumptions of this model are only valid for thin piezoelectric elements, weak coupling between the host structure and the transducer, and when the wavelength of the generated guided wave is above the size of the transducer. In order to overcome those limitations, this paper presents an axisymmetric analysis of guided wave generation by a circular piezoceramic, considering the complex shear and normal interfacial stress profiles between the transducer and the host structure. The excitation terms are estimated empirically using a best-fit model and a function derived from measured admittance. The validity of the approach is assessed numerically and experimentally, and the influence of piezoceramic thickness on guided wave generation is accurately modeled for frequencies below the second electro-mechanical resonance frequency. © 2015 IOP Publishing Ltd. | |||||
BibTeX:
@article{Quaegebeur2015, author = {Quaegebeur, N. and Ostiguy, P.-C. and Masson, P.}, title = {Hybrid empirical/analytical modeling of guided wave generation by circular piezoceramics}, journal = {Smart Materials and Structures}, year = {2015}, volume = {24}, number = {3}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923294002&doi=10.1088%2f0964-1726%2f24%2f3%2f035003&partnerID=40&md5=f0562275ee89b054c48d22433029654e}, doi = {https://doi.org/10.1088/0964-1726/24/3/035003} } |
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Richard, S., Champoux, Y., Lépine, J. and Drouet, J.-M. | Using an alternative forced-choice method to study shock perception at cyclists' hands: The effect of tyre pressure | 2015 | Procedia Engineering Vol. 112, pp. 361-366 |
conference | DOI URL |
Abstract: In road cycling, tyre pressure has an influence on both performance and comfort of the cyclist. In this paper, the relationship between tyre pressure and shock perception at the cyclist's hands was quantitatively analysed by measuring the Just Noticeable Difference in Level (JNDL) of tyre pressure. The JNDL was determined by using a three-alternative forced-choice (3-AFC) method. The measurement was carried out on seven healthy subjects exposed to shock-type excitation on a laboratory bicycle treadmill. The dispersion of the measured tyre pressure JNDL (69 to 241 kPa; mean 155 kPa; SD 73 kPa) shows a large variability in the hands' perception of shock in the cyclists tested. This suggests that some cyclists have a better capacity than others to differentiate impact sensory inputs at the hands, making them more likely to discern subtle differences in bicycle response dynamics. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. | |||||
BibTeX:
@conference{Richard2015361, author = {Richard, S. and Champoux, Y. and Lépine, J. and Drouet, J.-M.}, title = {Using an alternative forced-choice method to study shock perception at cyclists' hands: The effect of tyre pressure}, journal = {Procedia Engineering}, year = {2015}, volume = {112}, pages = {361-366}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945570941&doi=10.1016%2fj.proeng.2015.07.263&partnerID=40&md5=d6b0c6b9402a11c91ec93a1274e402e6}, doi = {https://doi.org/10.1016/j.proeng.2015.07.263} } |
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Robin, O., Berry, A., Atalla, N., Hambric, S. and Shepherd, M. | Experimental evidence of modal wavenumber relation to zeros in the wavenumber spectrum of a simply supported plate (L) | 2015 | Journal of the Acoustical Society of America Vol. 137(5), pp. 2978-2981 |
article | DOI URL |
Abstract: The modal wavenumber of rectangular, simply supported, isotropic thin plates was theoretically shown to be related to the zeros in the wavenumber spectrum and not to the peaks, resulting in an error between the actual modal wavenumber and location of the wavenumber spectrum peak for low mode orders. This theoretical proof is confirmed by experimental results reported in this letter. © 2015 Acoustical Society of America. | |||||
BibTeX:
@article{Robin20152978, author = {Robin, O. and Berry, A. and Atalla, N. and Hambric, S.A. and Shepherd, M.R.}, title = {Experimental evidence of modal wavenumber relation to zeros in the wavenumber spectrum of a simply supported plate (L)}, journal = {Journal of the Acoustical Society of America}, year = {2015}, volume = {137}, number = {5}, pages = {2978-2981}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930226909&doi=10.1121%2f1.4919334&partnerID=40&md5=0420f8af5abbece7012dbcead5c86686}, doi = {https://doi.org/10.1121/1.4919334} } |
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Robina, O., Amedin, C., Berry, A., Atalla, N., Doutrese, O. and Sgardf, F. | Assessing sound absorption coefficient under a synthesized diffuse acoustic field: Effect of the sample size and nature | 2015 | INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering | conference | URL |
Abstract: A method for estimating the sound absorption coefficient of a material under a synthesized Diffuse Acoustic Field was recently proposed, as an alternative to classical sound absorption measurements in reverberant rooms. Using sound field reproduction approaches and a synthetic array of acoustic monopoles facing the material, estimation of the sound absorption coefficient under a reproduced Diffuse Acoustic Field but in free-field conditions was shown to be feasible. The method was successfully tested on two samples of melamine foam of close thicknesses and areas. In this paper, the principle of the method will be first recalled. The effect of varying the reproduction array size on the calculated sound absorption coefficients is then studied. A comparative measurement between the suggested method and the reverberant room method on ceiling tiles is finally reported. © 2015 by ASME. | |||||
BibTeX:
@conference{Robina2015, author = {Robina, O. and Amedin, C.K. and Berry, A. and Atalla, N. and Doutrese, O. and Sgardf, F.}, title = {Assessing sound absorption coefficient under a synthesized diffuse acoustic field: Effect of the sample size and nature}, journal = {INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84947558820&partnerID=40&md5=b87549914377bd82a6a18df864b5e53a} } |
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Sgard, F., Atalla, N. and Nélisse, H. | Prediction of the niche effect for single flat panels with or without attached sound absorbing materials | 2015 | Journal of the Acoustical Society of America Vol. 137(1), pp. 117-131 |
article | DOI URL |
Abstract: The sound transmission loss (STL) of a test sample measured in sound transmission facilities is affected by the opening in which it is located. This is called the niche effect. This paper uses a modal approach to study the STL of a rectangular plate with or without an attached porous material located inside a box-shaped niche. The porous material is modeled as a limp equivalent fluid. The proposed model is validated by comparison with finite element/boundary element computations. Using a condensation of the pressure fields in the niche, the niche effect is interpreted in terms of a modification of the modal blocked pressure fields acting on the panel induced by the front cavity and by a modification of the radiation efficiency of the panel modes due to the presence of the back cavity. The modal approach is then used to investigate the impact of (1) the presence of a porous material attached to the panel on the niche effect and (2) the niche effect on the assessment of the porous material insertion loss. A simplified model for the porous material based on a transfer matrix approach is also proposed to predict the STL of the system and its validity is discussed. © 2015 Acoustical Society of America. | |||||
BibTeX:
@article{Sgard2015117, author = {Sgard, F. and Atalla, N. and Nélisse, H.}, title = {Prediction of the niche effect for single flat panels with or without attached sound absorbing materials}, journal = {Journal of the Acoustical Society of America}, year = {2015}, volume = {137}, number = {1}, pages = {117-131}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923854096&doi=10.1121%2f1.4901713&partnerID=40&md5=b4c689b280e8b98d1230076fe730db80}, doi = {https://doi.org/10.1121/1.4901713} } |
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Temporelli, R. and Micheau, P. | Prediction of Fuel Consumption Reduction of a Recreational Vehicle by Electrification of Its Clutch Transmission | 2015 | 2015 IEEE Vehicle Power and Propulsion Conference, VPPC 2015 - Proceedings | conference | DOI URL |
Abstract: Automated Manual Transmission based on hydraulic clutch actuation gives high performances and comfort to a recreational vehicle. However, its continuous power consumption is too high to be considered in a hybrid version of a recreational vehicle. Hence, the objective is to evaluate the fuel consumption reduction achieved by the clutch electrification. The method is based on numerical models of energy consumption comparison between an actual hydraulic clutch actuator and a new electrified clutch actuator. Both simulated technologies are evaluated for preestablished clutch operational cases and a normalized driving cycle. Relative power consumption of each technology on this last cycle predicts a fuel consumption reduction of 6.2% thanks to the clutch electrification. © 2015 IEEE. | |||||
BibTeX:
@conference{Temporelli2015, author = {Temporelli, R. and Micheau, P.}, title = {Prediction of Fuel Consumption Reduction of a Recreational Vehicle by Electrification of Its Clutch Transmission}, journal = {2015 IEEE Vehicle Power and Propulsion Conference, VPPC 2015 - Proceedings}, year = {2015}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962851432&doi=10.1109%2fVPPC.2015.7352998&partnerID=40&md5=ee9126563ed8cfabafb459ae51f94b6a}, doi = {https://doi.org/10.1109/VPPC.2015.7352998} } |
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Alimonti, L., Atalla, N., Berry, A. and Sgard, F. | Erratum: Assessment of a hybrid finite element-transfer matrix model for flat structures with homogeneous acoustic treatments (Journal of the Acoustical Society of America (2014) 135 (2694-2705)) [BibTeX] |
2014 | Journal of the Acoustical Society of America Vol. 136(3), pp. 1441-1442 |
article | DOI URL |
BibTeX:
@article{Alimonti20141441, author = {Alimonti, L. and Atalla, N. and Berry, A. and Sgard, F.}, title = {Erratum: Assessment of a hybrid finite element-transfer matrix model for flat structures with homogeneous acoustic treatments (Journal of the Acoustical Society of America (2014) 135 (2694-2705))}, journal = {Journal of the Acoustical Society of America}, year = {2014}, volume = {136}, number = {3}, pages = {1441-1442}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84927125567&doi=10.1121%2f1.4892785&partnerID=40&md5=1bcc406b25d5090a1fafbc1dc7b4e3a5}, doi = {https://doi.org/10.1121/1.4892785} } |
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Alimonti, L., Atalla, N., Berry, A. and Sgard, F. | Assessment of a hybrid finite element-transfer matrix model for flat structures with homogeneous acoustic treatments | 2014 | Journal of the Acoustical Society of America Vol. 135(5), pp. 2694-2705 |
article | DOI URL |
Abstract: Modeling complex vibroacoustic systems including poroelastic materials using finite element based methods can be unfeasible for practical applications. For this reason, analytical approaches such as the transfer matrix method are often preferred to obtain a quick estimation of the vibroacoustic parameters. However, the strong assumptions inherent within the transfer matrix method lead to a lack of accuracy in the description of the geometry of the system. As a result, the transfer matrix method is inherently limited to the high frequency range. Nowadays, hybrid substructuring procedures have become quite popular. Indeed, different modeling techniques are typically sought to describe complex vibroacoustic systems over the widest possible frequency range. As a result, the flexibility and accuracy of the finite element method and the efficiency of the transfer matrix method could be coupled in a hybrid technique to obtain a reduction of the computational burden. In this work, a hybrid methodology is proposed. The performances of the method in predicting the vibroacoutic indicators of flat structures with attached homogeneous acoustic treatments are assessed. The results prove that, under certain conditions, the hybrid model allows for a reduction of the computational effort while preserving enough accuracy with respect to the full finite element solution. © 2014 Acoustical Society of America. | |||||
BibTeX:
@article{Alimonti20142694, author = {Alimonti, L. and Atalla, N. and Berry, A. and Sgard, F.}, title = {Assessment of a hybrid finite element-transfer matrix model for flat structures with homogeneous acoustic treatments}, journal = {Journal of the Acoustical Society of America}, year = {2014}, volume = {135}, number = {5}, pages = {2694-2705}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900407883&doi=10.1121%2f1.4871355&partnerID=40&md5=e47b326f3d259728616cd012751c6bfd}, doi = {https://doi.org/10.1121/1.4871355} } |
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Atalla, N. | Structural and Acoustic Noise Control Material Modeling | 2014 | Engineering Vibroacoustic Analysis: Methods and Applications, pp. 230-267 | book | DOI URL |
Abstract: Proper selection of noise control materials is an important consideration for the noise control engineer. Damping treatments are most effective in reducing structureborne noise at resonances. The classical passive dampers are viscoelastic materials. This chapter provides an overview of the methods used to model and characterize sound packages with an emphasis on viscoelastic and poroelastic materials. The presentation is focused on simple engineering methods. The detailed vibroacoustic response of structures with attached noise control material (multilayer made up from foams, fibers, felts, resistive screens, air gaps) is classically modeled using the finite element and the boundary element methods. While accurate and mature, such methods still require cumbersome calculations for large models and/or extended spectral analyses. An alternative to these full numerical methods, valid and sufficient for numerous engineering applications, is based on the transfer matrix method. © 2016 John Wiley & Sons, Ltd. All rights reserved. | |||||
BibTeX:
@book{Atalla2014230, author = {Atalla, N.}, title = {Structural and Acoustic Noise Control Material Modeling}, journal = {Engineering Vibroacoustic Analysis: Methods and Applications}, year = {2014}, pages = {230-267}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84986253815&doi=10.1002%2f9781118693988.ch8&partnerID=40&md5=89d85d1fcd70053390b155657187906c}, doi = {https://doi.org/10.1002/9781118693988.ch8} } |
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Atalla, N. | Modeling the sound transmission through complex structures with attached noise control materials | 2014 | Wave Motion Vol. 51(4), pp. 650-663 |
article | DOI URL |
Abstract: This paper discusses three extensions of the Transfer Matrix Method (TMM). The first deals with the modeling of the transmission loss of sandwich-composite panels. A wave based model is recalled and used to derive a simpler model based on identifying effective properties of an equivalent orthotropic panel. An experimental case study is presented to show the accuracy of these models when used to predict practical sound transmission problems involving single wall sandwich-honeycomb panels and double wall sandwich-honeycomb with an absorbing material filling the cavity between the two panels. In the second extension, the use of the TMM to predict the response of panels under various types of excitations is discussed. A wave based method is presented and compared with Finite Element Method (FEM) predictions for two types of excitations: Turbulent Boundary Layer (TBL) and point source. The comparison shows that the method allows for accurate predictions of the frequency averaged Transmission Loss (TL). Finally, the use of the TMM to model double wall systems with mechanical links is presented and numerically validated using FEM. It is found that the method captures well the decrease of the TL due to the insertion of the links and the effect of the excitation nature on this decrease. © 2013 Elsevier B.V. | |||||
BibTeX:
@article{Atalla2014650, author = {Atalla, N.}, title = {Modeling the sound transmission through complex structures with attached noise control materials}, journal = {Wave Motion}, year = {2014}, volume = {51}, number = {4}, pages = {650-663}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84898003842&doi=10.1016%2fj.wavemoti.2013.11.001&partnerID=40&md5=202a4bf24da2f17f56760e2c5ab60e98}, doi = {https://doi.org/10.1016/j.wavemoti.2013.11.001} } |
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Berry, A., Robin, O. and Pierron, F. | Identification of dynamic loading on a bending plate using the Virtual Fields Method | 2014 | Journal of Sound and Vibration Vol. 333(26), pp. 7151-7164 |
article | DOI URL |
Abstract: This paper aims at identifying local dynamic transverse forces and distributed pressures acting on the surface of a thin plate, from its measured vibration response. It is related to previous work by other authors on the so-called Force Analysis Technique but uses a different formulation. The paper first presents the theoretical developments based on the Virtual Fields Method and then, numerically simulated data are processed to validate the identification algorithm. Finally, experimental data are used. Both mechanical point load excitation, and distributed acoustic excitation of a bending panel are considered. The force reconstruction results are very satisfactory and the low computational times together with the simple implementation make the Virtual Fields technique attractive for this type of problem. © 2014 Elsevier Ltd. | |||||
BibTeX:
@article{Berry20147151, author = {Berry, A. and Robin, O. and Pierron, F.}, title = {Identification of dynamic loading on a bending plate using the Virtual Fields Method}, journal = {Journal of Sound and Vibration}, year = {2014}, volume = {333}, number = {26}, pages = {7151-7164}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907646424&doi=10.1016%2fj.jsv.2014.08.038&partnerID=40&md5=ba6350de8ccab5c40155c58ad1354c72}, doi = {https://doi.org/10.1016/j.jsv.2014.08.038} } |
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Bolduc, A., Gauthier, P.-A., Ramanana, T. and Berry, A. | Sound Field Reproduction of vibroacoustic models: Application to a plate with Wave Field Synthesis | 2014 | Proceedings of the AES International Conference Vol. 2014-January |
conference | URL |
Abstract: In an engineering context, objective evaluation of vibroacoustic models is traditionally performed with visual or numeric information. However, actual auditory perception cannot be transmitted through these types of objective representations. Sound Field Reproduction (SFR) of sound fields emitted by physical objects is often based on simplistic point source models with modified radiation properties or from recordings, using stereophonic or binaural techniques. In the perspective of better perceptual evaluation of engineered products, it would be useful if such methods would not be limited to certain types of sources, modeling techniques or predefined listening spots. A general SFR method using Wave Field Synthesis formalism applied to common vibroacoustic models as found in mechanical engineering is proposed. SFR applied to an analytical model of a harmonic or broadband excited plate is studied using three Secondary source distributions geometries. Results of numerical simulations illustrate the viability and limits of the approach. Copyright © Audio Engineering Society 2014. | |||||
BibTeX:
@conference{Bolduc2014, author = {Bolduc, A. and Gauthier, P.-A. and Ramanana, T. and Berry, A.}, title = {Sound Field Reproduction of vibroacoustic models: Application to a plate with Wave Field Synthesis}, journal = {Proceedings of the AES International Conference}, year = {2014}, volume = {2014-January}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938866968&partnerID=40&md5=0b3bc0ee90f367bce8cda44e305d8006} } |
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Boulandet, R., Pelletier, A., Micheau, P. and Berry, A. | Active vibration control using self-sensing actuators: An experimental comparison of piezoelectric and electromagnetic technologies | 2014 | ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) Vol. 13 |
conference | DOI URL |
Abstract: The paper addresses the practical implementation of active vibration control using self-sensing actuators, intending to equip smart structures. The control objective is to reduce the structural vibration of a simply-supported plate subject to time-harmonic excitation. The key challenge is to use a self-sensing actuator instead of a sensor-actuator pair to reject the primary disturbance at the control point. In this study, two types of self-sensing actuators designed from a PZT patch and an electrodynamic inertial exciter are discussed, and their overall performance is compared in terms of reduction of flexural energy and power consumption. Both technologies have proven to be efficient in achieving a time-harmonic vibration control and may be used alternately, depending on the application at hand. Copyright © 2014 by ASME. | |||||
BibTeX:
@conference{Boulandet2014, author = {Boulandet, R. and Pelletier, A. and Micheau, P. and Berry, A.}, title = {Active vibration control using self-sensing actuators: An experimental comparison of piezoelectric and electromagnetic technologies}, journal = {ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)}, year = {2014}, volume = {13}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926355231&doi=10.1115%2fIMECE2014-40082&partnerID=40&md5=95e19205bf9c398b388a1273edf0e984}, doi = {https://doi.org/10.1115/IMECE2014-40082} } |
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Boulandet, R., Michau, M., Micheau, P. and Berry, A. | Active reduction of sound transmission in aircraft cabins: A smarter use of vibration exciters | 2014 | INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control | conference | URL |
Abstract: This paper addresses an active structural acoustic control (ASAC) approach to reduce sound transmission through an aircraft trim panel. The focus is on the practical implementation of the virtual mechanical impedance approach through self-sensing actuation instead of using sensor-actuator pairs. The experimental setup includes two sensoriactuators designed from an electrodynamic inertial exciter and distributed over an aircraft trim panel, which is subject to a time-harmonic diffuse sound field. A methodology based on the experimental identification of key parameters of the actuator is proposed, wherein the vibration of the structure is estimated from the electrical signals picked up at the input terminals of the transducer. Measured data are compared to results obtained with conventional sensor-actuator pairs consisting of an accelerometer and an inertial exciter, particularly as regards sound power reduction. The decrease of sound power radiated is comparable in both cases and equals 3 dB when the panel is controlled at the excitation frequency of 363 Hz, as expected by optimal calculation for two control units. | |||||
BibTeX:
@conference{Boulandet2014, author = {Boulandet, R. and Michau, M. and Micheau, P. and Berry, A.}, title = {Active reduction of sound transmission in aircraft cabins: A smarter use of vibration exciters}, journal = {INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control}, year = {2014}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923615653&partnerID=40&md5=f7dd543dc8a1aef361cc79f9d277d5a6} } |
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Cardina, M. and Masson, P. | Fully-coupled 6 DoF model for unmanned version of the SA160 general aviation aircraft | 2014 | AIAA Atmospheric Flight Mechanics Conference | conference | DOI URL |
Abstract: With the growing use of Unmanned Aerial Vehicle (UAV) in civilian airspace, design and development of this type of aircraft requires a thorough study of its dynamics in order to demonstrate airworthiness of such a system. This paper describes the first step in the development of an unmanned version of the SA160 aircraft by presenting a fully-coupled 6 DoF model of the SA160 aircraft. As the aerodynamic parameters are evaluated with inflight data using the SIDPAC (System Identification Program for AirCraft) software, the problem addressed in this paper is the validation of a predictive model for the dynamic response of the SA160 based on identified parameters. In this work, a state-space representation is used for the dynamic modeling of the SA160 single-engine aircraft. The a priori unknown aerodynamic coefficients are first estimated using a Digital Datcom (U.S. Air Force Digital Data Compendium) model. These coefficients are used as initial estimates for the output-error method. The effect of the rotating propeller on the aircraft dynamics is included in order to account for aerodynamic and inertial coupling. The dynamic model is based on the small-disturbance theory, so that aircraft motion is simulated around equilibrium flight conditions. Furthermore, the dynamic model elaborated in this paper is based on dimensionless linearized equations. The main goal is to demonstrate that the state-space model parameters identified through flight test program provide reliable and accurate dynamic model. System identification techniques are then used with in-flight data from an instrumented aircraft. Instrumentation includes an air data boom and an inertial measurement unit fitted to the SA160 in order to get a full set of in-flight aerodynamic and 6 DoF dynamic data. The flight control surfaces deflection is also measured with linear position measurements sensors. The inputs applied to flight control surfaces (elevator, ailerons and rudder) are designed such as to excite the aircraft in order to provide sufficiently rich data quality for modeling. Results from the model with identified SA160 aerodynamic parameters are compared to flight test data. Different sets of longitudinal, lateral/directional and fully-coupled maneuvers are performed for specific flight conditions. In the system identification process, aerodynamic parameters identified from longitudinal and lateral/directional dynamics are used as inputs for the output-error method applied for the fully-coupled case, and the amount of aerodynamic coupling is addressed. | |||||
BibTeX:
@conference{Cardina2014, author = {Cardina, M. and Masson, P.}, title = {Fully-coupled 6 DoF model for unmanned version of the SA160 general aviation aircraft}, journal = {AIAA Atmospheric Flight Mechanics Conference}, year = {2014}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894425005&doi=10.2514%2f6.2014-0382&partnerID=40&md5=5b4546bb7676f868667055c59ffc19db}, doi = {https://doi.org/10.2514/6.2014-0382} } |
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Doutres, O., Atalla, N. and Osman, H. | Modeling and experimental validation of cellular porous material with large resonant inclusions | 2014 | INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control | conference | URL |
Abstract: Porousmaterials are widely used for improving sound absorption and sound transmission loss of vibrating structures. However, their efficiency is limited to medium and high frequencies. A common solution for improving their low frequency behavior while keeping an acceptable thickness is to embed resonant structures such as Helmholtz resonators. This work investigates the absorption and transmission acoustic performances of a cellular porous material with large resonatorinclusions. The homogenization theory cannot be appliedto cellular material made of suchlargeperiodic unit-cell (e.g., cubeof side L˜100 mm). A low frequency modelof a larger esonant unit-cell based on the Parallel Transfer Matrix Methodis proposedin this work.Theproposed model is validated by comparison with impedance tube measurements and finite element calculations. At the Helmholtzresonance frequency; (i) the transmission loss is greatly improved and (ii) the sound absorption of the host material isdecreasedif it is made of a highly sound absorbing material. | |||||
BibTeX:
@conference{Doutres2014, author = {Doutres, O. and Atalla, N. and Osman, H.}, title = {Modeling and experimental validation of cellular porous material with large resonant inclusions}, journal = {INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control}, year = {2014}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923593244&partnerID=40&md5=8cf571a9f4ea318d82c9c578279cd91e} } |
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Doutres, O., Atalla, N., Brouillette, M. and Hébert, C. | Using shock waves to improve the sound absorbing efficiency of closed-cell foams | 2014 | Applied Acoustics Vol. 79, pp. 110-116 |
article | DOI URL |
Abstract: Producing closed-cell foams is generally cheaper and simpler than open-cell foams. However, the acoustic and filtration efficiency of closed-cell foam materials is generally poor because it is very difficult for fluid or acoustic waves to penetrate into the material. A new method using shock waves to remove the membranes closing the cell pores (known as reticulation) and thus to improve the acoustic and filtration behavior of closed-cell foam material is presented. Various shock treatments have been carried out on polyurethane and polyimide foams and the following conclusions were drawn: (1) reticulation efficiency increased and thus the airflow resistivity and tortuosity decreased when increasing the amplitude of the shock treatment; (2) the rigidity of the foam is decreased; (3) the process is reliable and repeatable and (4) obtained acoustic performance is comparable to classical thermal reticulation. © 2013 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Doutres2014110, author = {Doutres, O. and Atalla, N. and Brouillette, M. and Hébert, C.}, title = {Using shock waves to improve the sound absorbing efficiency of closed-cell foams}, journal = {Applied Acoustics}, year = {2014}, volume = {79}, pages = {110-116}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892576895&doi=10.1016%2fj.apacoust.2013.12.022&partnerID=40&md5=70fab72186217662226d05adc7b77622}, doi = {https://doi.org/10.1016/j.apacoust.2013.12.022} } |
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Doutres, O., Ouisse, M., Atalla, N. and Ichchou, M. | Impact of the irregular microgeometry of polyurethane foam on the macroscopic acoustic behavior predicted by a unit-cell model | 2014 | Journal of the Acoustical Society of America Vol. 136(4), pp. 1666-1681 |
article | DOI URL |
Abstract: This paper deals with the prediction of the macroscopic sound absorption behavior of highly porous polyurethane foams using two unit-cell microstructure-based models recently developed by Doutres, Atalla, and Dong [J. Appl. Phys. 110, 064901 (2011); J. Appl. Phys. 113, 054901 (2013)]. In these models, the porous material is idealized as a packing of a tetrakaidecahedra unit-cell representative of the disordered network that constitutes the porous frame. The non-acoustic parameters involved in the classical Johnson-Champoux-Allard model (i.e., porosity, airflow resistivity, tortuosity, etc.) are derived from characteristic properties of the unit-cell and semi-empirical relationships. A global sensitivity analysis is performed on these two models in order to investigate how the variability associated with the measured unit-cell characteristics affects the models outputs. This allows identification of the possible limitations of a unit-cell micro-macro approach due to microstructure irregularity. The sensitivity analysis mainly shows that for moderately and highly reticulated polyurethane foams, the strut length parameter is the key parameter since it greatly impacts three important non-acoustic parameters and causes large uncertainty on the sound absorption coefficient even if its measurement variability is moderate. For foams with a slight inhomogeneity and anisotropy, a micro-macro model associated to cell size measurements should be preferred. © 2014 Acoustical Society of America. | |||||
BibTeX:
@article{Doutres20141666, author = {Doutres, O. and Ouisse, M. and Atalla, N. and Ichchou, M.}, title = {Impact of the irregular microgeometry of polyurethane foam on the macroscopic acoustic behavior predicted by a unit-cell model}, journal = {Journal of the Acoustical Society of America}, year = {2014}, volume = {136}, number = {4}, pages = {1666-1681}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907882571&doi=10.1121%2f1.4895695&partnerID=40&md5=81676829c8e2a08b185cf8bb28d2f0f2}, doi = {https://doi.org/10.1121/1.4895695} } |
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Drouet, J.-M. and Champoux, Y. | Designing a strain gauge transducer for dynamic load measurement in cycling using numerical simulation | 2014 | Procedia Engineering Vol. 72, pp. 304-309 |
conference | DOI URL |
Abstract: The aim of this work is to study the effect of a beam transducer's modal behaviour, suspended mass and system damping on the load measurement accuracy using base excitation, and to provide insight to engineers on the process of designing a strain gauge beam transducer to measure dynamic loads. Development and results for a simple beam transducer and an instrumented brake hood and seat post are presented. One of the main conclusions to be drawn from the results presented is that, in the case of base excitation, the transducer's first bending mode has no negative effect on the measurement accuracy. © 2014 The Authors. | |||||
BibTeX:
@conference{Drouet2014304, author = {Drouet, J.-M. and Champoux, Y.}, title = {Designing a strain gauge transducer for dynamic load measurement in cycling using numerical simulation}, journal = {Procedia Engineering}, year = {2014}, volume = {72}, pages = {304-309}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903769794&doi=10.1016%2fj.proeng.2014.06.016&partnerID=40&md5=624183d924624bd8ec439dc031e866a7}, doi = {https://doi.org/10.1016/j.proeng.2014.06.016} } |
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Gauthier, P.-A., Padois, T., Ramanana, T., Bolduc, A., Pasco, Y. and Berry, A. | Sound field capture with microphone arrays, proximity microphones, and optimal filters | 2014 | Proceedings of the AES International Conference Vol. 2014-January |
conference | URL |
Abstract: The aim of sound field reproduction is to physically reproduce a sound field in an extended area using loudspeaker arrays. Typically, the virtual scene is described by a composition of simple sources (spherical waves, plane waves) fed by monophonic signals from proximity microphones or a microphone array recording. It would be useful to combine these approaches in order to separate monophonic signals to drive simple foreground virtual sources from the remaining immersing sound environment. In this paper, the combination of proximity microphones and microphone arrays is investigated in order to separate the sound source signals with proximity microphones from the remaining sound environment. Optimal (Wiener) filters are used for this purpose. Results of numerical simulations and acoustic imaging illustrate the viability of the approach. Copyright © Audio Engineering Society 2014. | |||||
BibTeX:
@conference{Gauthier2014, author = {Gauthier, P.-A. and Padois, T. and Ramanana, T. and Bolduc, A. and Pasco, Y. and Berry, A.}, title = {Sound field capture with microphone arrays, proximity microphones, and optimal filters}, journal = {Proceedings of the AES International Conference}, year = {2014}, volume = {2014-January}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938863146&partnerID=40&md5=d633ed3e39b4f3d9e418f0072665961e} } |
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Gauthier, P.-A., Chambatte, É., Camier, C., Pasco, Y. and Berry, A. | Beamforming regularization, scaling matrices, and inverse problems for sound field extrapolation and characterization: Part II* - Experiments | 2014 | AES: Journal of the Audio Engineering Society Vol. 62(4), pp. 207-219 |
article | DOI URL |
Abstract: Sound field extrapolation (SFE) is aimed at the prediction of a sound field in an extrapolation region using a microphone array. For sound environment reproduction purposes, sound field characterization (SFC) aims at a more generic or parametric description of a measured or extrapolated sound field using different physical or subjective metrics. In this paper experiments with a recently-developed SFE method (Part I - Theory) are reported in a first instance. The method is based on an inverse problem formulation combined with a recently proposed regularization approach: a delay-and-sum beamforming matrix in the discrete smoothing norm of the cost function. In a second instance, the results obtained from the SFE method are applied to SFC as presented in Part I. The SFC classification method is verified in two environments that recreate ideal or complex sound fields. In light of the presented results and discussion it is argued that the SFE and SFC proposed methods are effective. | |||||
BibTeX:
@article{Gauthier2014207, author = {Gauthier, P.-A. and Chambatte, É. and Camier, C. and Pasco, Y. and Berry, A.}, title = {Beamforming regularization, scaling matrices, and inverse problems for sound field extrapolation and characterization: Part II* - Experiments}, journal = {AES: Journal of the Audio Engineering Society}, year = {2014}, volume = {62}, number = {4}, pages = {207-219}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84899078988&doi=10.17743%2fjaes.2014.0017&partnerID=40&md5=bb9af8209b117aef63a692dbf934af71}, doi = {https://doi.org/10.17743/jaes.2014.0017} } |
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Gauthier, P.-A., Gérard, A., Camier, C. and Berry, A. | Acoustical inverse problems regularization: Direct definition of filter factors using signal-to-noise ratio | 2014 | Journal of Sound and Vibration Vol. 333(3), pp. 761-773 |
article | DOI URL |
Abstract: Acoustic imaging aims at localization and characterization of sound sources using microphone arrays. In this paper a new regularization method for acoustic imaging by inverse approach is proposed. The method first relies on the singular value decomposition of the plant matrix and on the projection of the measured data on the corresponding singular vectors. In place of regularization using classical methods such as truncated singular value decomposition and Tikhonov regularization, the proposed method involves the direct definition of the filter factors on the basis of a thresholding operation, defined from the estimated measurement noise. The thresholding operation is achieved using modified filter functions. The originality of the approach is to propose the definition of a filter factor which provides more damping to the singular components dominated by noise than that given by the Tikhonov filter. This has the advantage of potentially simplifying the selection of the best regularization amount in inverse problems. Theoretical results show that this method is comparatively more accurate than Tikhonov regularization and truncated singular value decomposition. © 2013 Elsevier Ltd. | |||||
BibTeX:
@article{Gauthier2014761, author = {Gauthier, P.-A. and Gérard, A. and Camier, C. and Berry, A.}, title = {Acoustical inverse problems regularization: Direct definition of filter factors using signal-to-noise ratio}, journal = {Journal of Sound and Vibration}, year = {2014}, volume = {333}, number = {3}, pages = {761-773}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84888307185&doi=10.1016%2fj.jsv.2013.10.011&partnerID=40&md5=a3c44e5e7564d704ca24feef0489c072}, doi = {https://doi.org/10.1016/j.jsv.2013.10.011} } |
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Gauthier, P.-A., Chambatte, E., Camier, C., Pasco, Y. and Berry, A. | Beamforming regularization, scaling matrices, and inverse problems for sound field extrapolation and characterization: Part I -theory | 2014 | AES: Journal of the Audio Engineering Society Vol. 62(3), pp. 77-98 |
article | DOI URL |
Abstract: Sound field extrapolation (SFE) is aimed at the prediction of a sound field in an extrapolation region using a microphone array in a measurement region. For sound environment reproduction purposes, sound field characterization (SFC) aims at a more generic or parametric description of a measured or extrapolated sound field using different physical or subjective metrics. In this paper an SFE method recently introduced is presented and further developed. The method is based on an inverse problem formulation combined with a beamforming matrix in the discrete smoothing norm of the cost function. The results obtained from the SFE method are applied to SFC. A set of classification criteria is proposed to distinguish simple types of sound fields on the basis of simple scalar metrics. A companion paper presents the experimental verifications of the theory presented in this paper. | |||||
BibTeX:
@article{Gauthier201477, author = {Gauthier, P.-A. and Chambatte, E. and Camier, C. and Pasco, Y. and Berry, A.}, title = {Beamforming regularization, scaling matrices, and inverse problems for sound field extrapolation and characterization: Part I -theory}, journal = {AES: Journal of the Audio Engineering Society}, year = {2014}, volume = {62}, number = {3}, pages = {77-98}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897014699&doi=10.17743%2fjaes.2014.0007&partnerID=40&md5=0401e406955da24b07abf31d32ba2f0b}, doi = {https://doi.org/10.17743/jaes.2014.0007} } |
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Ghaffari Mosanenzadeh, S., Naguib, H., Park, C. and Atalla, N. | Effect of biopolymer blends on physical and Acoustical properties of biocomposite foams | 2014 | Journal of Polymer Science, Part B: Polymer Physics Vol. 52(15), pp. 1002-1013 |
article | DOI URL |
Abstract: Bio-based foams are the solution to environmental concerns raised by petrochemical-based open cell foams used in various industries for sound absorption. While conventional petrochemical-based polymers take centuries to degrade or may not degrade at all, bio-based polymers decompose to biomass, water, and carbon dioxide in a matter of months when exposed to proper environment. To increase the potential of replacing current petrochemical foams, mechanical as well as acoustic characteristics of bio-based foams need to be improved. This article studies the effect of blending two bio-based polymers and physics of the blends on acoustic and mechanical properties of resulting polymer composite foams. Different blends of polylactide with three grades of polyhydroxyalkanoates were foamed and characterized based on acoustic and mechanical performance. Rheological properties of pure polymers as well as their blends were studied and effect of polymer blends on acoustic absorption of the resulting foams was investigated. © 2014 Wiley Periodicals, Inc. | |||||
BibTeX:
@article{GhaffariMosanenzadeh20141002, author = {Ghaffari Mosanenzadeh, S. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {Effect of biopolymer blends on physical and Acoustical properties of biocomposite foams}, journal = {Journal of Polymer Science, Part B: Polymer Physics}, year = {2014}, volume = {52}, number = {15}, pages = {1002-1013}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903307343&doi=10.1002%2fpolb.23522&partnerID=40&md5=244e4a4b9eb1aee3f7bf5cd09e6f0aee}, doi = {https://doi.org/10.1002/polb.23522} } |
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Le Duff, A., Quaegebeur, N., Ostiguy, P.-C. and Masson, P. | Precision of imaging algorithms based on ToF estimation of guided waves | 2014 | 7th European Workshop on Structural Health Monitoring, EWSHM 2014 - 2nd European Conference of the Prognostics and Health Management (PHM) Society, pp. 615-622 | conference | URL |
Abstract: This article addresses the problem of damage localization in an isotropic plate using guided waves. This localization is based on Time of Flight measurements thanks to an array of three sensors arbitrarily distributed on the structure. First, an exact solution of the Time of Flight problem is proposed. Then, the exact analytical Cramer-Rao Bounds, expressed as a function of the actuator and the sensors locations and the Signal to Noise Ratio of the measured signals, are presented. Statistical performance of the method is illustrated by means of Monte-Carlo simulations and compared to the Cramer-Rao Bounds. Time delays are estimated both with an Hilbert Transform method and a Maximum Likelihood Estimator. Results show that the performance of the algorithms is in agreement with the theoretical variance if Signal to Noise Ratio is low enough. These Cramer-Rao Bounds provide a way to determine the optimal position of a sensor array for a given a-priori accuracy. Copyright © Inria (2014). | |||||
BibTeX:
@conference{LeDuff2014615, author = {Le Duff, A. and Quaegebeur, N. and Ostiguy, P.-C. and Masson, P.}, title = {Precision of imaging algorithms based on ToF estimation of guided waves}, journal = {7th European Workshop on Structural Health Monitoring, EWSHM 2014 - 2nd European Conference of the Prognostics and Health Management (PHM) Society}, year = {2014}, pages = {615-622}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939452379&partnerID=40&md5=023ddc01169aaab0a49faced070771d0} } |
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Lépine, J., Champoux, Y. and Drouet, J.-M. | Road bike comfort: On the measurement of vibrations induced to cyclist | 2014 | Sports Engineering Vol. 17(2), pp. 113-122 |
article | DOI URL |
Abstract: With ride quality being one of the most sought-after characteristics of a road bicycle by customers as well as by bicycle manufacturers, the vibrational behaviour of the bicycle/cyclist system has grown into an active field in sport engineering research in recent years. When assessing bicycle transmissibility and ride comfort, it is important to control test conditions to obtain repeatable load and acceleration measurements at the cyclist's contact points with the bicycle. Surprisingly, however, this consideration has not yet been specifically addressed in the literature. The aim of this paper is a first effort to investigate the effect of a selected set of test conditions on the measurement of vibration induced to the cyclist by a road bicycle. Our results showed that all the test conditions selected had a significant effect on the level of vibration induced to the cyclist. © 2013 International Sports Engineering Association. | |||||
BibTeX:
@article{Lépine2014113, author = {Lépine, J. and Champoux, Y. and Drouet, J.-M.}, title = {Road bike comfort: On the measurement of vibrations induced to cyclist}, journal = {Sports Engineering}, year = {2014}, volume = {17}, number = {2}, pages = {113-122}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900509691&doi=10.1007%2fs12283-013-0145-8&partnerID=40&md5=768d65dd6c6ee0e72d60be16fa86b84e}, doi = {https://doi.org/10.1007/s12283-013-0145-8} } |
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Magne, S., Sanjosé, M., Moreau, S. and Berry, A. | Numerical optimization of fan tonal noise control using acoustic modulation of slowly-rotating obstructions | 2014 | 20th AIAA/CEAS Aeroacoustics Conference | conference | URL |
Abstract: A carefully-shaped, static obstruction placed at the inlet of a low-speed fan is a cheap, yet effective way to reduce the tonal noise. In the optimization process, the acoustic modulation introduced by a slow rotation of the obstruction allows separating the obstruction secondary contribution from the fan primary noise. As an attempt to numerically estimate the optimal obstruction design, Lattice-Boltzmann simulations of an axial ring fan were compared with measurements in a fully anechoic chamber. Numerical results without an obstruction showed an excellent prediction of the fan performance and the far-field acoustic signature (broadband and tonal noise). With a slowly-rotating obstruction, the experimental and numerical results predicted the exact same optimal lobe amplitude, which demonstrates the feasibility to numerically optimize the obstruction design. | |||||
BibTeX:
@conference{Magne2014, author = {Magne, S. and Sanjosé, M. and Moreau, S. and Berry, A.}, title = {Numerical optimization of fan tonal noise control using acoustic modulation of slowly-rotating obstructions}, journal = {20th AIAA/CEAS Aeroacoustics Conference}, year = {2014}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903907756&partnerID=40&md5=9210b5847c8e93d16022b9db7443bd7c} } |
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Michau, M., Berry, A., Micheau, P. and Herzog, P. | Optimal virtual mechanical impedances approach for the vibroacoustic active control of a panel | 2014 | 21st International Congress on Sound and Vibration 2014, ICSV 2014 Vol. 2, pp. 1565-1572 |
conference | URL |
Abstract: In order to reduce the acoustic power radiated by a structure, co-located actuator and sensor pairs are used to virtually implement local mechanical impedance. For each pair, at each frequency of interest, the virtual mechanical impedance is a complex value which imposes a linear relationship between the dual local variables of the actuator input and the sensor output. The optimal virtual mechanical impedances are defined at each frequency as the ones which minimize the sound power radiated by the structure. From a theoretical point of view, they can be computed from the primary sound field and the transfer functions between the control actuators, structural sensors and far-field acoustic sensors. The proposed experimental approach is a two-step process: (1) measurement and identification of transfer functions to compute the optimal virtual mechanical impedances; (2) implementation of the computed virtual mechanical impedances with a real-time MIMO harmonic controller. Measured and computed results are presented for a simply supported thin plate (aluminum). Special focus is put on the discussion about such control approach versus a classical active damping where the virtual mechanical impedance is defined as real positive. | |||||
BibTeX:
@conference{Michau20141565, author = {Michau, M. and Berry, A. and Micheau, P. and Herzog, P.}, title = {Optimal virtual mechanical impedances approach for the vibroacoustic active control of a panel}, journal = {21st International Congress on Sound and Vibration 2014, ICSV 2014}, year = {2014}, volume = {2}, pages = {1565-1572}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84922597345&partnerID=40&md5=c6e5b2827e14c763a3b2b57aeebb340f} } |
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Michau, M., Micheau, P., Boulandet, R., Berry, A. and Herzog, P. | Decentralized complex envelope controller for ASAC by virtual mechanical impedances | 2014 | IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM, pp. 162-167 | conference | DOI URL |
Abstract: The problem of Active Structural Acoustic Control (ASAC) is to attenuate the radiated sound power by energy injection using structural actuators to modify deflection shapes. Collocated and dual actuator-sensor pairs allow the feedback problem to be formulated as the implementation of virtual mechanical impedances. The approach is based on a two-step process: (1) the virtual impedance is derived from measurements of the primary sound and transfer functions; (2) the centralized or decentralized complex envelope controller is designed to ensure stable feedback loops. Experiments are performed on a curved composite aircraft panel comprising a window. The proposed approach leads to the implementation of active virtual impedances and unstable compensators. An increased kinetic energy of the panel is observed, thus demonstrating that the control inputs needs to provide vibrational energy to achieve sound power reduction (2.7dB). © 2014 IEEE. | |||||
BibTeX:
@conference{Michau2014162, author = {Michau, M. and Micheau, Ph. and Boulandet, R. and Berry, A. and Herzog, Ph.}, title = {Decentralized complex envelope controller for ASAC by virtual mechanical impedances}, journal = {IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM}, year = {2014}, pages = {162-167}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84906673231&doi=10.1109%2fAIM.2014.6878072&partnerID=40&md5=cab0a576d44f3c368fc4838b38ba5129}, doi = {https://doi.org/10.1109/AIM.2014.6878072} } |
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Michau, M., Berry, A., Herzog, P. and Micheau, P. | Bending nearfield compensation in the context of vibroacoustic active control | 2014 | Mechanics and Industry Vol. 15(6), pp. 551-555 |
article | DOI URL |
Abstract: The efficiency of passive methods for noise reduction decreases at low frequency. In this frequency range active structural acoustic control (ASAC) can reduce sound radiation of structures by controlling their vibration usually using piezoelectric or electrodynamic transducers. Besides its global effect on the structure, a bending nearfield is observed, depending on the actuator type. In some ASAC strategies as in the virtual impedance approach, actuators and sensors are collocated. Although it does not affect the radiation of the structure, the local bending strongly modifies the transfer function between transducers. A method is proposed in order to identify and compensate it. The global part of the vibratory field is extracted by cancelling the contribution of higher order modes approximated as a stiffness. After compensation, the signal from the sensor is much more representative of the radiation and nearly independent of the nature and the size of the actuator. © 2014 AFM, EDP Sciences. | |||||
BibTeX:
@article{Michau2014551, author = {Michau, M. and Berry, A. and Herzog, P. and Micheau, P.}, title = {Bending nearfield compensation in the context of vibroacoustic active control}, journal = {Mechanics and Industry}, year = {2014}, volume = {15}, number = {6}, pages = {551-555}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84916930945&doi=10.1051%2fmeca%2f2014078&partnerID=40&md5=2b8848ffc7035a0c43381453d8683c85}, doi = {https://doi.org/10.1051/meca/2014078} } |
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Mosanenzadeh, S., Naguib, H., Park, C. and Atalla, N. | Development of polylactide open-cell foams with bimodal structure for high-acoustic absorption | 2014 | Journal of Applied Polymer Science Vol. 131(7) |
article | DOI URL |
Abstract: In this study, a highly porous and interconnected foam structure was fabricated using compression molding combined with particulate-leaching technique. The foamed structures were fabricated with polylactide (PLA) and polyethylene glycol (PEG) with salt as the particulate. The pore size of the foam structure is controlled by the particulates size and higher interconnectivity is achieved by the co-continuous blending morphology of the PLA matrix with the water-soluble PEG. PLA is a fully bio-based thermoplastic polymer and is derived from renewable resources, such as cornstarch or sugarcanes. PEG is also fully biodegradable polymer produced from ethylene. Fabricated foams were characterized for cellular, acoustic, and mechanical properties. The acoustic performance of the foams was studied by measuring the normal incident absorption coefficient in accordance with the ASTM E1050 standard. The results show open porosity as high as 88% was achieved and the effect of water-soluble polymer on cellular properties and acoustic and mechanical performance of the foams was studied. As a result of the secondary porous structure formed into cell walls by water soluble polymer, the overall absorption of fabricated PLA foams was increased to above 90% while the average absorption of the foams remained unchanged. In addition, the resulting acoustic foams are benign and environmentally friendly. © 2013 Wiley Periodicals, Inc. | |||||
BibTeX:
@article{Mosanenzadeh2014, author = {Mosanenzadeh, S.G. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {Development of polylactide open-cell foams with bimodal structure for high-acoustic absorption}, journal = {Journal of Applied Polymer Science}, year = {2014}, volume = {131}, number = {7}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892618333&doi=10.1002%2fapp.39518&partnerID=40&md5=6bc8d580c4dbb016e8197741021f574f}, doi = {https://doi.org/10.1002/app.39518} } |
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Mulligan, K., Quaegebeur, N., Masson, P., Brault, L.-P. and Yang, C. | Compensation of piezoceramic bonding layer degradation for structural health monitoring | 2014 | Structural Health Monitoring Vol. 13(1), pp. 68-81 |
article | DOI URL |
Abstract: The compensation of the degradation of the bonding layer of piezoceramics used in structural health monitoring is addressed in this article. A simple admittance model is first used to measure and extract the variation of admittance parameters using the same acquisition chain which is used by the structural health monitoring system for damage monitoring. More precisely, the method uses measurable changes in physical transducer modal damping at frequencies around piezoceramic resonance to estimate the extent of degradation. Then, a finite element model is used to obtain calibration curves linking the variations in transducer modal damping to amplitude and phase of the ultrasonic signals generated or measured by the piezoceramics. Such calibration curves are obtained by simulating with the FEM the effect of varying the bonding layer coverage area and Young's modulus on (a) admittance and (b) amplitude and phase of the ultrasonic signals. From this, a signal correction factor is developed for the dominant bonding layer coverage area degradation failure mode to compensate for the changes in amplitude and phase of guided waves generated and measured by degraded piezoceramic transducers. The measured modal damping determines the amount of bonding layer degradation from the simulated modal damping calibration curves and then the quantified bonding layer degradation amount selects the amplitude and phase correction to be applied to measured signals from the calibration curves. The benefits of the signal correction factor are demonstrated below piezoceramic resonance to improve damage imaging and localization using the Embedded Ultrasonic Structural Radar algorithm (delay and sum method) when a single transducer in a sparse array of transducers fixed to an aluminum plate is damaged due to the close proximity of drop-weight impacts. Up to a certain damage extent, the signal correction factor could allow an extension of the service life of the structural health monitoring system. © The Author(s) 2013. | |||||
BibTeX:
@article{Mulligan201468, author = {Mulligan, K.R. and Quaegebeur, N. and Masson, P. and Brault, L.-P. and Yang, C.}, title = {Compensation of piezoceramic bonding layer degradation for structural health monitoring}, journal = {Structural Health Monitoring}, year = {2014}, volume = {13}, number = {1}, pages = {68-81}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84891938941&doi=10.1177%2f1475921713500516&partnerID=40&md5=f5bc47781fdda81c18440ae738007648}, doi = {https://doi.org/10.1177/1475921713500516} } |
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Nadeau, J., Boisvert, M. and Micheau, P. | Implementation of a cooperative strategy between a vehicle's mechanical and regenerative brake system | 2014 | 2014 IEEE Vehicle Power and Propulsion Conference, VPPC 2014 | conference | DOI URL |
Abstract: A hybrid vehicle equipped with a hydraulic and a regenerative brake system needs collaboration between both actuators. It is clearly the case, if the pedal input integrates the driver's brake demands. The challenge is to deal with vehicle safety and recovery efficiency. Thus, this work focuses on the implementation of a cooperative braking strategy, involving brake pressure control and regenerative brake control. The objectives are to trade, until limits, the rear wheel friction brake by regenerative brake and to improve the brake performance. To achieve this, this paper proposes a cooperative brake force distribution strategy. For design purpose, a simulator based on empirical results has been developed and the feasibility of the strategy is evaluated through experimentation. © 2014 IEEE. | |||||
BibTeX:
@conference{Nadeau2014, author = {Nadeau, J. and Boisvert, M. and Micheau, P.}, title = {Implementation of a cooperative strategy between a vehicle's mechanical and regenerative brake system}, journal = {2014 IEEE Vehicle Power and Propulsion Conference, VPPC 2014}, year = {2014}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84973645575&doi=10.1109%2fVPPC.2014.7007086&partnerID=40&md5=28ee90f8fcb20a5ba8f79692be62ed09}, doi = {https://doi.org/10.1109/VPPC.2014.7007086} } |
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Nadeau, M., Micheau, P., Robert, R., Vandamme, J., Mousseau, J., Tissier, R., Avoine, O., Germim, P., Sage, M., Praud, J.-P. and Walti, H. | Lumped thermal model of a newborn lamb and a liquid ventilator in total liquid ventilation | 2014 | ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) Vol. 3 |
conference | DOI URL |
Abstract: Total liquid ventilation (TLV) is an emerging and promising mechanical ventilation method in which the lungs are filled with a breathable liquid. Perfluorocarbon (PFC) is the predominant liquid of choice due to its high O2 and CO2 solubility. In TLV, a dedicated liquid ventilator ensures gas exchange by renewing a tidal volume of PFC, which is temperature-controlled, oxygenated and free of CO2. A fundamental difference between TLV and conventional mechanical ventilation relates to the fact that PFCs are approximately 1500 times denser than air. This high density provides PFCs with a large heat capacity, turning the lungs into an efficient heat exchanger with circulating blood. The originality of this study is the development of a lumped thermal model of the body as a heat exchanger coupled to a liquid ventilator. The model was validated with an animal experimentation on a newborn lamb with the Inolivent-5.0 liquid ventilator prototype. TLV was initiated with a fast hypothermia induction, followed successively by a slow posthypothermic rewarming, a fast rewarming and finally a second fast hypothermia induction. Results demonstrate that the model was able to aptly predict, in every phase, the temperature of the lungs, the eardrum, the rectum as well as the various compartments of the liquid ventilator. Copyright © 2014 by ASME. | |||||
BibTeX:
@conference{Nadeau2014, author = {Nadeau, M. and Micheau, P. and Robert, R. and Vandamme, J. and Mousseau, J. and Tissier, R. and Avoine, O. and Germim, P.S. and Sage, M. and Praud, J.-P. and Walti, H.}, title = {Lumped thermal model of a newborn lamb and a liquid ventilator in total liquid ventilation}, journal = {ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)}, year = {2014}, volume = {3}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926500236&doi=10.1115%2fIMECE201440108&partnerID=40&md5=511203070ec9f5ba08ed67cf664302eb}, doi = {https://doi.org/10.1115/IMECE201440108} } |
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Nadeau, M., Micheau, P., Robert, R., Avoine, O., Tissier, R., Germim, P., Vandamme, J., Praud, J.-P. and Walti, H. | Core body temperature control by total liquid ventilation using a virtual lung temperature sensor | 2014 | IEEE Transactions on Biomedical Engineering Vol. 61(12), pp. 2859-2868 |
article | DOI URL |
Abstract: In total liquid ventilation (TLV), the lungs are filled with a breathable liquid perfluorocarbon (PFC) while a liquid ventilator ensures proper gas exchange by renewal of a tidal volume of oxygenated and temperature-controlled PFC. Given the rapid changes in core body temperature generated by TLV using the lung has a heat exchanger, it is crucial to have accurate and reliable core body temperature monitoring and control. This study presents the design of a virtual lung temperature sensor to control core temperature. In the first step, the virtual sensor, using expired PFC to estimate lung temperature noninvasively, was validated both in vitro and in vivo. The virtual lung temperature was then used to rapidly and automatically control core temperature. Experimentations were performed using the Inolivent-5.0 liquid ventilator with a feedback controller to modulate inspired PFC temperature thereby controlling lung temperature. The in vivo experimental protocol was conducted on seven newborn lambs instrumented with temperature sensors at the femoral artery, pulmonary artery, oesophagus, right ear drum, and rectum. After stabilization in conventional mechanical ventilation, TLV was initiated with fast hypothermia induction, followed by slow posthypothermic rewarming for 1 h, then by fast rewarming to normothermia and finally a second fast hypothermia induction phase. Results showed that the virtual lung temperature was able to provide an accurate estimation of systemic arterial temperature. Results also demonstrate that TLV can precisely control core body temperature and can be favorably compared to extracorporeal circulation in terms of speed. © 2014 IEEE. | |||||
BibTeX:
@article{Nadeau20142859, author = {Nadeau, M. and Micheau, P. and Robert, R. and Avoine, O. and Tissier, R. and Germim, P.S. and Vandamme, J. and Praud, J.-P. and Walti, H.}, title = {Core body temperature control by total liquid ventilation using a virtual lung temperature sensor}, journal = {IEEE Transactions on Biomedical Engineering}, year = {2014}, volume = {61}, number = {12}, pages = {2859-2868}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84912123330&doi=10.1109%2fTBME.2014.2332293&partnerID=40&md5=1b897335017fc73b2b3d9f47e3207ebe}, doi = {https://doi.org/10.1109/TBME.2014.2332293} } |
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Ostiguy, P.-C., Quaegebeur, N. and Masson, P. | Improved damage imaging in aerospace structures using a piezoceramic hybrid pin-force wave generation model | 2014 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 9064 |
conference | DOI URL |
Abstract: In this study, a correlation-based imaging technique called « Excitelet » is used to monitor an aerospace grade aluminum plate, representative of an aircraft component. The principle is based on ultrasonic guided wave generation and sensing using three piezoceramic (PZT) transducers, and measurement of reflections induced by potential defects. The method uses a propagation model to correlate measured signals with a bank of signals and imaging is performed using a roundrobin procedure (Full-Matrix Capture). The formulation compares two models for the complex transducer dynamics: one where the shear stress at the tip of the PZT is considered to vary as a function of the frequency generated, and one where the PZT is discretized in order to consider the shear distribution under the PZT. This method allows taking into account the transducer dynamics and finite dimensions, multi-modal and dispersive characteristics of the material and complex interactions between guided wave and damages. Experimental validation has been conducted on an aerospace grade aluminum joint instrumented with three circular PZTs of 10 mm diameter. A magnet, acting as a reflector, is used in order to simulate a local reflection in the structure. It is demonstrated that the defect can be accurately detected and localized. The two models proposed are compared to the classical pin-force model, using narrow and broad-band excitations. The results demonstrate the potential of the proposed imaging techniques for damage monitoring of aerospace structures considering improved models for guided wave generation and propagation. © 2014 SPIE. | |||||
BibTeX:
@conference{Ostiguy2014, author = {Ostiguy, P.-C. and Quaegebeur, N. and Masson, P.}, title = {Improved damage imaging in aerospace structures using a piezoceramic hybrid pin-force wave generation model}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2014}, volume = {9064}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901992575&doi=10.1117%2f12.2045073&partnerID=40&md5=549ec48857581b6e15cfddc322adbc90}, doi = {https://doi.org/10.1117/12.2045073} } |
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Ostiguy, P.-C., Le Duff, A., Quaegebeur, N., Brault, L.-P. and Masson, P. | In situ characterization technique to increase robustness of imaging approaches in structural health monitoring using guided waves | 2014 | Structural Health Monitoring Vol. 13(5), pp. 525-536 |
article | DOI URL |
Abstract: The performance of guided wave imaging strategies used in Structural Health Monitoring relies on the accurate knowledge of mechanical properties for proper damage detection and localization. In order to increase the performance and robustness of such algorithms, it is desirable to implement autonomous approaches that can characterize the mechanical properties of the structure whatsoever the environmental and operational conditions. This article presents an innovative in situ and integrated characterization procedure based on guided waves that evaluates the thermo-mechanical properties of a structure when subjected to thermal variations prior to imaging using the same set of piezoceramic transducers used for imaging. These properties are then exploited in the damage imaging using a correlation-based algorithm (Excitelet) combined with the optimal baseline subtraction. The characterization strategy uses a genetic algorithm to identify the optimal set of mechanical properties leading to the best correlation between an analytical formulation of dispersed guided waves propagation and experimental measurements. The strategy is assessed experimentally on an aluminum plate with three sparse bonded piezoceramic transducers used for both characterization and imaging at various temperatures, representative of operational conditions of an aircraft. An artificial damage is subsequently introduced in the plate, and the effect of the accuracy of the mechanical properties estimation on imaging is assessed through the detection capability, positioning, accuracy, and correlation amplitude. The approach is then compared to three imaging methods, namely, baseline-free imaging, imaging without considering thermo-mechanical effects, and imaging using stretching methods traditionally used to compensate for temperature effects. © The Author(s) 2014. | |||||
BibTeX:
@article{Ostiguy2014525, author = {Ostiguy, P.-C. and Le Duff, A. and Quaegebeur, N. and Brault, L.-P. and Masson, P.}, title = {In situ characterization technique to increase robustness of imaging approaches in structural health monitoring using guided waves}, journal = {Structural Health Monitoring}, year = {2014}, volume = {13}, number = {5}, pages = {525-536}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84906731774&doi=10.1177%2f1475921714532988&partnerID=40&md5=a707517b0c4b97681ec8b377899ec6eb}, doi = {https://doi.org/10.1177/1475921714532988} } |
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Ostiguy, P.-C., Quaegebeur, N. and Masson, P. | Damage detection, localization and size estimation using broadband correlation-based imaging | 2014 | 7th European Workshop on Structural Health Monitoring, EWSHM 2014 - 2nd European Conference of the Prognostics and Health Management (PHM) Society, pp. 591-598 | conference | URL |
Abstract: Imaging approaches based on guided waves aim at detecting, locating and estimating the damage severity on a structure. The actual limitations of imaging approaches are that (1) sensitivity do damage depends on frequency used, and (2) the damage growth can be observed but not yet quantified. This paper presents a robust methodology for damage imaging and size estimation using reconstructed broadband signals, where measurements of the transfer function between each emitter and receiver are made using a sub-band decomposition strategy. Pristine transfer function is subtracted from damage transfer function signature. Imaging is conducted using a correlation-based approach (Excitelet), and dispersion compensation with reconstructed broadband signals. The approach is validated experimentally on a 1.54 mm thick aluminium plate, where only three piezoceramic transducers are bonded on the structure. Measurements are taken for two artificial damage of 13 mm and accurate detection and dimensioning is achieved. The analysis of the transfer functions using the A0 mode shows that the wavelengths reflecting most of the energy are associated to the damage size within an accuracy of one millimetre. Copyright © Inria (2014). | |||||
BibTeX:
@conference{Ostiguy2014591, author = {Ostiguy, P.-C. and Quaegebeur, N. and Masson, P.}, title = {Damage detection, localization and size estimation using broadband correlation-based imaging}, journal = {7th European Workshop on Structural Health Monitoring, EWSHM 2014 - 2nd European Conference of the Prognostics and Health Management (PHM) Society}, year = {2014}, pages = {591-598}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939454759&partnerID=40&md5=b1319da1225b46d4d807ec48c1855896} } |
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Padois, T., Gauthier, P.-A. and Berry, A. | Inverse problem with beamforming regularization matrix applied to sound source localization in closed wind-tunnel using microphone array | 2014 | Journal of Sound and Vibration Vol. 333(25), pp. 6858-6868 |
article | DOI URL |
Abstract: Microphone arrays have become a standard technique to localize and quantify source in aeroacoustics. The simplest approach is the beamforming that provides noise source maps with large main lobe and strong side lobes at low frequency. Since a decade, the focus is set on deconvolution techniques such as DAMAS or Clean-SC. While the source map is clearly improved, these methods require a large computation time. In this paper, we propose a sound source localization technique based on an inverse problem with beamforming regularization matrix called Hybrid Method. With synthetic data, we show that the side lobes are removed and the main lobe is narrower. Moreover, if the sound noise source map provided by this method is used as input in the DAMAS process, the number of DAMAS iterations is highly reduced. The Hybrid Method is applied to experimental data obtained in a closed wind-tunnel. In both cases of acoustic or aeroacoustic data, the source is correctly detected. The proposed Hybrid Method is found simple to implement and the computation time is low if the number of scan points is reasonable. © 2014 Elsevier Ltd. | |||||
BibTeX:
@article{Padois20146858, author = {Padois, T. and Gauthier, P.-A. and Berry, A.}, title = {Inverse problem with beamforming regularization matrix applied to sound source localization in closed wind-tunnel using microphone array}, journal = {Journal of Sound and Vibration}, year = {2014}, volume = {333}, number = {25}, pages = {6858-6868}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908145572&doi=10.1016%2fj.jsv.2014.07.028&partnerID=40&md5=5d518cadf5ae7487afdf6d2bc829a202}, doi = {https://doi.org/10.1016/j.jsv.2014.07.028} } |
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Pasco, Y., Guedeney, T., Leung-Tack, A., Berry, A., Moreau, S. and Masson, P. | Active noise control of tonal turbofan noise in aero engines | 2014 | 15th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2014 | conference | URL |
Abstract: Active Noise Control (ANC) of a turbofan engine is introduced using active stator vanes and rings of loudspeakers as control actuators. It involves a unique coupling of two original analytical and numerical models for the primary and secondary sources respectively, and two different control strategies that attempt to independently control the propagative acoustic modes upstream and downstream for the first time. This is done using Singular Values Decomposition (SVD) and Generalized Singular Values Decomposition (GSVD) without any knowledge on the physical form of the acoustic field. Simulation results are shown and it is demonstrated that the GSVD is a great avenue to separate inlet and outlet radiation. | |||||
BibTeX:
@conference{Pasco2014, author = {Pasco, Y. and Guedeney, T. and Leung-Tack, A. and Berry, A. and Moreau, S. and Masson, P.}, title = {Active noise control of tonal turbofan noise in aero engines}, journal = {15th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2014}, year = {2014}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84914129249&partnerID=40&md5=8e0970ef53ec9217d24ed3da8fe201e5} } |
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Pasco, Y., Guédeney, T., Leung-Tack, A., Berry, A. and Moreau, S. | Active noise control simulation of tonal turbofan noise in aero engines | 2014 | 20th AIAA/CEAS Aeroacoustics Conference | conference | URL |
Abstract: Active Noise Control (ANC) of the tonal noise of a turbofan engine is introduced using active stator vanes and rings of loudspeakers as control actuators. It involves a unique coupling of two original analytical and numerical models for the primary and secondary sources respectively, and two different control strategies that attempt to independently control the propagative acoustic modes upstream and downstream for the first time. The primary noise source is based on the analytical model recently developed by De Laborderie that deals with rectilinear cascade responses due to wake-interaction applied in a strip theory framework. Good agreement with both numerical and experimental data is found on the blade pressure jumps. The secondary noise sources induced by the piezo-actuators embedded in the stator blade are shown to behave as compact dipoles that are radiating in an annular duct. The corresponding radiation can be obtained either numerically or analytically. Here the propagation is computed numerically using COMSOL. The noise control strategy can either Singular Values Decomposition (SVD) or Generalized Singular Values Decomposition (GSVD) without any knowledge on the physical form of the acoustic field. Simulation results are shown to achieve some significant tonal noise reduction and it is demonstrated that the GSVD is a great avenue to separate inlet and outlet radiation. | |||||
BibTeX:
@conference{Pasco2014, author = {Pasco, Y. and Guédeney, T. and Leung-Tack, A. and Berry, A. and Moreau, S.}, title = {Active noise control simulation of tonal turbofan noise in aero engines}, journal = {20th AIAA/CEAS Aeroacoustics Conference}, year = {2014}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903890232&partnerID=40&md5=d584598f28bd35da8d14d351483f3734} } |
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Pasco, Y., Berry, A., Grewal, A. and Chapleau, S. | Active control of transmission noise in a Bell 407 helicopter | 2014 | Annual Forum Proceedings - AHS International Vol. 1, pp. 174-182 |
conference | URL |
Abstract: Cabin noise is a major source of discomfort for helicopter passengers. One of the main sources of noise is the main rotor drive and gearbox assembly, whose structural vibrations are primarily transmitted through supporting struts and mounts to the airframe, which then radiates sound into the cabin. The vibration and resulting noise occur mainly at discrete gear meshing frequencies in the frequency range [1-3] kHz. The objective of this work was to establish the feasibility of an active control system to reduce multi-harmonic transmission noise in helicopter cabins. The system development, implementation and testing were conducted on a Bell 407 aircraft. Copyright© 2014 by the American Helicopter Society International, Inc. All rights reserved. | |||||
BibTeX:
@conference{Pasco2014174, author = {Pasco, Y. and Berry, A. and Grewal, A. and Chapleau, S.L.}, title = {Active control of transmission noise in a Bell 407 helicopter}, journal = {Annual Forum Proceedings - AHS International}, year = {2014}, volume = {1}, pages = {174-182}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84906701590&partnerID=40&md5=bdab96890ea6b5892eaf84b480641ede} } |
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Pelland-Leblanc, J.-P., Lépine, J., Champoux, Y. and Drouet, J.-M. | Effect of structural damping on vibrations transmitted to road cyclists | 2014 | Conference Proceedings of the Society for Experimental Mechanics Series Vol. 7, pp. 283-290 |
conference | DOI URL |
Abstract: Improving ride quality is a paramount concern for road cyclists who are subjected to road induced vibrations during long rides. It has been hypothesized that adding structural damping to the bicycle can decrease the vibration levels transmitted to the cyclist. The human body is most sensitive to vibrations in the frequency range of 0–60 Hz, and the amount of damping added by the cyclist when riding the bicycle is very large. This could potentially reduce the net benefit of small improvements provided by structural damping. This paper reveals the effects of structural damping modifications on the modal parameters of a bicycle frame and on the amount of vibrations transmitted to the cyclist due to road surface excitation. A bicycle frame originally designed with damping gel inserts was tested in three different configurations: (1) with its damping gel inserts, (2) with its damping gel inserts and additional damping material wrapped around the frame’s tubing and (3) without its damping gel inserts. Three different metrics were used to assess the damping material effect on vibrations transmitted to the cyclist at the hands and buttocks: acceleration, transmitted force and power absorbed by the cyclist. This paper shows that in all configurations and measurements, added damping did not reduce the vibrations transmitted to the cyclist. © The Society for Experimental Mechanics, Inc. 2014. | |||||
BibTeX:
@conference{Pelland-Leblanc2014283, author = {Pelland-Leblanc, J.-P. and Lépine, J. and Champoux, Y. and Drouet, J.-M.}, title = {Effect of structural damping on vibrations transmitted to road cyclists}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2014}, volume = {7}, pages = {283-290}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988732062&doi=10.1007%2f978-3-319-04753-9_29&partnerID=40&md5=f11a55184e3305a5905c18d0b5c420cd}, doi = {https://doi.org/10.1007/978-3-319-04753-9_29} } |
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Pelland-Leblanc, J.-P., Lépine, J., Champoux, Y. and Drouet, J.-M. | Using power as a metric to quantify vibration transmitted to the cyclist | 2014 | Procedia Engineering Vol. 72, pp. 392-397 |
conference | DOI URL |
Abstract: For the purposes of new product development, the cycling industry requires an objective means of ranking bicycle comfort with regard to vibration response. Acceleration is currently the standard metric used in the industry. Absorbed power and transmitted force have recently been proposed as metrics to quantify bicycle comfort. The objective of this paper is to compare the relative merits of these 3 metrics. Measurements were done while comparing 2 bikes tested on a cobblestone road and on a laboratory simulator. Acceleration and absorbed power give the same anticipated results but the absorbed power has several advantages over the other metrics. © 2014 Published by Elsevier Ltd. | |||||
BibTeX:
@conference{Pelland-Leblanc2014392, author = {Pelland-Leblanc, J.-P. and Lépine, J. and Champoux, Y. and Drouet, J.-M.}, title = {Using power as a metric to quantify vibration transmitted to the cyclist}, journal = {Procedia Engineering}, year = {2014}, volume = {72}, pages = {392-397}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903779047&doi=10.1016%2fj.proeng.2014.06.067&partnerID=40&md5=9da2ca101895cbc494b4cdc11eac67db}, doi = {https://doi.org/10.1016/j.proeng.2014.06.067} } |
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Pelletier, A., Micheau, P. and Berry, A. | Implementation of a self-sensing piezoelectric actuator for vibro-acoustic active control | 2014 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 9061 |
conference | DOI URL |
Abstract: Significant reduction of airplane interior noise may be obtained by active structural acoustic control (ASAC) of fuselage panels. This requires to accurately measure the vibrations of the aircraft panels while injecting anti-vibrations. Co-located piezoelectric sensors and actuators, spatially distributed on the structure, are an interesting avenue since they can lead to the implementation of distributed virtual impedances. When the same piezoelectric device is used to simultaneously measure and actuate, it is called a self-sensing piezoelectric actuator (SSPA). When a SSPA is submitted to a voltage, the measured current is the sum of the electric current due to the capacitive effect of the transducer plus the mechanical current induced by the strain of the structure. The latter is an order of magnitude smaller than the total current measured. Provided the measured current is digitized with sufficient accuracy, adequate numerical processing can subtract the capacitive current from the total measured current. A similar processing can also be used to subtract from the sensor information, near-field vibrations induced by the collocated actuator. Hence, information related to the global, vibrational flexural modes of the plate is extracted without complicated electronics. The numerical method of current separation has been programmed and validated with MATLAB/SimulinkR® and implemented on Speedgoat hardware. A shunt resistor is used to measure the current simultaneously with the voltage measurement. Strain-induced current has been successfully extracted from SSPA signal with this method. Numerical simulations show good agreement with experimental data. © 2014 SPIE. | |||||
BibTeX:
@conference{Pelletier2014, author = {Pelletier, A. and Micheau, P. and Berry, A.}, title = {Implementation of a self-sensing piezoelectric actuator for vibro-acoustic active control}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2014}, volume = {9061}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84902137168&doi=10.1117%2f12.2044550&partnerID=40&md5=2be80b02e646affa7695b40d502bfcb6}, doi = {https://doi.org/10.1117/12.2044550} } |
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Perrier, S., Champoux, Y. and Drouet, J.-M. | Integrating biodynamic measurements in frequency-based substructuring to study human-structure interaction | 2014 | Conference Proceedings of the Society for Experimental Mechanics Series Vol. 36(2) |
conference | URL |
Abstract: The mechanical behavior of the human body has long been characterized using biodynamic measurements on various human body parts in several positions and postures. Generally, these measurements are gathered as close as possible to the skin-mechanical structure interface for best results understanding how the body reacts when in contact with a vibrating structure. Substructuring methods have been widely used on mechanical structures to study and improve the dynamic behavior of complex assemblies. In the case of interactions between a human body and a vibrating structure, the dynamics involved in the structure alone is as important as the dynamics of the human body. Thus, the use of FrequencyBased Substructuring (FBS) to combine biodynamic measurements with the structure's dynamic behavior is essential to understanding the vibration transmission phenomena in this complex assembly. This article presents the advantages of this approach as well as the challenges when performing FBS between a mechanical structure and biodynamic measurements. The study focuses on a vibrating handlebar in conjunction with 3 different holding positions of the hand-arm system. The FBS assemblies are gathered and the results are compared with experimental measurements on the entire assembled structure for each position over a frequency range between 1 and 100 Hz. © The Society for Experimental Mechanics, Inc. 2014. | |||||
BibTeX:
@conference{Perrier2014, author = {Perrier, S. and Champoux, Y. and Drouet, J.-M.}, title = {Integrating biodynamic measurements in frequency-based substructuring to study human-structure interaction}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2014}, volume = {36}, number = {2}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883177438&partnerID=40&md5=ea82a588c63eacdd0069c87a041e69fd} } |
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Perrier, S., Champoux, Y. and Drouet, J.-M. | Integrating biodynamic measurements in frequency-based substructuring to study human-structure interaction | 2014 | Topics in Experimental Dynamic Substructuring - Proceedings of the 31st IMAC, A Conference on Structural Dynamics, 2013 Vol. 2, pp. 1-8 |
conference | DOI URL |
Abstract: The mechanical behavior of the human body has long been characterized using biodynamic measurements on various human body parts in several positions and postures. Generally, these measurements are gathered as close as possible to the skin-mechanical structure interface for best results understanding how the body reacts when in contact with a vibrating structure. Substructuring methods have been widely used on mechanical structures to study and improve the dynamic behavior of complex assemblies. In the case of interactions between a human body and a vibrating structure, the dynamics involved in the structure alone is as important as the dynamics of the human body. Thus, the use of Frequency-Based Substructuring (FBS) to combine biodynamic measurements with the structure's dynamic behavior is essential to understanding the vibration transmission phenomena in this complex assembly. This article presents the advantages of this approach as well as the challenges when performing FBS between a mechanical structure and biodynamic measurements. The study focuses on a vibrating handlebar in conjunction with 3 different holding positions of the hand-arm system. The FBS assemblies are gathered and the results are compared with experimental measurements on the entire assembled structure for each position over a frequency range between 1 and 100 Hz. © The Society for Experimental Mechanics, Inc. 2014. | |||||
BibTeX:
@conference{Perrier20141, author = {Perrier, S. and Champoux, Y. and Drouet, J.-M.}, title = {Integrating biodynamic measurements in frequency-based substructuring to study human-structure interaction}, journal = {Topics in Experimental Dynamic Substructuring - Proceedings of the 31st IMAC, A Conference on Structural Dynamics, 2013}, year = {2014}, volume = {2}, pages = {1-8}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881388513&doi=10.1007%2f978-1-4614-6540-9_1&partnerID=40&md5=f071ef5c9cf7bcc3b14657131aac286a}, doi = {https://doi.org/10.1007/978-1-4614-6540-9_1} } |
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Quaegebeur, N., Ostiguy, P. and Masson, P. | Correlation-based imaging technique for fatigue monitoring of riveted lap-joint structure | 2014 | Smart Materials and Structures Vol. 23(5) |
article | DOI URL |
Abstract: In the present study, a correlation-based imaging technique called Excitelet is assessed to monitor fatigue crack propagation in a riveted aluminum lap-joint, representative of an aircraft component. For this purpose, a micro-machined piezoceramic array is used to generate guided waves into the structure and measure the reflections induced by potential damage. The method uses a propagation model to correlate measured signals with a bank of signals and imaging is performed using a round-robin procedure (full-matrix capture). This allows taking into account the transducer dynamics and finite dimensions, multi-modal and dispersive characteristics of the guided wave propagation and complex interaction between with damage. Experimental validation has been conducted on an aluminum lap-joint instrumented with a compact linear piezoceramic array of 8 circular elements of 3 mm diameter each. The imaging technique is applied to detect crack propagation after fatigue cycling. Imaging results obtained using A0 mode at 300 and 450 kHz are presented for different crack sizes. It is demonstrated that crack detection and localization can be achieved, while the correlation level indicates the level of reflected energy, and thus damage severity. An accuracy below 5 mm on damage location can be achieved, demonstrating the potential of the correlation-based imaging technique for damage monitoring of complex aerospace structures. © 2014 IOP Publishing Ltd. | |||||
BibTeX:
@article{Quaegebeur2014, author = {Quaegebeur, N. and Ostiguy, P.C. and Masson, P.}, title = {Correlation-based imaging technique for fatigue monitoring of riveted lap-joint structure}, journal = {Smart Materials and Structures}, year = {2014}, volume = {23}, number = {5}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84898455235&doi=10.1088%2f0964-1726%2f23%2f5%2f055007&partnerID=40&md5=955ddaf5842dca68b7fa90b90c270ab0}, doi = {https://doi.org/10.1088/0964-1726/23/5/055007} } |
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Quaegebeur, N., Ostiguy, P.-C. and Masson, P. | Use of two-dimensional stress in the modelling of guided wave generation by circular piezoceramics | 2014 | 7th European Workshop on Structural Health Monitoring, EWSHM 2014 - 2nd European Conference of the Prognostics and Health Management (PHM) Society, pp. 756-763 | conference | URL |
Abstract: Traditional transducer design methods in Structural Health Monitoring based on Guided Wave propagation rely on the use of the pin-force model, assuming that a piezoelectric actuator can be modelled as a constant shear stress applied at its edge, whatsoever the frequency generated. However, the assumptions of this model are only validated for in- finitely thin piezoelectric elements, weak coupling between the host structure and the transducer, and when the wavelength of the generated guided wave is above the size of the transducer. In this paper, a three-dimensional analysis of guided wave generation by a circular piezoceramic is proposed, taking into account the complex shear and normal in- terfacial stress profile between the transducer and the host structure. The complex stress profile is extracted from a Finite Element Model and then used as a parameter in the analytical propagation formulation. The influence of piezoceramic actuator dimension, thickness and host structure properties is then assessed numerically. Copyright © Inria (2014). | |||||
BibTeX:
@conference{Quaegebeur2014756, author = {Quaegebeur, N. and Ostiguy, P.-C. and Masson, P.}, title = {Use of two-dimensional stress in the modelling of guided wave generation by circular piezoceramics}, journal = {7th European Workshop on Structural Health Monitoring, EWSHM 2014 - 2nd European Conference of the Prognostics and Health Management (PHM) Society}, year = {2014}, pages = {756-763}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939434741&partnerID=40&md5=1fdc6d9a83aad0a854f7322a9194f61d} } |
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Ramanana, T., Gauthier, P.-A., Bolduc, A. and Berry, A. | Sound reproduction by beamforming capture and Wave Field Synthesis | 2014 | Proceedings of the AES International Conference Vol. 2014-January |
conference | URL |
Abstract: In this paper, the reproduction of industrial or vehicle sound environments is investigated. The method relies on the combination of microphone array recording, beamforming, Wave Field Synthesis (WFS), and bass equalization. The approach is based on fixed looking-direction beamformers to separate signals depending on their incoming direction. The beamformer signals are then processed by WFS in order to recreate the sound environment as multiple plane waves. A theoretical parametric study based on the number of beamformer steering directions is provided. Comparisons of the target and reproduced sound environments are reported in order to identify appropriate system parameters for the reproduction of sound environments as found in vehicle or industrial contexts. Copyright © Audio Engineering Society 2014. | |||||
BibTeX:
@conference{Ramanana2014, author = {Ramanana, T. and Gauthier, P.-A. and Bolduc, A. and Berry, A.}, title = {Sound reproduction by beamforming capture and Wave Field Synthesis}, journal = {Proceedings of the AES International Conference}, year = {2014}, volume = {2014-January}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938826013&partnerID=40&md5=7a14d982b600cb23a6afed133514568b} } |
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Rhazi, D. and Atalla, N. | Acoustic and vibration response of a structure with added noise control treatment under various excitations | 2014 | Journal of the Acoustical Society of America Vol. 135(2), pp. 693-704 |
article | DOI URL |
Abstract: The evaluation of the acoustic performance of noise control treatments is of great importance in many engineering applications, e.g., aircraft, automotive, and building acoustics applications. Numerical methods such as finite- and boundary elements allow for the study of complex structures with added noise control treatment. However, these methods are computationally expensive when used for complex structures. At an early stage of the acoustic trim design process, many industries look for simple and easy to use tools that provide sufficient physical insight that can help to formulate design criteria. The paper presents a simple and tractable approach for the acoustic design of noise control treatments. It presents and compares two transfer matrix-based methods to investigate the vibroacoustic behavior of noise control treatments. The first is based on a modal approach, while the second is based on wave-number space decomposition. In addition to the classical rain-on-the-roof and diffuse acoustic field excitations, the paper also addresses turbulent boundary layer and point source (monopole) excitations. Various examples are presented and compared to a finite element calculation to validate the methodology and to confirm its relevance along with its limitations. © 2014 Acoustical Society of America. | |||||
BibTeX:
@article{Rhazi2014693, author = {Rhazi, D. and Atalla, N.}, title = {Acoustic and vibration response of a structure with added noise control treatment under various excitations}, journal = {Journal of the Acoustical Society of America}, year = {2014}, volume = {135}, number = {2}, pages = {693-704}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900455691&doi=10.1121%2f1.4861361&partnerID=40&md5=0b9297e73fc173c416fe55b47bae1270}, doi = {https://doi.org/10.1121/1.4861361} } |
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Robert, R., Micheau, P., Nadeau, M., Vandamme, J., Mousseau, J., Avoine, O., Sage, M., Praud, J.-P. and Walti, H. | Virtual airway pressure and lung temperature sensors in a total liquid ventilation connector | 2014 | ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) Vol. 3 |
conference | DOI URL |
Abstract: Total liquid ventilation (TLV) is an experimental mechanical ventilation technique where the lungs are completely filled with a perfluorocarbon liquid (PFC). It can be used to implement moderate therapeutic hypothermia (MTH) and treat severe respiratory problems. During TLV, the airway pressure must be monitored adequately to avoid overpressure and airway collapses. On the thermodynamic level, rectal, esophageal or tympanic temperature measurements are not suitable (long time constant) to avoid lowering the heart below 30°C. The objective was to design a Y connector positioned at the mouth which integrates the virtual sensors, used by controllers. The first estimates the airway pressure and the second provides the core body temperature. Pressure and RTD sensors were installed in the connector to implement the virtual measurements. In-vitro experiments were done to validate the virtual sensors. In-vivo experiments (on newborn lambs) confirm the accuracy of the airway pressure estimation and of the systemic arterial temperature. Copyright © 2014 by ASME. | |||||
BibTeX:
@conference{Robert2014, author = {Robert, R. and Micheau, P. and Nadeau, M. and Vandamme, J. and Mousseau, J. and Avoine, O. and Sage, M. and Praud, J.-P. and Walti, H.}, title = {Virtual airway pressure and lung temperature sensors in a total liquid ventilation connector}, journal = {ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)}, year = {2014}, volume = {3}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926443482&doi=10.1115%2fIMECE201440070&partnerID=40&md5=3fb66a39fd1bf4fb72476e1e604272e4}, doi = {https://doi.org/10.1115/IMECE201440070} } |
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Robin, O., Berry, A., Doutres, O. and Atalla, N. | Measurement of the absorption coefficient of sound absorbing materials under a synthesized diffuse acoustic field | 2014 | Journal of the Acoustical Society of America Vol. 136(1), pp. EL13-EL19 |
article | DOI URL |
Abstract: This letter proposes an experimental method to estimate the absorption coefficient of sound absorbing materials under a synthesized diffuse acoustic field in free-field conditions. Comparisons are made between experiments conducted with this approach, the standard reverberant room method, and numerical simulations using the transfer matrix method. With a simple experimental setup and smaller samples than those required by standards, the results obtained with the proposed approach do not exhibit non-physical trends of the reverberant room method and provide absorption coefficients in good agreement with those obtained by simulations for a laterally infinite material. © 2014 Acoustical Society of America. | |||||
BibTeX:
@article{Robin2014, author = {Robin, O. and Berry, A. and Doutres, O. and Atalla, N.}, title = {Measurement of the absorption coefficient of sound absorbing materials under a synthesized diffuse acoustic field}, journal = {Journal of the Acoustical Society of America}, year = {2014}, volume = {136}, number = {1}, pages = {EL13-EL19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903986755&doi=10.1121%2f1.4881321&partnerID=40&md5=2cd971284778842f74db843376230c42}, doi = {https://doi.org/10.1121/1.4881321} } |
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Robin, O., Berry, A. and Moreau, S. | Experimental vibroacoustic testing of plane panels using synthesized random pressure fields | 2014 | Journal of the Acoustical Society of America Vol. 135(6), pp. 3434-3445 |
article | DOI URL |
Abstract: The experimental reproduction of random pressure fields on a plane panel and corresponding induced vibrations is studied. An open-loop reproduction strategy is proposed that uses the synthetic array concept, for which a small array element is moved to create a large array by post-processing. Three possible approaches are suggested to define the complex amplitudes to be imposed to the reproduction sources distributed on a virtual plane facing the panel to be tested. Using a single acoustic monopole, a scanning laser vibrometer and a baffled simply supported aluminum panel, experimental vibroacoustic indicators such as the Transmission Loss for Diffuse Acoustic Field, high-speed subsonic and supersonic Turbulent Boundary Layer excitations are obtained. Comparisons with simulation results obtained using a commercial software show that the Transmission Loss estimation is possible under both excitations. Moreover and as a complement to frequency domain indicators, the vibroacoustic behavior of the panel can be studied in the wave number domain. © 2014 Acoustical Society of America. | |||||
BibTeX:
@article{Robin20143434, author = {Robin, O. and Berry, A. and Moreau, S.}, title = {Experimental vibroacoustic testing of plane panels using synthesized random pressure fields}, journal = {Journal of the Acoustical Society of America}, year = {2014}, volume = {135}, number = {6}, pages = {3434-3445}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903192161&doi=10.1121%2f1.4872298&partnerID=40&md5=dcc7d43462f67817c6b11cc2a6f45632}, doi = {https://doi.org/10.1121/1.4872298} } |
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Sherafat, M., Quaegebeur, N., Lessard, L., Hubert, P. and Masson, P. | Guided wave propagation through composite bonded joints | 2014 | 7th European Workshop on Structural Health Monitoring, EWSHM 2014 - 2nd European Conference of the Prognostics and Health Management (PHM) Society, pp. 1871-1877 | conference | URL |
Abstract: Bonding of composite structures is regularly used in aerospace industry to restore structural integrity in repair or assemble sub-structures. This structural feature is prone to degradation with improper installation or disbond when submitted to fatigue or extreme strains. Therefore, non-destructive evaluation (NDE) should be considered to inspect adhesive bonded joints. In comparision with traditional NDE, a built-in structural health monitoring (SHM) would be more desirable to save the inspection cost as well as improve safety. The objective of this research is to evaluate integrity of composite bonded joints using guided wave propagation technique. Two carbon fiber reinforced polymer (CFRP) are bonded together using adhesive film and artificial disbond is introduced by a circular Teflon tape. A rectangular piezoceramic is used to generate plane guided waves and non-contact measurement is performed using 3-D Laser Doppler Vibrometer to extract the required information for evaluation of quality of bond line. Results have shown that the joint can be charactized using guided wave behavior; and reflection and transmision coefficients for incident A |
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BibTeX:
@conference{Sherafat20141871, author = {Sherafat, M.H. and Quaegebeur, N. and Lessard, L. and Hubert, P. and Masson, P.}, title = {Guided wave propagation through composite bonded joints}, journal = {7th European Workshop on Structural Health Monitoring, EWSHM 2014 - 2nd European Conference of the Prognostics and Health Management (PHM) Society}, year = {2014}, pages = {1871-1877}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939419591&partnerID=40&md5=46428a39c90003b0c568e8614c25da0a} } |
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Verdière, K., Panneton, R., Elkoun, S., Dupont, T. and Leclaire, P. | Comparison between parallel transfer matrix method and admittance sum method | 2014 | Journal of the Acoustical Society of America Vol. 136(2), pp. EL90-EL95 |
article | DOI URL |
Abstract: A transfer matrix method to predict absorption coefficient and transmission loss of parallel assemblies of materials which can be expressed by a 2 × 2 transfer matrix was published recently. However, the usual method based on the sum of admittances is largely used to predict also surface admittance of parallel assemblies. This paper aims to highlight differences between both methods through three examples on a parallel assembly backed by (1) a rigid wall, (2) an air cavity, and (3) an anechoic termination. © 2014 Acoustical Society of America. | |||||
BibTeX:
@article{Verdière2014, author = {Verdière, K. and Panneton, R. and Elkoun, S. and Dupont, T. and Leclaire, P.}, title = {Comparison between parallel transfer matrix method and admittance sum method}, journal = {Journal of the Acoustical Society of America}, year = {2014}, volume = {136}, number = {2}, pages = {EL90-EL95}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84905679203&doi=10.1121%2f1.4885481&partnerID=40&md5=84c43de409620af2bfb37bd2693b92a8}, doi = {https://doi.org/10.1121/1.4885481} } |
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Alimonti, L., Atalla, N., Berry, A. and Sgard, F. | A hybrid modeling approach for vibroacoustic systems with attached sound packages | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: Modeling complex vibroacoustic systems including poroelastic materials using Finite Element (FE) based methods can be computationally expensive. Several attempts have been made to alleviate this drawback, such as high order hierarchical basis and substructuring approaches. Still, these methods remain computationally expensive or limited to simple configurations. On the other hand, analytical approaches, such as the Transfer Matrix Method (TMM), are often used thanks to the lower computational burden. However, since the geometrical flexibility of the FE method is always needed in the low/mid-frequency range, attempts have been made to couple a FE model of the elastic and acoustic domains with a TM model of the sound package. Although these hybrid approaches seem promising, the open literature is not comprehensive. The aim of this work is to present a hybrid FE-TMM approach based on a Green's function formulation. The idea is to account for the sound package by approximating the self and mutual effects on the FE nodes at the interface using fundamental solutions (i.e. Green's functions) obtained by the TMM. A benchmark representative of typical applications is used to illustrate the capabilities of the presented methodology in terms of efficiency and accuracy in comparison to other classical methods. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Alimonti2013, author = {Alimonti, L. and Atalla, N. and Berry, A. and Sgard, F.}, title = {A hybrid modeling approach for vibroacoustic systems with attached sound packages}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878979144&doi=10.1121%2f1.4799706&partnerID=40&md5=2122771d4022442e509fc78b6ea7acc9}, doi = {https://doi.org/10.1121/1.4799706} } |
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Alimonti, L., Atalla, N., Berry, A. and Sgard, F. | Assessment of the accuracy of a hybrid finite element- Transfer matrix based model for vibroacoustic systems including poroealstic materials | 2013 | 42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life Vol. 4, pp. 3299-3308 |
conference | URL |
Abstract: Modeling complex vibroacoustic systems including poroelastic materials using Finite Element (FE) based methods can be computationally expensive. For this reason, fast analytical approaches, such as the Tranfer Matrix Method (TMM), are often preferred to such sophisticated numerical techniques. However, analytical methodologies suffer from a lack of accuracy in the description of the geometry of the system. To alleviate this drawback, attempts have been made to couple a FE model of the elastic and acoustic domains with a TM model of the sound package. The authors recently proposed a hybrid methodology based on a Green's function formulation to account for sound packages in FE models. Although this hybrid methodology seems capable of capturing the physics better than classical approaches, the simplifications introduced by the analytical model can, in some cases, lead to an erroneous estimation of the vibroacoustic performance. In this work, the limitations of the methodology are assessed. A benchmark of typical vibroacoustic systems is presented to show the misbehavior of the hybrid model by a comparison with the FE solution. This lack of accuracy is due to the assumption of an infinite extent sound package inherent within the TMM. Copyright © (2013) by Austrian Noise Abatement Association (OAL). | |||||
BibTeX:
@conference{Alimonti20133299, author = {Alimonti, L. and Atalla, N. and Berry, A. and Sgard, F.}, title = {Assessment of the accuracy of a hybrid finite element- Transfer matrix based model for vibroacoustic systems including poroealstic materials}, journal = {42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life}, year = {2013}, volume = {4}, pages = {3299-3308}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84904463163&partnerID=40&md5=978a7354e39f05381f091caf1fb89873} } |
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Blais, J.-F., Camier, C., Dufour, M., Lapointe, R., Provencher, J., Padois, T., Gauthier, P.-A. and Berry, A. | Flyover aircraft noise measurement campaign at Montreal-Trudeau airport using a microphone array | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: Engines being quieter due to high by-pass ratios, the airframe noise, produced for instance by landing gears or high-lift devices, has become a significant contributor to the total noise radiated by aircraft during approach and landing. As part of the investigations carried out to understand noise generation mechanisms, the beamforming techniques developed over the last decade and applied to microphone array measurements have shown to be effective tools for localization and quantification of these aerodynamic noise sources. In order to validate their in-house beamforming softwares, Bombardier Aerospace and the Groupe d'Acoustique de l'Université de Sherbrooke have conducted a 5-day measurement campaign in June 2012. The 95-microphone array was located on the roof of a building next to the Montreal-Trudeau airport. Aircraft position was determined by two high-definition cameras, both synchronized with the microphone array by inter-range instrumentation group time codes generators. This paper summarizes the measurement campaign. The aircraft tracking tool and the beamforming algorithms used to characterize the noise sources are presented. Several Bombardier CRJ fly-overs were recorded during this test. Beamforming results obtained for different airlines are compared in order to evaluate the repeatability of the method. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Blais2013, author = {Blais, J.-F. and Camier, C. and Dufour, M.P. and Lapointe, R. and Provencher, J. and Padois, T. and Gauthier, P.-A. and Berry, A.}, title = {Flyover aircraft noise measurement campaign at Montreal-Trudeau airport using a microphone array}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878995506&doi=10.1121%2f1.4800879&partnerID=40&md5=2025e0f4a2ebaacf66b8d0e03fe0ed73}, doi = {https://doi.org/10.1121/1.4800879} } |
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Boisvert, M., Mammosser, D., Micheau, P. and Desrochers, A. | Comparison of two strategies for optimal regenerative braking, with their sensitivity to variations in mass, slope and road condition | 2013 | IFAC Proceedings Volumes (IFAC-PapersOnline) Vol. 7(PART 1), pp. 626-630 |
conference | DOI URL |
Abstract: A three wheels recreational vehicle is studied for the purpose of regenerative braking control. Most of the existing literature propose optimal methods which consist in defining the braking torque as a function of the vehicle speed. The originality of this study is to propose a new strategy based on the control of the rear wheel slip. A simulator based on Matlab/Simulink and validated with experimental measurements compares the two strategies and their sensitivities to variation in mass, slope and road condition. Numerical simulations show that the regenerative braking based on a slip controller is less affected by parametric changes. It thus becomes possible to ensure optimal recovery of energy and vehicle stability even in case of parametric fluctuations. | |||||
BibTeX:
@conference{Boisvert2013626, author = {Boisvert, M. and Mammosser, D. and Micheau, P. and Desrochers, A.}, title = {Comparison of two strategies for optimal regenerative braking, with their sensitivity to variations in mass, slope and road condition}, journal = {IFAC Proceedings Volumes (IFAC-PapersOnline)}, year = {2013}, volume = {7}, number = {PART 1}, pages = {626-630}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885909208&doi=10.3182%2f20130904-4-JP-2042.00129&partnerID=40&md5=4a37a2b3377580ef6ac77e85d74ef316}, doi = {https://doi.org/10.3182/20130904-4-JP-2042.00129} } |
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Camier, C., Padois, T., Provencher, J., Gauthier, P.-A., Berry, A., Blais, J.-F., Patenaude-Dufour, M. and Lapointe, R. | Fly-over source localization on civil aircraft | 2013 | 19th AIAA/CEAS Aeroacoustics Conference, pp. 246 | conference | URL |
Abstract: In June 2012, fly-over measurements were performed on landing aircraft at P.-E. Trudeau Montréal airport. A custom-made measurement system developed by GAUS (Groupe d'Acoustique de l'Université de Sherbrooke) including a 95-microphone array with its related audio pre-amplifying and recording system have been used to acquire a comprehensive data set of over 300 flyovers during a five-day period. A particular focus has been made on Bombardier CRJ200 aircraft for which several flight conditions have been measured. Trajectories of aircraft were tracked by a synchronized 2-camera system. Precise localizations of landing gear, flaps and engine have been obtained as preliminary results. The article details source identidification results as well as the complete experimental set-up and the algorithms used in de-dopplerization and Beamforming computations. | |||||
BibTeX:
@conference{Camier2013246, author = {Camier, C. and Padois, T. and Provencher, J. and Gauthier, P.-A. and Berry, A. and Blais, J.-F. and Patenaude-Dufour, M. and Lapointe, R.}, title = {Fly-over source localization on civil aircraft}, journal = {19th AIAA/CEAS Aeroacoustics Conference}, year = {2013}, pages = {246}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883676233&partnerID=40&md5=6bfaca62e11e1fd81cae9e1ea26812f6} } |
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Castaings, M., Leleux, A. and Micheau, P. | Inspection of composite components by pure guided wave based ultrasonic imaging with one phased array probe [BibTeX] |
2013 | ICCM International Conferences on Composite Materials Vol. 2013-July, pp. 4172-4173 |
conference | URL |
BibTeX:
@conference{Castaings20134172, author = {Castaings, M. and Leleux, A. and Micheau, P.}, title = {Inspection of composite components by pure guided wave based ultrasonic imaging with one phased array probe}, journal = {ICCM International Conferences on Composite Materials}, year = {2013}, volume = {2013-July}, pages = {4172-4173}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053209496&partnerID=40&md5=802b60569e8b14bbeacc8c8543a91c73} } |
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Champoux, Y., Lépine, J., Gauthier, P.-A. and Drouet, J.-M. | A laboratory technique to compare road bike dynamic comfort | 2013 | Conference Proceedings of the Society for Experimental Mechanics Series Vol. 6, pp. 99-106 |
conference | DOI URL |
Abstract: Comfort is an important characteristic in road bikes, and a major source of discomfort is the vibration transmitted to the cyclist. Since human memory tends to forget the perceived vibration stimulus strength soon after the perception is no longer present, a comparison between two situations must be done rapidly. Laboratory testing is therefore frequently used to investigate and document perception. This paper presents a laboratory technique enabling us to subject the cyclist to various types of bike vibration stimuli. The technique is based on the use of a bicycle simulator that generates vertical displacement under both wheels of a bike. A commercial bicycle is used to replicate vibration outputs at the saddle and the stem of different bikes. The strategy to determine the appropriate driving signals of each simulator actuator is presented in this paper. This requires solving an inverse problem. The results indicate that the measured and the reproduced PSD spectrum shapes are very similar. The main factor influencing the quality of reproduction is cyclist intervariability. © The Society for Experimental Mechanics, Inc. 2013. | |||||
BibTeX:
@conference{Champoux201399, author = {Champoux, Y. and Lépine, J. and Gauthier, P.-A. and Drouet, J.-M.}, title = {A laboratory technique to compare road bike dynamic comfort}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2013}, volume = {6}, pages = {99-106}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889588161&doi=10.1007%2f978-1-4614-6546-1_11&partnerID=40&md5=29edaed4b4698ee9928a6693a2f94c7e}, doi = {https://doi.org/10.1007/978-1-4614-6546-1_11} } |
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de Laborderie, J., Moreau, S. and Berry, A. | Compressor stage broadband noise prediction using a large-eddy simulation and comparisons with a cascade response model | 2013 | 19th AIAA/CEAS Aeroacoustics Conference, pp. 41 | conference | URL |
Abstract: The present work addresses the rotor-stator interaction broadband noise prediction. The objectives are first to develop a numerical acoustic method and second to deepen the understanding of this noise mechanism to improve an existing analytical model. The two steps of the numerical method consist in performing a Large-Eddy Simulation of an actual rotor-stator stage in order to directly extract the broadband pressure fluctuations on the stator vanes. Then the latter are used as equivalent noise sources in Goldstein acoustic analogy in the frequency domain. An axial flow compressor stage is used as a test case. The mean and unsteady components of the flow are analyzed. The turbulent properties of the flow needed in the analytical model are extracted from the LES. The unsteady pressure on the vanes predicted by the LES exhibits very different behaviors depending on the position on the vane that are attributed to several mechanisms such as turbulent wake interaction or boundary layer transition. The spanwise coherence length representing a crucial parameter for the analytical model is also investigated from the numerical vane response, showing a longer value than the one usually considered in the analytical model. The acoustic power spectra predicted by both approaches are compared and the effect of the spanwise coherence length is studied. | |||||
BibTeX:
@conference{deLaborderie201341, author = {de Laborderie, J. and Moreau, S. and Berry, A.}, title = {Compressor stage broadband noise prediction using a large-eddy simulation and comparisons with a cascade response model}, journal = {19th AIAA/CEAS Aeroacoustics Conference}, year = {2013}, pages = {41}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883660436&partnerID=40&md5=3699d5b63eccac2ea0ce8f7961650898} } |
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Doutres, O., Atalla, N., Brouillette, M., Hébert, C. and Begg, D. | Improving the sound absorbing efficiency of closed-cell foams using shock waves | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: Producing closed-cell foams is generally cheaper and simpler than open-cell foams. However, the acoustic efficiency of closed-cell foam materials is poor because it is very difficult for the acoustic waves to penetrate the material. A method to remove the membranes closing the cell pores (known as reticulations) and thus to improve the acoustic behavior of closed-cell foam material is presented. The method is based on the propagation of shock waves inside the foam aggregate where both the shock wave generator and the foam are in air at room conditions. Various shock treatments have been carried out on a Polyurethane foams and the following conclusions were drawn: (1) the reticulation rate increases and thus the airflow resistivity decreases while increasing the amplitude of the shock treatment; (2) the softness of the foam increases; (3) the process is reliable and repeatable and (4) the obtained acoustic performance is comparable to classical thermal reticulation. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Doutres2013, author = {Doutres, O. and Atalla, N. and Brouillette, M. and Hébert, C. and Begg, D.}, title = {Improving the sound absorbing efficiency of closed-cell foams using shock waves}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878963741&doi=10.1121%2f1.4799702&partnerID=40&md5=fcc983411af26877626a2db9cfb5d125}, doi = {https://doi.org/10.1121/1.4799702} } |
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Doutres, O., Atalla, N. and Dong, K. | A semi-phenomenological model to predict the acoustic behavior of fully and partially reticulated polyurethane foams | 2013 | Journal of Applied Physics Vol. 113(5) |
article | DOI URL |
Abstract: This paper proposes simple semi-phenomenological models to predict the sound absorption efficiency of highly porous polyurethane foams from microstructure characterization. In a previous paper [J. Appl. Phys. 110, 064901 (2011)], the authors presented a 3-parameter semi-phenomenological model linking the microstructure properties of fully and partially reticulated isotropic polyurethane foams (i.e., strut length l, strut thickness t, and reticulation rate Rw) to the macroscopic non-acoustic parameters involved in the classical Johnson-Champoux-Allard model (i.e., porosity f, airflow resistivity s, tortuosity a?, viscous ?, and thermal ?' characteristic lengths). The model was based on existing scaling laws, validated for fully reticulated polyurethane foams, and improved using both geometrical and empirical approaches to account for the presence of membrane closing the pores. This 3-parameter model is applied to six polyurethane foams in this paper and is found highly sensitive to the microstructure characterization; particularly to strut's dimensions. A simplified micro-/macro model is then presented. It is based on the cell size Cs and reticulation rate Rw only, assuming that the geometric ratio between strut length l and strut thickness t is known. This simplified model, called the 2-parameter model, considerably simplifies the microstructure characterization procedure. A comparison of the two proposed semi-phenomenological models is presented using six polyurethane foams being either fully or partially reticulated, isotropic or anisotropic. It is shown that the 2-parameter model is less sensitive to measurement uncertainties compared to the original model and allows a better estimation of polyurethane foams sound absorption behavior. © 2013 American Institute of Physics. | |||||
BibTeX:
@article{Doutres2013, author = {Doutres, O. and Atalla, N. and Dong, K.}, title = {A semi-phenomenological model to predict the acoustic behavior of fully and partially reticulated polyurethane foams}, journal = {Journal of Applied Physics}, year = {2013}, volume = {113}, number = {5}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873649916&doi=10.1063%2f1.4789595&partnerID=40&md5=cf9fd85c333d6cfc64e022d0387e396d}, doi = {https://doi.org/10.1063/1.4789595} } |
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Dupont, T., Leclaire, P., Panneton, R., Verdière, K. and Elkoun, S. | A method for measuring the acoustic properties of a porous sample mounted in a rigid ring in acoustic tubes | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: This study presents a method to measure the acoustic properties of a homogeneous porous material with a support or a reduction element in an acoustic tube. Some materials tested have a lateral size much smaller than the tube's diameter, as they cannot be produced in the correct dimensions without corrupting the material; this also permits the testing of the same samples in a large frequency bandwidth by using different section tubes. Moreover, the acoustic leaks on the material boundaries can significantly change the transmission loss measured in tubes. To rectify these problems, rings can be placed on each material surface. The presence of these rings can influence the acoustic indicator measurement; while this effect is negligible for tubes with a large cross section, it is not for tubes with a small cross section. To correct, or remove, the influence of the rings, we propose to use an application of the parallel assembly process of the transfer matrix method which has recently been proposed by Panneton et al. [Proceeding Internoise New York (2012)]. Measurements on classical porous materials with and without reductions are proposed and compared to simulated results. The ring's effects and the proposed corrections are discussed for different materials. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Dupont2013, author = {Dupont, T. and Leclaire, P. and Panneton, R. and Verdière, K. and Elkoun, S.}, title = {A method for measuring the acoustic properties of a porous sample mounted in a rigid ring in acoustic tubes}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878983180&doi=10.1121%2f1.4799701&partnerID=40&md5=3216ff6639dc50c4bc7de143ff87993e}, doi = {https://doi.org/10.1121/1.4799701} } |
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Dupont, T., Leclaire, P. and Panneton, R. | Acoustic methods for measuring the porosities of porous materials incorporating dead-end pores | 2013 | Journal of the Acoustical Society of America Vol. 133(4), pp. 2136-2145 |
article | DOI URL |
Abstract: The acoustic properties of porous materials containing dead-end (DE) pores have been proposed by Dupont [J. Appl. Phys. 110, 094903 (2011)]. In the theoretical description, two physical parameters were defined (the dead-end porosity and the average length of the dead-end pores). With the knowledge of the open porosity (measured with non-acoustic methods), and the measurement of kinematic porosity (also called the Biot porosity in this article), it is possible to deduce the dead-end porosity. Two acoustic methods for measuring the Biot porosity for a wide range of porosities are proposed. These methods are based on acoustic transmission and on the low and high frequency behaviors of acoustic indicators. The low frequency method is valid for high porosities. It involves measurements in a transmission tube and the knowledge of the theoretical asymptotic behavior of the phase velocity at high frequencies. The high frequency method is based on ultrasonic measurements and on the high frequency asymptotic behavior of the transmission coefficient. It is well adapted for material with relatively low values of porosity. Good precision was found for both methods and materials containing dead end porosity were tested. © 2013 Acoustical Society of America. | |||||
BibTeX:
@article{Dupont20132136, author = {Dupont, T. and Leclaire, P. and Panneton, R.}, title = {Acoustic methods for measuring the porosities of porous materials incorporating dead-end pores}, journal = {Journal of the Acoustical Society of America}, year = {2013}, volume = {133}, number = {4}, pages = {2136-2145}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876142496&doi=10.1121%2f1.4792484&partnerID=40&md5=34c488f00115633e53277ea38244de46}, doi = {https://doi.org/10.1121/1.4792484} } |
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Gauthier, P.-A., Camier, C., Gauthier, O., Pasco, Y. and Berry, A. | Aircraft sound environment reproduction: Sound field reproduction inside a cabin mock-up using microphone and actuator arrays | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: Sound environment reproduction of various flight conditions in aircraft cabin mock-ups is useful for the design, demonstration and jury testing of interior aircraft sound quality. To provide a faithfully perceived sound environment, time, frequency and spatial characteristics should be preserved. Physical sound field reproduction approaches for spatial sound reproduction are mandatory to immerse the listener in the proper sound field so that localization cues are recreated. A 80-channel microphone array was built and used to capture a 2-hour recording of in-flight sound environments within an actual Bombardier CRJ aircraft. An instrumented cabin mock-up was used to reproduce, in the least-mean-square sense, the recorded sound field using a 41-channel trim-panel actuator array. In this paper, experiments with multichannel equalization are reported. One of the practical difficulties was related to the use of the trim panels as sound sources. Windows and trim panels introduce audible squeaks and rattles if driven at low frequencies. Bass management was therefore implemented. Floor shakers and a subwoofer were used to recreate the low frequency content while the trim panels were only used for the high frequency range. The paper presents objective evaluations of reproduced sound fields. Results and practical compromises are reported. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Gauthier2013, author = {Gauthier, P.-A. and Camier, C. and Gauthier, O. and Pasco, Y. and Berry, A.}, title = {Aircraft sound environment reproduction: Sound field reproduction inside a cabin mock-up using microphone and actuator arrays}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878962596&doi=10.1121%2f1.4799025&partnerID=40&md5=9ef05576a2d174567067f2760bbf7070}, doi = {https://doi.org/10.1121/1.4799025} } |
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Gauthier, P.-A., Camier, C., Padois, T., Gauthier, O., Pasco, Y. and Berry, A. | Objective evaluation of sound field and sound environment reproduction in aircraft mock-ups using acoustic imaging | 2013 | Proceedings of the AES International Conference, pp. 129-138 | conference | URL |
Abstract: Audio is also an active topic for acousticians in the aircraft manufacturing industry. Typical concerns are sound quality, noise annoyance or realism, in case of flight simulators. Accordingly, sound field reproduction of real flight conditions in aircraft mock-ups is a valuable tool for jury testing, listening test or marketing purposes. Recently, a cabin mock-up was developed to achieve multichannel sound field reproduction. In this paper, acoustic imaging with an 80-channel microphone array is applied to the objective evaluation, in terms of spatial sound accuracy, of sound field reproduction in the mock-up. Two imaging algorithms are tested, compared and discussed with respect to their ability to provide meaningful attributes for an objective evaluation and comparison of sound field reproduction performance of environmental source distributions. General conclusions about the applicability of acoustic imaging and tested algorithms for the spatial quality assessment of spatial reproduction systems are also provided. Copyright © (2013) by the Audio Engineering Society. | |||||
BibTeX:
@conference{Gauthier2013129, author = {Gauthier, P.-A. and Camier, C. and Padois, T. and Gauthier, O. and Pasco, Y. and Berry, A.}, title = {Objective evaluation of sound field and sound environment reproduction in aircraft mock-ups using acoustic imaging}, journal = {Proceedings of the AES International Conference}, year = {2013}, pages = {129-138}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897536493&partnerID=40&md5=c0945b144aa72acd8363adebc4e5f959} } |
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Gauthier, P.-A., Camier, C., Gauthier, O., Pasco, Y. and Berry, A. | Sound field reproduction of real flight recordings in cabin mock-up | 2013 | Proceedings of the AES International Conference, pp. 26-35 | conference | URL |
Abstract: Sound environment reproduction of various flight conditions in aircraft mock-ups is a valuable tool for the study, prediction, demonstration and jury testing of interior aircraft sound quality. To provide a faithful reproduced sound environment, time, frequency and spatial characteristics should be preserved. Physical sound field reproduction approaches for spatial sound reproduction are mandatory to immerse the listener body in the proper sound field so that localization cues are recreated. For sound field reproduction inside cabin mock-up, our approach relies on multichannel equalization using least-mean-square formulation. In this paper, a modified multichannel equalization procedure is proposed to simplify the selection of reproduction sources regularization. The paper presents objective evaluations of reproduced sound fields on the basis of real flight recordings using an 80-channel microphone array and 41 actuators in the cabin mock-up. Copyright © (2013) by the Audio Engineering Society. | |||||
BibTeX:
@conference{Gauthier201326, author = {Gauthier, P.-A. and Camier, C. and Gauthier, O. and Pasco, Y. and Berry, A.}, title = {Sound field reproduction of real flight recordings in cabin mock-up}, journal = {Proceedings of the AES International Conference}, year = {2013}, pages = {26-35}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897540921&partnerID=40&md5=c4a5e7a8f1bff535f8227d5e3163e96a} } |
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Gérard, A., Besombes, M., Berry, A., Masson, P. and Moreau, S. | Tonal noise control from centrifugal fans using flow control obstructions | 2013 | Noise Control Engineering Journal Vol. 61(4), pp. 381-388 |
article | DOI URL |
Abstract: Tonal noise originates from non-uniform flow that causes circumferentially varying blade forces and gives rise to a considerably larger radiated dipolar sound at the blade passage frequency (BPF) and its harmonics. The approach presented in this paper adapts a tonal noise control method previously developed for axial fans to centrifugal fans using obstructions in the flow to destructively interfere with the primary non-uniform flow arising from stator/rotor interaction. The flow control obstruction is located such that the secondary radiated noise is of equal magnitude but opposite in phase compared to the primary noise. Experiments were carried out for a centrifugal fan test bench to validate the method for controlling BPF tonal noise by carefully positioning obstructions in a duct in the upstream flow. © 2013 Institute of Noise Control Engineering. | |||||
BibTeX:
@article{Gérard2013381, author = {Gérard, A. and Besombes, M. and Berry, A. and Masson, P. and Moreau, S.}, title = {Tonal noise control from centrifugal fans using flow control obstructions}, journal = {Noise Control Engineering Journal}, year = {2013}, volume = {61}, number = {4}, pages = {381-388}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84886504289&doi=10.3397%2f1%2f3761032&partnerID=40&md5=7fa16e8f7046f105e83be9ff565d0b7c}, doi = {https://doi.org/10.3397/1/3761032} } |
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Gérard, A., Berry, A., Masson, P. and Moreau, S. | Use of a beat effect for the automatic positioning of flow obstructions to control tonal fan noise: Theory and experiments | 2013 | Journal of Sound and Vibration Vol. 332(19), pp. 4450-4460 |
article | DOI URL |
Abstract: Tonal noise generated by axial fans at the Blade Passage Frequency and its harmonics is a source of discomfort for low-speed fans used in many cooling and ventilation applications. The noise control approach presented here is based on the interference between the unsteady aerodynamic blade loads responsible for tonal noise generation and secondary aerodynamic loads generated in the rotor plane by fixed, carefully positioned, small obstructions in the upstream flow. Although not strictly active control, the magnitude and phase of the secondary tonal noise can be adjusted by varying the axial distance between the rotor and the obstruction, and the circumferential position of the obstruction, respectively. An optimal position of the obstruction generally exists, that minimizes the total noise at a given frequency. This paper establishes a practical method for automatic positioning of such control obstructions. In a first step, the method searches for the optimal axial distance between the rotor and the obstruction using a slowly rotating control obstruction. The modulation created by the rotation of the obstruction allows for the primary and secondary noises to be distinguished in the frequency response of the sound field. The steepest descent algorithm is used to find the optimal axial distance, for which the magnitudes of the primary and secondary tonal noise are equal at the error microphone. Then, the optimal angular position of the obstruction is obtained by slowly rotating the obstruction until minimal total noise is achieved. Finally, it is shown that at the optimal axial and angular position, the BPF tone, which produced the largest area in the loudness pattern, has been greatly reduced. © 2013 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Gérard20134450, author = {Gérard, A. and Berry, A. and Masson, P. and Moreau, S.}, title = {Use of a beat effect for the automatic positioning of flow obstructions to control tonal fan noise: Theory and experiments}, journal = {Journal of Sound and Vibration}, year = {2013}, volume = {332}, number = {19}, pages = {4450-4460}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879011899&doi=10.1016%2fj.jsv.2013.03.023&partnerID=40&md5=f458403204902e394ea8c88e76b230dc}, doi = {https://doi.org/10.1016/j.jsv.2013.03.023} } |
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Halkyard, R. and Masson, P. | Impact localisation in orthotropic plates using flexural wave intensity measurement | 2013 | Key Engineering Materials Vol. 569-570, pp. 718-725 |
article | DOI URL |
Abstract: In this paper, a method for the localisation and quantification of impacts on orthotropic plates, based on the measurement of the resulting vibrational energy flow, or structural intensity, is presented. The outputs of a compact array of bonded piezo-electric sensors are digitally filtered and combined to yield a local estimate of the instantaneous vibrational energy flow. In the case of transient vibration due to an impact, two or more such estimates can be used to localise the point of impact. The use of energy flow vectors for localisation requires a priori knowledge of the material properties, but may provide more direct access to position information than conventional techniques. Furthermore, the magnitude of the measured energy flow, when combined with knowledge of the impact location, can provide a quantitative measure of impact severity. The approach is based on Kirchhoff orthotropic plate theory, and is thus applicable to low frequencies, and utilises instantaneous estimates of the local wave field to allow the estimation of the various forces, moments and velocities that are required to calculate the vibrational energy flow. The theoretical background and principles of implementation of the approach are outlined, and the effects of sensor array design on systematic errors and sensitivity to measurement noise are discussed. Numerical simulations are used to assess the effectiveness of the technique and to determine its sensitivity to noise and other errors. These simulations suggest that the obtained energy flow estimates can be used for impact localisation. © (2013) Trans Tech Publications. | |||||
BibTeX:
@article{Halkyard2013718, author = {Halkyard, R.C. and Masson, P.}, title = {Impact localisation in orthotropic plates using flexural wave intensity measurement}, journal = {Key Engineering Materials}, year = {2013}, volume = {569-570}, pages = {718-725}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883696936&doi=10.4028%2fwww.scientific.net%2fKEM.569-570.718&partnerID=40&md5=9cdca863dfa21e582bacb072991b6758}, doi = {https://doi.org/10.4028/www.scientific.net/KEM.569-570.718} } |
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Lapointe, R., Berry, A., Camier, C., Blais, J.-F., Patenaude-Dufour, M., Gauthier, P.-A., Padois, T. and Provencher, J. | Aircraft noise source identification using a microphone array: Montreal-trudeau airport test campaign | 2013 | SAE Technical Papers Vol. 7 |
article | DOI URL |
Abstract: This paper summarizes the techniques used during a microphone array test campaign performed at Pierre-Elliott-Trudeau Airport in Montréal, Québec (Canada) during the summer of 2012. Emphasis is put on the actual measurement campaign as only a limited amount of analysis has been performed at this stage. An aircraft position tracking tool is presented along with the beamforming algorithms that were used. Over 500 aircraft were recorded during this test. A comparison of known tonal sources associated to a specific aircraft type is made between different airlines in order to evaluate the repeatability of the method. Copyright © 2013 SAE International. | |||||
BibTeX:
@article{Lapointe2013, author = {Lapointe, R. and Berry, A. and Camier, C. and Blais, J.-F. and Patenaude-Dufour, M. and Gauthier, P.-A. and Padois, T. and Provencher, J.}, title = {Aircraft noise source identification using a microphone array: Montreal-trudeau airport test campaign}, journal = {SAE Technical Papers}, year = {2013}, volume = {7}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84890321768&doi=10.4271%2f2013-01-2129&partnerID=40&md5=1f5fddcd32cf950d0cca0602464ba1fa}, doi = {https://doi.org/10.4271/2013-01-2129} } |
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Leclaire, P., Dupont, T. and Panneton, R. | Acoustics of porous materials with partially opened porosity | 2013 | Journal of the Acoustical Society of America Vol. 134(6), pp. 4630-4641 |
article | DOI URL |
Abstract: A theoretical and experimental study of the acoustic properties of porous materials containing dead-end (or partially opened) porosity was recently proposed by Dupont, Leclaire, Sicot, Gong, and Panneton [J. Appl. Phys. 110, 094903 (2011)]. The present article provides a description of partially opened porosity systems and their numerous potential applications in the general context of the study of porous materials, the classical models describing them, and the characterization techniques. It is shown that the dead-end pore effect can be treated independently and that the description of this effect can be associated with any acoustic model of porous media. Different theoretical developments describing the dead-end porosity effect are proposed. In particular, a model involving the average effective length of the dead-end pores is presented. It is also shown that if the dead-end effect can be treated separately, the transfer matrix method is particularly well suited for the description of single or multilayer systems with dead-end porosity. © 2013 Acoustical Society of America. | |||||
BibTeX:
@article{Leclaire20134630, author = {Leclaire, P. and Dupont, T. and Panneton, R.}, title = {Acoustics of porous materials with partially opened porosity}, journal = {Journal of the Acoustical Society of America}, year = {2013}, volume = {134}, number = {6}, pages = {4630-4641}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84890225804&doi=10.1121%2f1.4824836&partnerID=40&md5=3c1a809c5c991f39b64b739a71a64799}, doi = {https://doi.org/10.1121/1.4824836} } |
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Legault, J. and Atalla, N. | Erratum: Numerical and experimental investigation of the effect of structural links on the sound transmission of a lightweight double panel structure (Journal of Sound and Vibration (2009) 324 (712-732)) [BibTeX] |
2013 | Journal of Sound and Vibration Vol. 332(8), pp. 2119-2121 |
article | DOI URL |
BibTeX:
@article{Legault20132119, author = {Legault, J. and Atalla, N.}, title = {Erratum: Numerical and experimental investigation of the effect of structural links on the sound transmission of a lightweight double panel structure (Journal of Sound and Vibration (2009) 324 (712-732))}, journal = {Journal of Sound and Vibration}, year = {2013}, volume = {332}, number = {8}, pages = {2119-2121}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873414519&doi=10.1016%2fj.jsv.2012.12.004&partnerID=40&md5=3a6e45a84566168c72f59c7df6ff079a}, doi = {https://doi.org/10.1016/j.jsv.2012.12.004} } |
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Leleux, A., Micheau, P. and Castaings, M. | Long range detection of defects in composite plates using lamb waves generated and detected by ultrasonic phased array probes | 2013 | Journal of Nondestructive Evaluation Vol. 32(2), pp. 200-214 |
article | DOI URL |
Abstract: This article presents a technique for the generation and detection of Lamb waves guided along large plate-like structures made from various types of materials (metal, polymer, fibre-reinforced composite, etc.). A multi-element matrix ultrasonic probe is driven using the well-known phased array principle, for launching and detecting pure Lamb modes in/from specific directions along the plate, which are arbitrary for isotropic materials and limited to specific directions for anisotropic materials, e.g. principal directions or directions for which both phase and group velocities are collinear. The probe is gel-coupled to the tested specimen and allows quick inspection of large area from its fixed position, even of zones with limited access. The technique, which takes into account the frequency dispersive effects, is different than SHM-like (Structural Health Monitoring) inspection, since all transmitting or receiving elements are grouped together in a localized area defined by the active surface of the probe, and not permanently attached to the tested structure. The use of a multi-element probe, for long range Lamb waves-based inspection, is also distinctive from that usually performed, which consists of very local inspection of a material by steering the ultrasonic beam below and nearby the probe. A prototype is presented, as well as measurements of its performances in terms of modal selectivity and directivity. Finally the detection and localisation of a through-thickness hole in a large aluminium plate, of a delamination-like defect in a carbon epoxy composite plate and of an impact damage on a stiffened composite curved plate are shown. © 2013 Springer Science+Business Media New York. | |||||
BibTeX:
@article{Leleux2013200, author = {Leleux, A. and Micheau, P. and Castaings, M.}, title = {Long range detection of defects in composite plates using lamb waves generated and detected by ultrasonic phased array probes}, journal = {Journal of Nondestructive Evaluation}, year = {2013}, volume = {32}, number = {2}, pages = {200-214}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84882644217&doi=10.1007%2fs10921-013-0173-0&partnerID=40&md5=1b91a9dffed5e90e638b14065e289d3d}, doi = {https://doi.org/10.1007/s10921-013-0173-0} } |
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Lépine, J., Champoux, Y. and Drouet, J.-M. | Influence of test conditions on comfort ranking of road bicycle wheels | 2013 | Conference Proceedings of the Society for Experimental Mechanics Series Vol. 6, pp. 77-82 |
conference | DOI URL |
Abstract: In the past few years, the dynamic comfort of bicycles has become a hot topic in the cycling industry. To improve comfort, a wide variety of dynamic tests is used to characterize and compare bikes. Because these tests usually involve a cyclist, and since the tires have a non-linear effect on the system, test protocols are expected to have an impact on the dynamic characteristics and bicycle ranking. With the objective of establishing good practices when comparing wheel comfort, this paper presents the influence of several test parameters on the vibrations induced to the cyclist at the hands and buttocks. The influence of two excitation surfaces on bicycle dynamics is studied: a flat excitation surface and an irregular surface that locally deforms the tire. The type of excitation, such as white noise, impacts and typical road excitation, are also investigated. Results with regard to the effect of the cyclist's mass are also presented. The conclusion of this study shows that even if those parameters have a significant influence on the vibration levels transmitted to the cyclist, they do not affect the transmissibility ranking of two wheelsets. It should be noted however that the changes observed in the cyclist's posture and position on the bicycle can affect wheelset ranking. Great care is therefore advised in controlling the cyclist's posture and attitude on the bicycle during the tests. © The Society for Experimental Mechanics, Inc. 2013. | |||||
BibTeX:
@conference{Lépine201377, author = {Lépine, J. and Champoux, Y. and Drouet, J.-M.}, title = {Influence of test conditions on comfort ranking of road bicycle wheels}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2013}, volume = {6}, pages = {77-82}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889570649&doi=10.1007%2f978-1-4614-6546-1_7&partnerID=40&md5=7c90c6d31c50223453d21b245dfd8f9e}, doi = {https://doi.org/10.1007/978-1-4614-6546-1_7} } |
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Magne, S., Sanjosé, M., Moreau, S., Berry, A. and Gérard, A. | Tonal noise control of centrifugal fan using flow obstructions - experimental and numerical approaches | 2013 | 19th AIAA/CEAS Aeroacoustics Conference, pp. 42 | conference | URL |
Abstract: Placing a flow obstruction at the inlet of a fan is a cheap, yet efficient way to reduce the tonal noise. However, the optimization of this method is not straightforward since the aeroacoustic mechanisms responsible for the noise reduction have not yet been fully understood. As an attempt to highlight these mechanisms, an experimental and numerical study of the interaction between an obstruction and a centrifugal fan is presented. Four different types of obstructions are tested experimentally and their effect on the aerodynamic performance and the acoustic signature is characterized. A direct aeroacoustic simulation is then performed with a sinusoidal obstruction. The tonal noise reduction at the blade passing frequency is well captured, but the optimal angular position show some discrepancies with the experimental results. | |||||
BibTeX:
@conference{Magne201342, author = {Magne, S. and Sanjosé, M. and Moreau, S. and Berry, A. and Gérard, A.}, title = {Tonal noise control of centrifugal fan using flow obstructions - experimental and numerical approaches}, journal = {19th AIAA/CEAS Aeroacoustics Conference}, year = {2013}, pages = {42}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883732089&partnerID=40&md5=5a9e64b3424ae09cc91c3db20e7e79e6} } |
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Manning, J. and Panneton, R. | Acoustical model for Shoddy-based fiber sound absorbers | 2013 | Textile Research Journal Vol. 83(13), pp. 1356-1370 |
article | DOI URL |
Abstract: A simple equivalent fluid model is proposed to describe the acoustic behavior of post-consumer and post-industrial recycled fibers otherwise known as Shoddies. The model requires knowledge of the bulk density only, a parameter that is easily measured. Characterization testing was completed on nine Shoddy fiber constructions processed by one of three different methods: thermal bonding, resin bonding, and mechanical bonding. The parameters measured directly were bulk density, open porosity, tortuosity, static airflow resistivity, and normal incidence sound absorption. The materials' viscous and thermal characteristic lengths and static thermal permeability are determined using indirect acoustical techniques. Empirical relationships linking the material parameters to the bulk density are then substituted into several popular equivalent fluid models. The most accurate ‘simplified’ model is selected by comparing each model's ability to accurately predict the materials' acoustic behavior using normal incidence sound absorption to assess performance. The present work is of interest to sound engineers in predicting the acoustic performance of Shoddy-based absorbers. © 2013, SAGE Publications. All rights reserved. | |||||
BibTeX:
@article{Manning20131356, author = {Manning, J. and Panneton, R.}, title = {Acoustical model for Shoddy-based fiber sound absorbers}, journal = {Textile Research Journal}, year = {2013}, volume = {83}, number = {13}, pages = {1356-1370}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880681400&doi=10.1177%2f0040517512470196&partnerID=40&md5=3e52d649b8f74a5c4f72b8b206a56a70}, doi = {https://doi.org/10.1177/0040517512470196} } |
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Masson, P., Quaegebeur, N., Brunel, A. and Mrad, N. | Implementation of a novel imaging technique in an existing structural health monitoring system | 2013 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 8695 |
conference | DOI URL |
Abstract: In this paper, a novel imaging technique is assessed with a structural health monitoring (SHM) system based on a sparse array of piezoceramic sensors and actuators for in-plane inspection. The imaging approach used in this system is based on the Time-of-Flight (ToF), and the knowledge of the velocity of ultrasonic waves in the structure. While this technique assumes non-dispersive wave propagation, the proposed imaging technique exploits the dispersion of waves as it is based on the phase velocity. The signal measured at a given sensor is correlated with a theoretical prediction of a propagated burst in the structure and, combining the results for multiple sensors, an image of the reflectors in the structure is obtained. This paper presents the implementation of the novel imaging technique in an existing system, including considerations for physical access to the signals and their conditioning. The performance of the existing imaging approach is compared with the novel imaging technique proposed for two test cases. The first assessment is conducted on a simple aluminum plate where magnets are used to simulate a defect. Then, the assessment of the novel imaging techniques is conducted on riveted plates with simulated cracks of different lengths. Imaging results are presented for a number of damage detection scenarios on these structures. The novel imaging technique is shown to improve imaging localization, resolution and robustness, while allowing fast implementation. © 2013 SPIE. | |||||
BibTeX:
@conference{Masson2013, author = {Masson, P. and Quaegebeur, N. and Brunel, A. and Mrad, N.}, title = {Implementation of a novel imaging technique in an existing structural health monitoring system}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2013}, volume = {8695}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878576885&doi=10.1117%2f12.2009723&partnerID=40&md5=b7719d29148c2d4f8bd62e632de5ea39}, doi = {https://doi.org/10.1117/12.2009723} } |
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Mosanenzadeh, S., Doutres, O., Naguib, H., Park, C. and Atalla, N. | Modeling the acoustic absorption behaviour of polylactide open cell foams with bimodal structure for high acoustic absorption | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: Through this research, highly porous open cell foams were fabricated with Polylactide (PLA) and Polyethylene glycol (PEG) using compression molding combined with particulate leaching technique. Salt and water soluble polymer were used as the particulates. The pore size of the foam structure is controlled by the particulates size and higher interconnectivity is achieved by the co-continuous blending morphology of PLA matrix with water-soluble PEG. As a result of employing water soluble polymer into PLA foams, a bimodal cell structure was fabricated. Both PLA and PEG are fully bio-based polymers derived from renewable resources. Therefore, the resulting acoustic foams are benign and environmentally friendly. As a result of the secondary porous structure formed into cell walls by the water soluble polymer, the overall absorption of fabricated PLA foams was increased to above 90% while the average absorption of the foams remained unchanged. Fabricated foams were characterized for cellular, acoustic and mechanical properties. Open porosities as high as 88% was achieved through this study. Johnson-Champoux-Allard model was used to investigate the effect of bimodal structure on acoustic properties of PLA open cell foams. Foams fabricated through this study have the potential to replace the petrochemical based foams currently used in acoustic applications. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Mosanenzadeh2013, author = {Mosanenzadeh, S.G. and Doutres, O. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {Modeling the acoustic absorption behaviour of polylactide open cell foams with bimodal structure for high acoustic absorption}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878968815&doi=10.1121%2f1.4800955&partnerID=40&md5=725e54df0afc019941c59721d4ca3b58}, doi = {https://doi.org/10.1121/1.4800955} } |
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Mosanenzadeh, S., Naguib, H., Park, C. and Atalla, N. | Development, characterization, and modeling of environmentally friendly open-cell acoustic foams | 2013 | Polymer Engineering and Science Vol. 53(9), pp. 1979-1989 |
article | DOI URL |
Abstract: This study shows the development of new polymeric open-cell foams from polypropylene (PP) and polylactide (PLA) resins with a focus on sound absorption properties and modeling of these foams. The objective is to develop new environmentally friendly foams to replace the existing non-recyclable Polyurethane foams are currently used for sound insulation in industry. Through this research, open-cell foams of about 90% porosity were fabricated from PP and PLA. These resins were selected since PP is a recyclable thermoplastic polymer, and PLA is a bio-based thermoplastic polymer made from renewable resources. Polyurethane (PU) foam which is currently used for sound absorption and noise control in industry was compared to the fabricated PP and PLA foams. As the first attempt to fabricate environmentally friendly acoustic foams, the resulting foam structures show improved properties as compared to the existing materials. The average absorption of PP and PLA foams fabricated is in the range of 0.42-0.55 which is comparable or even higher than the average absorption of PU foam. To better understand the effect of structural and material properties on sound absorption and further improve the acoustic performance of bio-based foams, an analytical model based on Johnson-Champoux-Allard model was used to numerically simulate the acoustic performance of foams under study. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers Copyright © 2013 Society of Plastics Engineers. | |||||
BibTeX:
@article{Mosanenzadeh20131979, author = {Mosanenzadeh, S.G. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {Development, characterization, and modeling of environmentally friendly open-cell acoustic foams}, journal = {Polymer Engineering and Science}, year = {2013}, volume = {53}, number = {9}, pages = {1979-1989}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84882450462&doi=10.1002%2fpen.23443&partnerID=40&md5=c719dedcb016803a751e1d0f38b5b917}, doi = {https://doi.org/10.1002/pen.23443} } |
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Mulligan, K., Yang, C., Quaegebeur, N. and Masson, P. | A data-driven method for predicting structural degradation using a piezoceramic array | 2013 | International Journal of Prognostics and Health Management Vol. 4(2) |
article | URL |
Abstract: There is a growing use of carbon fiber reinforced polymers (CFRPs) in modern airframes with still a limited understanding of the in-service behavioral characteristics of these structures. Structural Health Monitoring (SHM) technologies that use surface-bonded piezoceramic (PZT) transducers to generate and measure guided waves within these structures have demonstrated promising damage detection and localization results and potential for data gathering in data-driven damage prognosis. This paper investigates the development of a data-driven SHM based damage prognosis system for estimating remaining useful life (RUL) of CFRP coupons following damage initiation. A robust and realistic laboratory data gathering methodology is introduced as a building block for evaluating the feasibility of data-driven damage prognosis for in-service aerospace structures. Data are gathered using a PZT-based SHM system. Using the gathered raw guided wave signals, a number of time and frequency domain features are first extracted which are derived from existing damage imaging and detection algorithms. Then, using various combinations of the feature sets as inputs to generic data mining algorithms, the paper presents estimates of the predicted RUL against actual damage diameter progression. | |||||
BibTeX:
@article{Mulligan2013, author = {Mulligan, K.R. and Yang, C. and Quaegebeur, N. and Masson, P.}, title = {A data-driven method for predicting structural degradation using a piezoceramic array}, journal = {International Journal of Prognostics and Health Management}, year = {2013}, volume = {4}, number = {2}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892389739&partnerID=40&md5=d2ca585786fabd5b2b157d0552eea2c4} } |
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Mulligan, K., Quaegebeur, N., Ostiguy, P.-C., Masson, P. and Létourneau, S. | Comparison of metrics to monitor and compensate for piezoceramic debonding in structural health monitoring | 2013 | Structural Health Monitoring Vol. 12(2), pp. 153-168 |
article | DOI URL |
Abstract: This article investigates metrics to assess and compensate for the degradation of the adhesive layer of surface-bonded piezoceramic transducers for structural health-monitoring applications. Capacitance, resonance frequency, and modal damping parameters are derived from admittance curves using a lumped parameter model to monitor the degradation of the transducer adhesive layer. A pitch-catch configuration is then used to discriminate the effect of bonding degradation on actuation and sensing. It is shown that below the first mechanical resonance frequency of the piezoceramic transducers, the degradation causes a decrease in the amplitude of the transmitted and received signals, while above resonance, in addition to a decrease in the amplitude of the transmitted and received signals, a linear phase shift is observed. A signal-correction factor is proposed to adjust signals based on adhesive degradation evaluated using the measured modal damping. The benefits of the signal-correction factor are demonstrated in the frequency domain for both the A0 and S0 modes. © The Author(s) 2012. | |||||
BibTeX:
@article{Mulligan2013153, author = {Mulligan, K.R. and Quaegebeur, N. and Ostiguy, P.-C. and Masson, P. and Létourneau, S.}, title = {Comparison of metrics to monitor and compensate for piezoceramic debonding in structural health monitoring}, journal = {Structural Health Monitoring}, year = {2013}, volume = {12}, number = {2}, pages = {153-168}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84875449960&doi=10.1177%2f1475921712467490&partnerID=40&md5=26a53e2f693f5c21d958dd4ff64caae9}, doi = {https://doi.org/10.1177/1475921712467490} } |
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Nadeau, M., Micheau, P., Robert, R., Avoine, O., Tissier, R., Germim, P. and Walti, H. | Control of rapid hypothermia induction by total liquid ventilation : Preliminary results | 2013 | Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, pp. 3757-3760 | conference | DOI URL |
Abstract: Mild therapeutic hypothermia (MTH) consists in cooling the body temperature of a patient to between 32 and 34 °C. This technique helps to preserve tissues and neurological functions in multi-organ failure by preventing ischemic injury. Total liquid ventilation (TLV) ensures gas exchange in the lungs with a liquid, typically perfluorocarbon (PFC). A liquid ventilator is responsible for ensuring cyclic renewal of tidal volume of oxygenated and temperature- controlled PFC. Hence, TLV using the lung as a heat exchanger and PFC as a heat carrier allows ultra fast cooling of the whole body which can help improve outcome after ischemic injuries. The present study was aimed to evaluate the control performance and safety of automated ultrarapid MTH induction by TLV. Experimentation was conducted using the Inolivent-5.0 liquid ventilator equipped with a PFC treatment unit that allows PFC cooling and heating from the flow of energy carrier water inside a double wall installed on an oxygenator. A water circulating bath is used to manage water temperature. A feedback controller was developed to modulate inspired PFC temperature and control body temperature. Such a controller is important since, with MTH induction, heart temperature should not reach 28 °C because of a high risk of fibrillation. The in vivo experimental protocol was conducted on a male newborn lamb of 4.7 kg which, after anesthetization, was submitted to conventional gas ventilation and instrumented with temperature sensors at the femoral artery, oesophagus, right ear drum and rectum. After stabilization, TLV was initiated with fast automated MTH induction to 33.5 °C until stabilization of all temperatures. MTH could be reached safely in 3 minutes at the femoral artery, in 3.6 minutes at the esophagus, in 7.7 minutes at the eardrum and in 15 minutes at the rectum. All temperatures were stable at 33.5 ± 0.5 °C within 15 minutes. The present results reveal that ultra-fast MTH induction by TLV with Inolivent-5.0 is safe for the heart while maintaining esophageal and arterial temperature over 32.6 °C. © 2013 IEEE. | |||||
BibTeX:
@conference{Nadeau20133757, author = {Nadeau, M. and Micheau, P. and Robert, R. and Avoine, O. and Tissier, R. and Germim, P.S. and Walti, H.}, title = {Control of rapid hypothermia induction by total liquid ventilation : Preliminary results}, journal = {Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS}, year = {2013}, pages = {3757-3760}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84886473768&doi=10.1109%2fEMBC.2013.6610361&partnerID=40&md5=47788aee49dc5efc7de0ba24fea70947}, doi = {https://doi.org/10.1109/EMBC.2013.6610361} } |
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Oddo, R., Gerard, A., Pearson, M., Amyotte, A., Masson, P., Sgard, F. and Berry, A. | Industrial fan noise control using flow obstructions | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: Fans are used in a lot of industrial processes and are sometimes a source of important noise for workers. We have focused on fans having a high tonal content, for which the Simple Silence technology can be applied, i.e. tonal fan noise control using obstructions in the flow. Evaporator fan noise control in a cold storage room, based on previous work on fan noise control in free field is first presented. Then, in-duct gold mine underground air-extractor fan noise control is presented, an original analytical model is derived for noise generation and propagation inside the duct, and preliminary experimental results are provided. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Oddo2013, author = {Oddo, R. and Gerard, A. and Pearson, M. and Amyotte, A. and Masson, P. and Sgard, F. and Berry, A.}, title = {Industrial fan noise control using flow obstructions}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878969236&doi=10.1121%2f1.4799638&partnerID=40&md5=46793a84d42d0dc838bc129b6b8b62d5}, doi = {https://doi.org/10.1121/1.4799638} } |
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Ouisse, M., Doutres, O., Atalla, N., Ichchou, M. and Begg, D. | Investigations on the sensitivity of the relationships between sound absorption characteristics and microstructure related parameters for polyurethane foams | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: Straightforward semi-phenomenological models have been developed for highly porous polyurethane foams to predict the macroscopic non-acoustic parameters involved in the classical Johnson-Champoux-Allard model (i.e., porosity, airflow resistivity?) from microstructure properties (i.e, strut length, strut thickness and reticulation rate). These microstructure properties are measured using sophisticated optical methods (i.e., optical microscope, SEM) and a large variability can be observed due to great complexity of the 3D microstructure; variability which also depends on the precision of the measurement device. This work investigates how the variability associated with the model inputs affects the model outputs (i.e., non-acoustic parameters, surface impedance and sound absorption coefficient). The sensitivity analysis is based on the Fourier Amplitude Sensitivity Test (FAST). It helps quantify the correlation between the input parameters and identify the parameters contributing the most to output variability, thus requiring precise measurement. This study illustrates the preponderant impact of the reticulation rate (i.e, open pore content) on acoustic performances and guides the user on the required optical measurement device. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Ouisse2013, author = {Ouisse, M. and Doutres, O. and Atalla, N. and Ichchou, M. and Begg, D.}, title = {Investigations on the sensitivity of the relationships between sound absorption characteristics and microstructure related parameters for polyurethane foams}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878973469&doi=10.1121%2f1.4799699&partnerID=40&md5=57c87d732e267ccdaf2e363eb2240063}, doi = {https://doi.org/10.1121/1.4799699} } |
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Padois, T., Berry, A., Gauthier, P.-A. and Joshi, N. | Beamforming matrix regularization and inverse problem for sound source localization: Application to aero-engine noise | 2013 | 19th AIAA/CEAS Aeroacoustics Conference, pp. 202 | conference | URL |
Abstract: Phased-microphone arrays associated with beamforming have become a standard technique to localize aeroacoustic sources. The limitations of beamforming have been overcome thanks to deconvolution technique (DAMAS or CLEAN-SC) or iterative process (L1-GIB). However, the computational cost of these methods can be large or assumptions on the source coherence have to be done. In this paper we present a technique based on inverse methods initially developed for sound field extrapolation. The aim is to use a beamforming regularization matrix to penalize the non-signal region in the inverse problem. First, this Hybrid Method is applied to laboratory experiments to demonstrate its effectiveness. Then noise data of an aero-engine measured over a half circular, far-field microphone array are used. The source maps obtained show that the Hybrid Method provides better spatial resolution than beamforming, similar to Clean-SC and results in less iterations of DAMAS. | |||||
BibTeX:
@conference{Padois2013202, author = {Padois, T. and Berry, A. and Gauthier, P.-A. and Joshi, N.}, title = {Beamforming matrix regularization and inverse problem for sound source localization: Application to aero-engine noise}, journal = {19th AIAA/CEAS Aeroacoustics Conference}, year = {2013}, pages = {202}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883681458&partnerID=40&md5=824629f34e56c12fd5e52bea3b4513c1} } |
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Padois, T., Robin, O. and Berry, A. | 3D Source localization in a closed wind-tunnel using microphone arrays | 2013 | 19th AIAA/CEAS Aeroacoustics Conference, pp. 203 | conference | URL |
Abstract: The detection of aeroacoustic sources in closed or open wind-tunnels usually involves microphone arrays. In this case, the source are searched in a planar two-dimensional grid. Recently, the potential of beamforming with a three-dimensional grid has been studied but with a two-dimensional planar array. In this paper, we apply sound source localization techniques to a three-dimensional array. First, a numerical solver is used to simulate the acoustic propagation to the microphone arrays in order to validate the source localization methods. The results show that the source position is localized accurately. An experiment in a closed wind-tunnel is presented. We use four microphone arrays installed on the sides of a wind-tunnel. Each microphone array has 48 microphones. Two types of acoustic sources are used. The first one is a monopolar sound source with known amplitude and position. Then a cylinder is mounted across the flow to generate dipolar radiation patterns. | |||||
BibTeX:
@conference{Padois2013203, author = {Padois, T. and Robin, O. and Berry, A.}, title = {3D Source localization in a closed wind-tunnel using microphone arrays}, journal = {19th AIAA/CEAS Aeroacoustics Conference}, year = {2013}, pages = {203}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883711656&partnerID=40&md5=a029aac819e75912c0785c8aad74f031} } |
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Quaegebeur, N., Masson, P., Beaudet, N. and Sarret, P. | Pressure mapping system based on guided waves reflection | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: In this paper, guided wave interaction is used to develop a pressure mapping system for medical and touch-screen applications. The principle is based on interaction of guided waves in the presence of an added local mass and in the presence of a local pressure. For this purpose, piezoceramics are used for injecting guided waves into a thin structure and to measure the reflected waves due to the presence of an added mass or pressure. SHM imaging algorithms, based on Time-of-Flight or correlation, are implemented in order to obtain cartography of the reflections and deduce the presence, localization and intensity of local contact spots. Analytical models are first derived to assess the critical parameters in order to maximize the reflection of guided waves (first order modes A0 and S0). Validation on a 0.5 mm thick plane glass plate prototype is addressed using 1 actuator and 2 sensors. It is observed that imaging of single pressure spot can be achieved using both A0 and S0 mode around 300 kHz with a resolution of 0.5 mm. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Quaegebeur2013, author = {Quaegebeur, N. and Masson, P. and Beaudet, N. and Sarret, P.}, title = {Pressure mapping system based on guided waves reflection}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878963814&doi=10.1121%2f1.4799944&partnerID=40&md5=e7278b2d65dbeb234d2f4a48c984cb61}, doi = {https://doi.org/10.1121/1.4799944} } |
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Quaegebeur, N., Masson, P., Brault, L.-P., Beaudet, N. and Sarret, P. | Pressure mapping system based on guided waves reflection | 2013 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 8695 |
conference | DOI URL |
Abstract: In this paper, a guided wave-based pressure mapping system is presented for medical and touch-screen applications. Piezoceramics are used as actuators and to measure the reflected waves due to an added mass or local pressure, responsible for a change of local surface impedance. SHM imaging algorithms are implemented in order to obtain cartography of the reflections and deduce the presence, localization and intensity of pressure spots. Analytical and numerical models are validated on an aluminum plate prototype instrumented using 1 actuator and 2 sensors. It is observed that imaging of single or multiple pressure spots is achieved using both A0 and S0 modes around 300 kHz with a resolution of 0.5 mm. © 2013 SPIE. | |||||
BibTeX:
@conference{Quaegebeur2013, author = {Quaegebeur, N. and Masson, P. and Brault, L.-P. and Beaudet, N. and Sarret, P.}, title = {Pressure mapping system based on guided waves reflection}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2013}, volume = {8695}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878523641&doi=10.1117%2f12.2008949&partnerID=40&md5=abaff8f3bb637431fdd1efbc312b50f7}, doi = {https://doi.org/10.1117/12.2008949} } |
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Quaegebeur, N., Ostiguy, P.-C. and Masson, P. | Correlation-based imaging algorithm for bolt loosening monitoring on realistic aerospace structure | 2013 | Structural Health Monitoring 2013: A Roadmap to Intelligent Structures - Proceedings of the 9th International Workshop on Structural Health Monitoring, IWSHM 2013 Vol. 2, pp. 1936-1943 |
conference | URL |
Abstract: In the present study, a correlation-based imaging technique called « Excitelet » is proposed to monitor bolt loosening on an aluminum lap-joint, representative of an aircraft component. The principle is based on guided wave generation and sensing using a compact micro-machined piezoceramic array and measurement of reflections induced by potential damage. The method uses a propagation model to correlate measured signals with a bank of signals and imaging is performed using a round-robin procedure (Full-Matrix Capture). This methods allows taking into account the transducer dynamics and finite dimensions, multi-modal and dispersive characteristics of the material and complex interaction between guided wave and damage. Experimental validation has been realized on an aluminum lap-joint instrumented with a compact linear piezoceramic array of 8 circular elements of 3 mm diameter each. The imaging algorithm is applied to detect the partial and complete loosening of one of the bolts. Imaging results obtained using both A0 and S0 modes at 300 kHz are presented for each loosening condition. It is demonstrated that variations in the bolt torque can be accurately detected, while the correlation level indicates the level of reflected energy, related to the loosening. An accuracy of approximately 5 mm on damage location estimation can be achieved, demonstrating the possibilities of the correlation-based imaging technique for damage monitoring of complex aerospace structures. | |||||
BibTeX:
@conference{Quaegebeur20131936, author = {Quaegebeur, N. and Ostiguy, P.-C. and Masson, P.}, title = {Correlation-based imaging algorithm for bolt loosening monitoring on realistic aerospace structure}, journal = {Structural Health Monitoring 2013: A Roadmap to Intelligent Structures - Proceedings of the 9th International Workshop on Structural Health Monitoring, IWSHM 2013}, year = {2013}, volume = {2}, pages = {1936-1943}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945190517&partnerID=40&md5=5b248c30c74d3cdd5409df0ba164c9ad} } |
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Robin, O., Berry, A., Moreau, S. and Campeau, S. | Experimental reproduction of random pressure fields for vibroacoustic testing of plane panels | 2013 | 19th AIAA/CEAS Aeroacoustics Conference, pp. 26 | conference | URL |
Abstract: The feasability of the experimental reproduction of random pressure fields on a plane panel and corresponding induced vibrations is studied. The random pressure fields to be reproduced, a Diffuse Acoustic Field (DAF) and a Turbulent Boundary Layer (TBL), are described using their Cross-Spectral Densities (CSD). We propose an open-loop reproduction strategy that uses the synthetic array concept, for which a small array element is moved to create a large array by post-processing. Three possible approaches are suggested to define the complex amplitudes to be imposed at the post-processing step to all the virtual reproduction sources distributed on a virtual plane, the synthetic array, facing the panel to be tested. With a setup using a single acoustic monopole, a scanning laser vibrometer and a baffled simply supported aluminum panel, we obtain experimental vibroacoustic indicators such as the Transmission Loss (TL) for DAF, subsonic and supersonic TBL excitations. The assets or weaknesses inherent to each method are discussed, in terms of their aptitudes for reproducing the target pressure field for a given array geometry. The experimental TL results are compared to simulation results obtained using a commercial software. Most of the comparisons show that the three approaches are suitable for DAF and TBL wall pressure fluctuations reproduction, and thus should open perspectives for the experimental vibroacoustic testing of fuselage panels. | |||||
BibTeX:
@conference{Robin201326, author = {Robin, O. and Berry, A. and Moreau, S. and Campeau, S.}, title = {Experimental reproduction of random pressure fields for vibroacoustic testing of plane panels}, journal = {19th AIAA/CEAS Aeroacoustics Conference}, year = {2013}, pages = {26}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883732619&partnerID=40&md5=a41b1ebe4ad6e70835a7aedab0017dc0} } |
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Robin, O., Berry, A. and Moreau, S. | Reproduction of random pressure fields based on planar nearfield acoustic holography | 2013 | Journal of the Acoustical Society of America Vol. 133(6), pp. 3885-3899 |
article | DOI URL |
Abstract: This article discusses an open-loop approach based on planar nearfield acoustic holography (P-NAH) for the reproduction of random pressure fields, mainly intended for the measurement of vibroacoustic properties of plane panels. The main application is the simulation of turbulent boundary layer excitation in a laboratory environment, as an alternative to in-flight or wind tunnel experiments. The problem under study is the synthesis of random pressure distributions on a plane reproduction surface using acoustic monopoles distributed on a plane source surface facing the reproduction surface. The problem of reproducing a pressure distribution on a plane surface is addressed using the theoretical framework of P-NAH, which is extended to random pressure fields with corresponding imposed cross-spectral density functions. Results of numerical simulations are presented for the reproduction of a diffuse acoustic field, and a subsonic and supersonic turbulent boundary layer. The influence on the reproduction accuracy of the respective sizes of the two planes, their separation and the reproduction source separation are studied. The reproduction approach shows to be effective for the reproduction of diffuse acoustic field and turbulent boundary layer, but with different requirements in terms of plane separation and reproduction sources separation. In the specific case of subsonic turbulent boundary layer and associated sub-wavelength correlation scales reproduction, possible improvements of the method are suggested. © 2013 Acoustical Society of America. | |||||
BibTeX:
@article{Robin20133885, author = {Robin, O. and Berry, A. and Moreau, S.}, title = {Reproduction of random pressure fields based on planar nearfield acoustic holography}, journal = {Journal of the Acoustical Society of America}, year = {2013}, volume = {133}, number = {6}, pages = {3885-3899}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878900309&doi=10.1121%2f1.4802898&partnerID=40&md5=7b4be21b3bf945c6179a331bdfdec3e6}, doi = {https://doi.org/10.1121/1.4802898} } |
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Robin, O., Moreau, S., Padois, T. and Berry, A. | Measurement of the wavenumber-frequency spectrum of wall pressure fluctuations: Spiral-shaped rotative arrays with pinhole-mounted quarter inch microphones | 2013 | 19th AIAA/CEAS Aeroacoustics Conference, pp. 56 | conference | URL |
Abstract: This paper concerns the direct measurement of wavenumber-frequency spectra beneath a two-dimensional Turbulent Boundary Layer. The main contribution of this work is the proposed setup that should help achieving a compromise between a small sensor diameter (to avoid spatial averaging) and small sensor spacing (to gain high spatial resolution). The effect of different pinhole sizes on quarter inch microphones is first studied using an acoustical coupler to perform relative calibrations. Single-point measurements of wall pressure fluctuations in a wind-tunnel confirm that a 0.5 mm pinhole quarter inch microphone correctly captures wall pressure statistics up to a frequency of 5 kHz. Under the assumption of stationnary pressure fields, it is then suggested how rotative Archimedean spirals mainly composed of pinhole microphones can provide a uniform coverage of pressure measurements on a disc, or high resolution measurements in selected directions. Using 57 of these pinhole pressure sensors, a probe microphone as a central sensor reference and 3 Knowles pressure sensor, one of the suggested designs of spiral-shaped rotative arrays was instrumented. Measurements have been performed at low Mach numbers (M < 0:1) in a closed-loop wind-tunnel, with the array flush mounted on a side of the wind tunnel. The TBL is characterized with velocity measurements, and 2D wavenumber spectra of the wall pressure fluctuations are obtained which reveal the convective peak at low frequencies. Even preliminary and still contaminated by a strong background noise, these first results indicate that the experimental setup behaves as expected but needs additional refinements. The next steps of this on-going work are finally detailed. | |||||
BibTeX:
@conference{Robin201356, author = {Robin, O. and Moreau, S. and Padois, T. and Berry, A.}, title = {Measurement of the wavenumber-frequency spectrum of wall pressure fluctuations: Spiral-shaped rotative arrays with pinhole-mounted quarter inch microphones}, journal = {19th AIAA/CEAS Aeroacoustics Conference}, year = {2013}, pages = {56}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883734380&partnerID=40&md5=e85ebdbe11d73bd92d810eba0e43c5cf} } |
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Rzig, I., Atalla, N. and Mejdi, A. | Numerical prediction of the vibroacoustic of sandwich panels with add-on damping | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: This paper discusses the numerical modeling of the vibroacoustic response of sandwich panels with add-on damping, under two types of excitations: Point load, and acoustic excitation, diffuse acoustic field. The studied damping is of the form of a viscolaetsic layer located within the panel. A modal synthesis approach is used for the calculation of the structural response and the Rayleigh's integral is used for the acoustic response (the panel is assumed flat and baffled). Since the panel has a viscoelastic core, a methodology is presented to handle efficiently the modeling of the frequency depended properties of the viscoelastic layer. A direct frequency response is used to validate the proposed approach. Next, a parameters study on the effect of the viscoelastic layer location is presented, In particular, three locations are compared: within the Honeycomb core, within the skins and added to the skin with a constraining layer. The effects of the excitation type on the vibration and acoustic response are also discussed. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Rzig2013, author = {Rzig, I. and Atalla, N. and Mejdi, A.}, title = {Numerical prediction of the vibroacoustic of sandwich panels with add-on damping}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878956267&doi=10.1121%2f1.4801038&partnerID=40&md5=0931c79d3d6da4c9a33dd0d3f8de9d93}, doi = {https://doi.org/10.1121/1.4801038} } |
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Sgard, F., Atalla, N., Gholami, M. and Nelisse, H. | Tunneling effect on the sound transmission loss of a flat structure coupled with a porous material | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: It is well known that when measuring Sound Transmission Loss (STL) in a laboratory, among all test conditions, the location of a specimen in an aperture affects the results, due to the tunneling effect. Previous studies have considered this effect for flat single panels and double walls but the case of a panel with attached sound package seems to have received very little attention. This paper deals with the application of a modal approach to study the STL of a rectangular plate coupled with a porous material located inside a tunnel. The sound absorbing material is supposed to be either described by a modal approach or a transfer matrix calculated using a Transfer Matrix Method which relates interstitial pressure and total normal stress on both sides of the material. The model is validated by comparison with Finite Element/Boundary Element computations. Numerical results are shown to illustrate the validity of the proposed full modal and hybrid modal-TMM methodologies and their use to investigate the niche effect in presence of a sound absorbing material. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Sgard2013, author = {Sgard, F.C. and Atalla, N. and Gholami, M. and Nelisse, H.}, title = {Tunneling effect on the sound transmission loss of a flat structure coupled with a porous material}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878965749&doi=10.1121%2f1.4798806&partnerID=40&md5=7d26b360a7f938ec06e548acf728296c}, doi = {https://doi.org/10.1121/1.4798806} } |
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Vandamme, J., Robert, R., Micheau, P., Weil, F., Germin, P.-S., Avoine, O. and Praud, J.-P. | Alveolar pressure estimation in total liquid ventilation during pauses impeded by tube resonance | 2013 | MeMeA 2013 - IEEE International Symposium on Medical Measurements and Applications, Proceedings, pp. 191-195 | conference | DOI URL |
Abstract: Total liquid ventilation is an innovative experimental method of mechanical assisted ventilation in which lungs are totally filled and then ventilated with a tidal volume of perfluorochemical liquid (PFC) by using a dedicated liquid ventilator. The positive end-inspiratory and end-expiratory pressures (PEIP and PEEP) are static pressure measurements that are critic to the safe and efficient control of the ventilation. However, their measurement is impeded by large oscillations of pressure caused by the propagation of pressure waves along the flexible tubes carrying the PFC to the patient. The aim of this paper is to describe a method to accurately estimate the PEEP and the PEIP from noisy data hindered by flexible tubing resonance during short respiratory pauses. The method developped makes use of the least squares technique to estimate the steady state pressure. Preliminary in vivo validation of the algorithm shows that the method gives accurate estimations with respiratory pauses as short as 0.3 second. © 2013 IEEE. | |||||
BibTeX:
@conference{Vandamme2013191, author = {Vandamme, J. and Robert, R. and Micheau, P. and Weil, F. and Germin, P.-S. and Avoine, O. and Praud, J.-P.}, title = {Alveolar pressure estimation in total liquid ventilation during pauses impeded by tube resonance}, journal = {MeMeA 2013 - IEEE International Symposium on Medical Measurements and Applications, Proceedings}, year = {2013}, pages = {191-195}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881332824&doi=10.1109%2fMeMeA.2013.6549734&partnerID=40&md5=7cd44e510bb3202acae5e71dfa1da023}, doi = {https://doi.org/10.1109/MeMeA.2013.6549734} } |
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Verdière, K., Panneton, R., Elkoun, S., Dupont, T. and Leclaire, P. | Prediction of acoustic properties of parallel assemblies by means of transfer matrix method | 2013 | Proceedings of Meetings on Acoustics Vol. 19 |
conference | DOI URL |
Abstract: The Transfer Matrix Method (TMM) is used conventionally to predict the acoustic properties of laterally infinite homogeneous layers assembled in series to form a multilayer. In this work, a parallel assembly process of transfer matrices is used to model heterogeneous materials such as patchworks, acoustic mosaics, or a collection of acoustic elements in parallel. In this method, it is assumed that each parallel element can be modeled by a 2×2 transfer matrix, and no diffusion exists between elements. The method is validated by comparison with finite element method (FEM). Then, an overview of the possibilities, such as the combination of series and parallel matrices, the sound absorption coefficient and the transmission loss of a parallel array of resonators or three-dimensional geometries is presented and discussed. © 2013 Acoustical Society of America. | |||||
BibTeX:
@conference{Verdière2013, author = {Verdière, K. and Panneton, R. and Elkoun, S. and Dupont, T. and Leclaire, P.}, title = {Prediction of acoustic properties of parallel assemblies by means of transfer matrix method}, journal = {Proceedings of Meetings on Acoustics}, year = {2013}, volume = {19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878961483&doi=10.1121%2f1.4799562&partnerID=40&md5=c14804af1c0b0f2af745ab74713380e3}, doi = {https://doi.org/10.1121/1.4799562} } |
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Verdière, K., Panneton, R., Elkoun, S., Dupont, T. and Leclaire, P. | Transfer matrix method applied to the parallel assembly of sound absorbing materials | 2013 | Journal of the Acoustical Society of America Vol. 134(6), pp. 4648-4658 |
article | DOI URL |
Abstract: The transfer matrix method (TMM) is used conventionally to predict the acoustic properties of laterally infinite homogeneous layers assembled in series to form a multilayer. In this work, a parallel assembly process of transfer matrices is used to model heterogeneous materials such as patchworks, acoustic mosaics, or a collection of acoustic elements in parallel. In this method, it is assumed that each parallel element can be modeled by a 2 × 2 transfer matrix, and no diffusion exists between elements. The resulting transfer matrix of the parallel assembly is also a 2 × 2 matrix that can be assembled in series with the classical TMM. The method is validated by comparison with finite element (FE) simulations and acoustical tube measurements on different parallel/series configurations at normal and oblique incidence. The comparisons are in terms of sound absorption coefficient and transmission loss on experimental and simulated data and published data, notably published data on a parallel array of resonators. From these comparisons, the limitations of the method are discussed. Finally, applications to three-dimensional geometries are studied, where the geometries are discretized as in a FE concept. Compared to FE simulations, the extended TMM yields similar results with a trivial computation time. © 2013 Acoustical Society of America. | |||||
BibTeX:
@article{Verdière20134648, author = {Verdière, K. and Panneton, R. and Elkoun, S. and Dupont, T. and Leclaire, P.}, title = {Transfer matrix method applied to the parallel assembly of sound absorbing materials}, journal = {Journal of the Acoustical Society of America}, year = {2013}, volume = {134}, number = {6}, pages = {4648-4658}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84890161306&doi=10.1121%2f1.4824839&partnerID=40&md5=c6d2e3cc12ae6c17d77c2cfa5b7f7f8a}, doi = {https://doi.org/10.1121/1.4824839} } |
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Verron, C., Gauthier, P.-A., Langlois, J. and Guastavino, C. | Spectral and spatial multichannel analysis/synthesis of interior aircraft sounds | 2013 | IEEE Transactions on Audio, Speech and Language Processing Vol. 21(7), pp. 1317-1329 |
article | DOI URL |
Abstract: A method for spectral and spatial multichannel analysis/synthesis of interior aircraft sounds is presented. We propose two extensions of the classical sinusoids+noise model, adapted to multichannel stationary sounds. First, a spectral estimator is described, using average information across channels for spectral peak detection. Second, the residual modeling is extended to integrate two interchannel spatial cues (i.e., coherence and phase difference). This approach allows real-time synthesis and control of sounds spectral and spatial characteristics. It finds applications for multichannel aircraft sound reproduction, and more generally for musical and environmental sound synthesis. The ability of the model to reproduce multichannel aircraft sounds is assessed by a numerical simulation. © 2006-2012 IEEE. | |||||
BibTeX:
@article{Verron20131317, author = {Verron, C. and Gauthier, P.-A. and Langlois, J. and Guastavino, C.}, title = {Spectral and spatial multichannel analysis/synthesis of interior aircraft sounds}, journal = {IEEE Transactions on Audio, Speech and Language Processing}, year = {2013}, volume = {21}, number = {7}, pages = {1317-1329}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84875678069&doi=10.1109%2fTASL.2013.2248712&partnerID=40&md5=e8f078adeecf508c7c4b8ce3ec9a1a1c}, doi = {https://doi.org/10.1109/TASL.2013.2248712} } |
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Beaulieu, A., Bosse, D., Micheau, P., Avoine, O., Praud, J.-P. and Walti, H. | Measurement of fractional order model parameters of respiratory mechanical impedance in total liquid ventilation | 2012 | IEEE Transactions on Biomedical Engineering Vol. 59(2), pp. 323-331 |
article | DOI URL |
Abstract: This study presents a methodology for applying the forced-oscillation technique in total liquid ventilation. It mainly consists of applying sinusoidal volumetric excitation to the respiratory system, and determining the transfer function between the delivered flow rate and resulting airway pressure. The investigated frequency range was in 0.05, 4 Hz at a constant flow amplitude of 7.5 mL/s. The five parameters of a fractional order lung model, the existing 5-parameter constant-phase model, were identified based on measured impedance spectra. The identification method was validated in silico on computer-generated datasets and the overall process was validated in vitro on a simplified single-compartment mechanical lung model. In vivo data on ten newborn lambs suggested the appropriateness of a fractional-order compliance term to the mechanical impedance to describe the low-frequency behavior of the lung, but did not demonstrate the relevance of a fractional-order inertance term. Typical respiratory system frequency response is presented together with statistical data of the measured in vivo impedance model parameters. This information will be useful for both the design of a robust pressure controller for total liquid ventilators and the monitoring of the patients respiratory parameters during total liquid ventilation treatment. © 2006 IEEE. | |||||
BibTeX:
@article{Beaulieu2012323, author = {Beaulieu, A. and Bosse, D. and Micheau, P. and Avoine, O. and Praud, J.-P. and Walti, H.}, title = {Measurement of fractional order model parameters of respiratory mechanical impedance in total liquid ventilation}, journal = {IEEE Transactions on Biomedical Engineering}, year = {2012}, volume = {59}, number = {2}, pages = {323-331}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856173173&doi=10.1109%2fTBME.2011.2169257&partnerID=40&md5=77b7af34a3707ba6c6c01c56b5dca538}, doi = {https://doi.org/10.1109/TBME.2011.2169257} } |
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Belgacem, W., Masson, P. and Berry, A. | Active structural control on a car for cancellation of road noise disturbance | 2012 | 41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012 Vol. 1, pp. 30-46 |
conference | URL |
Abstract: An active structural control strategy is applied to the structure-borne road noise trans- mission paths on a car in the laboratory. A methodology is first presented for the real- ization of a vibro-acoustic model of the car using measured primary and secondary Fre- quency Response Functions (FRFs). Primary FRFs are characterized between the ex- citation signal at each wheel and each suspension/chassis linkages and secondary FRFs are characterized between the excitation on different locations at each suspension and each suspension/chassis linkages. Vibro-acoustic FRFs are also measured between the excitation (primary and secondary) and the acoustic pressure inside the car cabin. An experimental model of the car is used to simulate the configuration of the active con- trol system, using the primary FRFs and secondary FRFs. A genetic algorithm is then used to optimize the configuration of the control actuators. Optimal control results sim- ulate the noise reduction achieved by the approach in the cabin using candidate cost functions. A prototype of the active control was then implemented on the car and mea- surements were performed in order to assess the performance of the control approach. More than 10 dB attenuation on acoustic field inside the car was obtained at some fre- quencies. Finally, road excitation was used to simulate the active control performance on real conditions (car rolling at 50 km/h). Optimal control results show more than 17 dB(A) global attenuation inside the cabin between 20 Hz and 500 Hz. | |||||
BibTeX:
@conference{Belgacem201230, author = {Belgacem, W. and Masson, P. and Berry, A.}, title = {Active structural control on a car for cancellation of road noise disturbance}, journal = {41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012}, year = {2012}, volume = {1}, pages = {30-46}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883562152&partnerID=40&md5=ecc2ee33ef4a047cf65d7c61c8ec0817} } |
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Belgacem, W., Berry, A. and Masson, P. | Active vibration control on a quarter-car for cancellation of road noise disturbance | 2012 | Journal of Sound and Vibration Vol. 331(14), pp. 3240-3254 |
article | DOI URL |
Abstract: In this paper, a methodology is presented for the cancellation of road noise, from the analysis of vibration transmission paths for an automotive suspension to the design of an active control system using inertial actuators on a suspension to reduce the vibrations transmitted to the chassis. First, experiments were conducted on a Chevrolet Epica LS automobile on a concrete test track to measure accelerations induced on the suspension by the road. These measurements were combined with experimental Frequency Response Functions (FRFs) measured on a quarter-car test bench to reconstruct an equivalent three dimensional force applied on the wheel hub. Second, FRFs measured on the test bench between the three-dimensional driving force and forces at each suspension/chassis linkage were used to characterize the different transmission paths of vibration energy to the chassis. Third, an experimental model of the suspension was constructed to simulate the configuration of the active control system, using the primary (disturbance) FRFs and secondary (control) FRFs also measured on the test bench. This model was used to optimize the configuration of the control actuators and to evaluate the required forces. Finally, a prototype of an active suspension was implemented and measurements were performed in order to assess the performance of the control approach. A 4.6 dB attenuation on transmitted forces was obtained in the 50-250 Hz range. © 2012 Elsevier Ltd. | |||||
BibTeX:
@article{Belgacem20123240, author = {Belgacem, W. and Berry, A. and Masson, P.}, title = {Active vibration control on a quarter-car for cancellation of road noise disturbance}, journal = {Journal of Sound and Vibration}, year = {2012}, volume = {331}, number = {14}, pages = {3240-3254}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859780728&doi=10.1016%2fj.jsv.2012.02.030&partnerID=40&md5=91783cafe26163633249c1f327fccefd}, doi = {https://doi.org/10.1016/j.jsv.2012.02.030} } |
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Berry, A., Dia, R. and Robin, O. | A wave field synthesis approach to reproduction of spatially correlated sound fields | 2012 | Journal of the Acoustical Society of America Vol. 131(2), pp. 1226-1239 |
article | DOI URL |
Abstract: This article discusses an open-loop wave field synthesis (WFS) approach for the reproduction of spatially correlated sound fields. The main application concerns laboratory reproduction of turbulent boundary layer wall pressure on aircraft fuselages and measurement of their sound transmission loss. The problem configuration involves reconstruction of random sound pressure distributions on a planar reproduction surface using a planar array of reproduction monopoles parallel to the reproduction plane. In this paper, the WFS formulation is extended to sound fields with imposed time and spatial correlation properties (or equivalently imposed cross-spectral density in the frequency and wave number domains). Numerical examples are presented for the reproduction of a propagating plane wave, diffuse acoustic field and wall pressure in subsonic or supersonic turbulent boundary layers. The reproduction accuracy is examined in terms of the size of the source plane and reproduction plane, their separation, and the number of reproduction sources required per acoustic wavelength. While the reproduction approach cannot reconstruct sub-wavelength correlation scales of subsonic turbulent boundary layers, it effectively reconstructs correlation scales larger than the acoustic wavelength, making it appropriate for diffuse acoustic field and supersonic turbulent layers. © 2012 Acoustical Society of America. | |||||
BibTeX:
@article{Berry20121226, author = {Berry, A. and Dia, R. and Robin, O.}, title = {A wave field synthesis approach to reproduction of spatially correlated sound fields}, journal = {Journal of the Acoustical Society of America}, year = {2012}, volume = {131}, number = {2}, pages = {1226-1239}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857400732&doi=10.1121%2f1.3675942&partnerID=40&md5=2d3fe3fe603f91cc5996aea4205bb3ed}, doi = {https://doi.org/10.1121/1.3675942} } |
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Blake, O., Champoux, Y. and Wakeling, J. | Muscle coordination patterns for efficient cycling | 2012 | Medicine and Science in Sports and Exercise Vol. 44(5), pp. 926-938 |
article | DOI URL |
Abstract: Introduction/Purpose: Cycling is a repetitive activity using coordinated muscle recruitment patterns to apply force to the pedals. With more muscles available for activation than required, some patterns produce high power, whereas some are more efficient. The purpose of this study was to identify relationships between muscle coordination and factors affecting muscle coordination to explain changes in overall mechanical efficiency (?O). Methods: Surface EMG, kinematics, and pedal forces were measured at 25%, 40%, 55%, 60%, 75%, and 90% V?O 2max. Principal component analysis was used to establish muscle coordination, kinematic, and pedal force patterns associated with high and low ?O. Results: At 55%-60% V?O 2max, ?O was maximized and was highly related to the muscle coordination patterns. At high ?O, there was more medial and lateral gastrocnemii and soleus; less gluteus maximus, rectus femoris, and tibialis anterior; later medial and lateral vastii and biceps femoris; and earlier semitendinosus muscle activity resulting in an even distribution and synchronization of peak activity. Also, the ankle was more plantar flexed through the top and downstroke of the pedal cycle and more dorsiflexed during the upstroke for high ?O. The ?O was independent of the pedal force application. Conclusions: The results indicate that increased ?O is achieved through the coordination of muscles crossing the same joint, sequential peak activation from knee to hip to ankle, and reliance on multiple muscles for large joint torques. Also, muscle activity variability across the top and bottom of the cycle indicates that left and right leg muscle coordination may play a significant role in efficient cycling. These findings imply that cycling at 55%-60% V?O 2max will maximize the rider's exposure to high efficient muscle coordination and kinematics. © 2012 by the American College of Sports Medicine. | |||||
BibTeX:
@article{Blake2012926, author = {Blake, O.M. and Champoux, Y. and Wakeling, J.M.}, title = {Muscle coordination patterns for efficient cycling}, journal = {Medicine and Science in Sports and Exercise}, year = {2012}, volume = {44}, number = {5}, pages = {926-938}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859910305&doi=10.1249%2fMSS.0b013e3182404d4b&partnerID=40&md5=df750ce3292763754cd7df6f7500b423}, doi = {https://doi.org/10.1249/MSS.0b013e3182404d4b} } |
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Campolina, B., Atalla, N., Dauchez, N. and Neple, P. | Four-pole modelling of vibration isolators: Application to SEA of aircraft double-wall panels subjected to mechanical excitation | 2012 | Noise Control Engineering Journal Vol. 60(2), pp. 158-170 |
article | DOI URL |
Abstract: This paper aims at determining the structural coupling loss factor (CLF) between two plates connected via vibration isolators, using a four-pole approach. A hybrid Experimental-SEA (statistical energy analysis) model has been developed for predictions and two configurations are analysed. Configuration 1 is composed of two isotropic plates with critical frequencies around 3750 Hz and 6000 Hz. Configuration 2, more representative of an aircraft fuselage, is composed of a stiffened isotropic plate and a sandwich panel. Plates are coupled at 6 locations via elastomeric mounts. They are mechanically excited by a point force at random positions in the 100 to 10000 Hz frequency range. The modelling of the isolators integrates their frequency dependent measured stiffness. Four configurations are compared for the stiffness measurement and the most adapted setup is derived. The modelled CLFs are then compared with measurements using an experimental SEA approach. Finally, the spaceaveraged quadratic velocities of the plates are calculated using the hybrid model and compared with experiments. Results show a good correlation between predicted and measured CLFs but further refinement is needed in order to account for radiation coupling near the critical frequencies of the plates. © 2012 Institute of Noise Control Engineering. | |||||
BibTeX:
@article{Campolina2012158, author = {Campolina, B. and Atalla, N. and Dauchez, N. and Neple, P.}, title = {Four-pole modelling of vibration isolators: Application to SEA of aircraft double-wall panels subjected to mechanical excitation}, journal = {Noise Control Engineering Journal}, year = {2012}, volume = {60}, number = {2}, pages = {158-170}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861618445&doi=10.3397%2f1.3688316&partnerID=40&md5=6a48e5f6ff62e2994e76181a522d3437}, doi = {https://doi.org/10.3397/1.3688316} } |
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Campolina, B., Atalla, N., Dauchez, N. and Neple, P. | Effect of mechanical links on the transmission loss of lightweight double-walls under diffuse acoustic field: Measurements and SEA | 2012 | 41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012 Vol. 3, pp. 1996-2007 |
conference | URL |
Abstract: The effect of structural links on the transmission loss of a double-wall representative of an aircraft sidewall is studied in this paper using Statistical Energy Analysis. The system is composed of: (1) a composite stiffened panel with critical frequency around 4000 Hz, (2) an air gap partially filled with a fibrous layer and (3) a sandwich composite trim panel with critical frequency around 2500 Hz. The skins of the panels are directly connected via either rigid elements or vibration isolators. The structure is subjected to a diffuse acoustic field in the frequency range from 100 Hz to 10 kHz. A transfer path analysis shows that (1) non-resonant airborne transmission dominates in low frequencies, (2) airborne radiation is significant in the critical frequency region of the panels while (3) structure-borne radiation increases the noise transmitted in the mid and high frequency ranges. In addition, for the studied structure, simulations show that isolators provide up to 15 dB of acoustic benefit in the high-frequency range compared to a connection via rigid elements. However, this benefit is found lower on a typical aircraft structural connection in which the trim is linked via frame stiffeners of the fuselage. These results are also validated experimentally. | |||||
BibTeX:
@conference{Campolina20121996, author = {Campolina, B. and Atalla, N. and Dauchez, N. and Neple, P.}, title = {Effect of mechanical links on the transmission loss of lightweight double-walls under diffuse acoustic field: Measurements and SEA}, journal = {41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012}, year = {2012}, volume = {3}, pages = {1996-2007}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883587331&partnerID=40&md5=73f28e381e1edcf597c01dc26b969b9d} } |
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Campolina, B., Dauchez, N., Atalla, N. and Doutres, O. | Effect of porous material compression on the sound transmission of a covered single leaf panel | 2012 | Applied Acoustics Vol. 73(8), pp. 791-797 |
article | DOI URL |
Abstract: In this paper, the authors examine the effect of compressing a poroelastic fibrous layer lined with an isotropic plate on the sound transmission loss (TL). For this purpose, a 2-in. thick fibrous material and two isotropic plates with critical frequencies around 2300 Hz and 9700 Hz were used. The transfer matrix method was applied and the porous layer was assumed to have either a rigid, limp or elastic frame. Current models of compression are outlined, and measurements of the airflow resistivity as a function of compression show that these models are suitable only for low compression rates. TL predictions are compared next to experimental data in a range between 100 Hz and 10000 Hz for three compression rates, corresponding to 0%, 20% and 50%. The fibrous is uniformly compressed over 100% of its surface. Our experiments showed that compression reduces the TL by a maximum of 5 dB for a 50% compression, mainly at the mid-frequency range, around 800 Hz. This is due to a resonance in the thickness of the porous material, increasing the radiation efficiency of the structure at mid-frequencies. Moreover, reduction of the porous thickness and increase of the airflow resistivity with compression are the variations influencing the most the TL of the structure. These trends were also detected with the limp and rigid frame models but with a lower degree of accuracy compared to the elastic frame model. © 2012 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Campolina2012791, author = {Campolina, B. and Dauchez, N. and Atalla, N. and Doutres, O.}, title = {Effect of porous material compression on the sound transmission of a covered single leaf panel}, journal = {Applied Acoustics}, year = {2012}, volume = {73}, number = {8}, pages = {791-797}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861098279&doi=10.1016%2fj.apacoust.2012.02.013&partnerID=40&md5=4ae496627708e80ae03b28b598b3ed5e}, doi = {https://doi.org/10.1016/j.apacoust.2012.02.013} } |
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Caya, A., Champoux, Y. and Drouet, J.-M. | Dynamic behaviour and measurement accuracy of a bicycle brake hood force transducer | 2012 | Procedia Engineering Vol. 34, pp. 526-531 |
conference | DOI URL |
Abstract: To measure road bike load inputs, it is customary to manufacture and instrument a bike component. The purpose of this paper is to investigate the influence of the dynamic behaviour of a brake hood force transducer on measurement accuracy. The majority of the studies reported in the literature on the development of transducers were designed with the objective of having high transducer stiffness in order to increase its first natural frequency to the highest possible degree. This paper shows that, in the case of force transmitted at cyclist's hands, this objective does not lead to the desired results. Rather, the best results are obtained when the natural frequency of the instrumented fabricated component matches that of its standard counterpart. © 2012 Published by Elsevier Ltd. | |||||
BibTeX:
@conference{Caya2012526, author = {Caya, A. and Champoux, Y. and Drouet, J.-M.}, title = {Dynamic behaviour and measurement accuracy of a bicycle brake hood force transducer}, journal = {Procedia Engineering}, year = {2012}, volume = {34}, pages = {526-531}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892612328&doi=10.1016%2fj.proeng.2012.04.090&partnerID=40&md5=172c5ca65993a1719ce28813d8064206}, doi = {https://doi.org/10.1016/j.proeng.2012.04.090} } |
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de Laborderie, J., Moreau, S., Berry, A. and Posson, H. | Several technological effects on tonal fan noise prediction | 2012 | 18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference) | conference | URL |
Abstract: This work aims at evaluating some technological effects usually not included in analytical or semi-analytical tonal fan noise prediction models. The methodology consists in comparing unsteady Computational Fluid Dynamics data, taking successively into account some realistic effects, with the results from a cascade response based model for rotor/stator interaction. The simulations are performed with the turbomachinery flow solver Turb'Flow on a simplified stator vane cascade. They allow evaluating and discussing the effects of both model hypotheses of no vane thickness and inviscid flow on the acoustic sources predictions. The effects of these assumptions are then assessed in terms of modal acoustic powers radiated within the duct. A similar study is performed on a realistic low pressure compressor stage. The effects of the stator vane geometry as well as the real flow configuration on the acoustic sources, extracted during the unsteady simulation, are quantified relatively to the analytical prediction of the vane loading. Finally a comparison of the acoustic powers given by both methods results in an estimation of the technological effects on the propagated noise. © 2012 by the authors. | |||||
BibTeX:
@conference{deLaborderie2012, author = {de Laborderie, J. and Moreau, S. and Berry, A. and Posson, H.}, title = {Several technological effects on tonal fan noise prediction}, journal = {18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference)}, year = {2012}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880621480&partnerID=40&md5=dfa8145b74454b3eb3b0647f2a7bd434} } |
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Doutres, O. and Atalla, N. | Sound absorption properties of functionally graded polyurethane Foams | 2012 | 41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012 Vol. 5, pp. 3737-3746 |
conference | URL |
Abstract: Noise control over a wide frequency band is an increasingly important design criterion in the building and transport industries. Examples of well known broadband passive concepts for optimal sound absorption are multi-layering with graded properties across the thickness and optimization of the material shape (e.g., wedges). However, for typical applications, the material thickness is limited and shaping or use of different material costly. Thus, there is growing interest for developing acoustical materials having microstructure properties gradient at the micro- or meso-scale; also known as Functionally Graded Materials (FGM). Even if sophisticated models are available to predict the acoustic behavior of homogeneous and multilayered acoustical materials, there is still a need for a better understanding of FGM for sound absorption. More specifically, does a graded foam material always improve the acoustic behavior compared to a homogeneous one? This presentation proposes to answer this question by investigating numerically, using a microstructure model, the effect of varying the reticulation rate along the thickness of a highly porous polyurethane foam. | |||||
BibTeX:
@conference{Doutres20123737, author = {Doutres, O. and Atalla, N.}, title = {Sound absorption properties of functionally graded polyurethane Foams}, journal = {41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012}, year = {2012}, volume = {5}, pages = {3737-3746}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883586598&partnerID=40&md5=3452e7b52928b23161c50a92c109f9f9} } |
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Drouet, J.-M. and Champoux, Y. | Development of a three-load component instrumented stem for road cycling | 2012 | Procedia Engineering Vol. 34, pp. 502-507 |
conference | DOI URL |
Abstract: The aim of this research was to develop an instrumented road bike stem to enable in situ measurements of static and dynamic loads transmitted through the stem-handlebar connection. Our stem is instrumented with twelve strain gauges and enables measurement of the vertical force and two moment components. Calibration and in situ measurements demonstrated that the instrumented stem provides accurate measurements for small and large loads. This paper presents the results for stem loads when climbing a hill out of the saddle and during road impact. © 2012 Published by Elsevier Ltd. | |||||
BibTeX:
@conference{Drouet2012502, author = {Drouet, J.-M. and Champoux, Y.}, title = {Development of a three-load component instrumented stem for road cycling}, journal = {Procedia Engineering}, year = {2012}, volume = {34}, pages = {502-507}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889601860&doi=10.1016%2fj.proeng.2012.04.086&partnerID=40&md5=9ce2df4e8ee7c07d5d6d6d4c078c451b}, doi = {https://doi.org/10.1016/j.proeng.2012.04.086} } |
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Gauthier, J.-P. and Micheau, P. | Regularized RLS-? and DHOBE: An adaptive feedforward for a solenoid valve | 2012 | IEEE Transactions on Control Systems Technology Vol. 20(5), pp. 1311-1318 |
article | DOI URL |
Abstract: To allow a stable and fast acting hydraulic pressure control on a continuously variable transmission (CVT) for road vehicles, an adaptive feedforward strategy is used. The Dasgupta-Huang outer bounding ellipsoid (DHOBE) and recursive least squares (RLS) with exponential forgetting factor (RLS-?) adaptation algorithms are compared to the non-adaptive feedforward. The experiments show a clear advantage for the adaptive over the non-adaptive version by compensating for the slow drift of the valve pressure gain during the warm-up period of the transmission. Because of highly correlated input data, the adaptation algorithms offer deceiving performances with oscillating identified parameters. A regularization procedure is added to both adaptation algorithms, giving the rRLS-? and rDHOBE. The regularized algorithms offer significantly better performances and stability than their non-regularized counterparts. Because of its implicit parametric uncertainty calculation while keeping an equivalent convergence rate, and a lower number of updates, the rDHOBE algorithm is regarded as the best solution for the application. By adapting a simple linear model, the rDHOBE adaptive feedforward succeeds in responding to an abrupt change of the external pressure setpoint with no added actuation delay while keeping the pressure error under 0.5 bar. © 2011 IEEE. | |||||
BibTeX:
@article{Gauthier20121311, author = {Gauthier, J.-P. and Micheau, P.}, title = {Regularized RLS-? and DHOBE: An adaptive feedforward for a solenoid valve}, journal = {IEEE Transactions on Control Systems Technology}, year = {2012}, volume = {20}, number = {5}, pages = {1311-1318}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84863524012&doi=10.1109%2fTCST.2011.2160641&partnerID=40&md5=ddad25661d9412f1286a6c3d4e71ef9a}, doi = {https://doi.org/10.1109/TCST.2011.2160641} } |
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Gauthier, J.-P. and Micheau, P. | Feedfoward and feedback adaptive controls for continuously variable transmissions | 2012 | IFAC Proceedings Volumes (IFAC-PapersOnline) Vol. 16(PART 1), pp. 1460-1465 |
conference | DOI URL |
Abstract: Continuously variable transmissions (CVT) require a feedback controller to reach a targeted transmission speed ratio by commanding pressures on moveable sheaves. The implementation of two on-line identification algorithms are presented to improve the performances and the robutness of the CVT. To compensate for the slow drift of the electro-hydraulic valves during the warm-up period of the transmission, an adaptive feedforward strategy is implemented with the Dasgupta-Huang Outer Bounding Ellipsoid (DHOBE); because of highly correlated input data, a regularization procedure is added, giving the rDHOBE. To compensate for the effect of wear on the pulleys, an improved feedback linearization design is proposed with an on-line adaption of the main nonlinear map in a neural associative memory. The adaptation is required because the stability condition of the feedback controller depends of the accuracy of one of the estimated non-linear maps. The experiments show clear advantages for such adaptive controls over non-adaptive ones. © 2012 IFAC. | |||||
BibTeX:
@conference{Gauthier20121460, author = {Gauthier, J.-P. and Micheau, P.}, title = {Feedfoward and feedback adaptive controls for continuously variable transmissions}, journal = {IFAC Proceedings Volumes (IFAC-PapersOnline)}, year = {2012}, volume = {16}, number = {PART 1}, pages = {1460-1465}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867071341&doi=10.3182%2f20120711-3-BE-2027.00401&partnerID=40&md5=52dd2ded6700b4a58e226e66572f42d2}, doi = {https://doi.org/10.3182/20120711-3-BE-2027.00401} } |
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Gauthier, J.-P. and Micheau, P. | Adaptive control of a continuously variable transmission subject to wear | 2012 | Control Engineering Practice Vol. 20(6), pp. 569-574 |
article | DOI URL |
Abstract: Continuously variable transmissions (CVT) require an electronic controller for real application: it must reach a targeted transmission speed ratio in spite of wear. Based on our recent model based for high speed steel belt CVT, an improved feedback linearization design is proposed with an on-line adaption of the main nonlinear map in a neural associative memory. The adaptation is required because the stability condition depends of the accuracy of the estimated nonlinear map. Experimental results show that the adaptation allows the speed ratio controller to remain stable regardless of the wear accumulated by the CVT transmission. © 2012 Elsevier Ltd. | |||||
BibTeX:
@article{Gauthier2012569, author = {Gauthier, J.-P. and Micheau, P.}, title = {Adaptive control of a continuously variable transmission subject to wear}, journal = {Control Engineering Practice}, year = {2012}, volume = {20}, number = {6}, pages = {569-574}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859619395&doi=10.1016%2fj.conengprac.2012.02.001&partnerID=40&md5=ca70e5ded84ed6148ca48d010598eb58}, doi = {https://doi.org/10.1016/j.conengprac.2012.02.001} } |
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Gauthier, P.-A., Camier, C., Lebel, F.-A., Pasco, Y. and Berry, A. | Experiments of sound field reproduction inside aircraft cabin mock-up | 2012 | 133rd Audio Engineering Society Convention 2012, AES 2012 Vol. 2, pp. 759-776 |
conference | URL |
Abstract: Sound environment reproduction of various flight conditions in aircraft mock-ups is a valuable tool for the study, prediction, demonstration and jury testing of interior aircraft sound quality and comfort. To provide a faithful reproduced sound environment, time, frequency and spatial characteristics should be preserved. Physical sound field reproduction approaches for spatial sound reproduction are mandatory to immerse the listener body in the proper sound field so that localization cues are recreated. Vehicle mock-ups pose specific problems for sound field reproduction. Confined spaces, needs for invisible sound sources and a singular acoustical environment make the use of open-loop sound field reproduction technologies not ideal. In this paper, preliminary experiments in an aircraft mock-up with classical multichannel least-square methods are reported. The paper presents objective evaluations of reproduced sound fields. Promising results along with practical compromises are reported. | |||||
BibTeX:
@conference{Gauthier2012759, author = {Gauthier, P.-A. and Camier, C. and Lebel, F.-A. and Pasco, Y. and Berry, A.}, title = {Experiments of sound field reproduction inside aircraft cabin mock-up}, journal = {133rd Audio Engineering Society Convention 2012, AES 2012}, year = {2012}, volume = {2}, pages = {759-776}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876537606&partnerID=40&md5=424b41e7fd8d909f7c26d1c511dc6384} } |
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Gérard, A., Moreau, S., Berry, A. and Masson, P. | Multi modal obstruction to control tonal fan noise: Theory and experiments | 2012 | ISROMAC 2012 - 14th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery | conference | URL |
Abstract: The approach presented in this paper uses a combination of obstructions in the upstream flow of subsonic axial fans to destructively interfere with the primary tonal noise at the blade passage frequency. The first step of the proposed experimental method consists on identifying the independent radiation of B-1 and B lobed obstructions at the control microphones. During the identification step, rotating obstructions allow for the frequencies of primary and secondary tonal noise to be slightly shifted in the spectrum due to acoustic modulation effect. The magnitude of the secondary tonal noise generated by each obstruction can be adjusted by varying the size of the lobes of the obstruction, and the phase of the secondary tonal noise is related to the angular position of the obstruction. The control obstructions are then optimized by combining the B-1 and B lobed obstructions to significantly reduce the acoustic power at BPF. | |||||
BibTeX:
@conference{Gérard2012, author = {Gérard, A. and Moreau, S. and Berry, A. and Masson, P.}, title = {Multi modal obstruction to control tonal fan noise: Theory and experiments}, journal = {ISROMAC 2012 - 14th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery}, year = {2012}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84905717463&partnerID=40&md5=9d21a7c0ec5142c5fa42b966ec0ab20f} } |
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Gérard, A., Berry, A., Masson, P. and Moreau, S. | Semi-active method to control tonal noise from fans | 2012 | 41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012 Vol. 2, pp. 1241-1252 |
conference | URL |
Abstract: Tonal noise originates from non-uniform flow that causes circumferentially varying blade forces and gives rise to a considerably larger radiated dipolar sound at the blade passage frequency and its harmonics. This paper presents an overview of a semi-active method to control tonal fan noise from axial and centrifugal fans using obstruction in the flow to destructively interfere with the primary non-uniform inlet flow. The flow control obstruction is located such that the secondary radiated noise is of equal magnitude but opposite in phase compared to the primary noise. Several analytical, numerical and experimental methods to design and to locate the obstruction are summarized. | |||||
BibTeX:
@conference{Gérard20121241, author = {Gérard, A. and Berry, A. and Masson, P. and Moreau, S.}, title = {Semi-active method to control tonal noise from fans}, journal = {41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012}, year = {2012}, volume = {2}, pages = {1241-1252}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883589878&partnerID=40&md5=fbe36fa668439b23c68c887c85b4b908} } |
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Ghaffari Mosanenzadeh, S., Naguib, H., Park, C. and Atalla, N. | A study on the acoustic performance of bio-based composite foams of PLA and PHBV | 2012 | Annual Technical Conference - ANTEC, Conference Proceedings Vol. 3, pp. 2503-2509 |
conference | URL |
Abstract: Bio-based foams are the solution to environmental concerns regarding petrochemical-based foams. However, bio-based foams possess weak structure. To increase the potential of replacing current petrochemical foams, mechanical characteristics of bio-based foams need to be improved. This paper studies the effect of blending two bio-based polymers on mechanical and acoustic properties of resulting polymer composite foams. Blends of Polylactide (PLA) and polyhydroxybutyrate-co-valerate (PHBV) were foamed and characterized in terms of acoustic, mechanical properties and foam morphology. | |||||
BibTeX:
@conference{GhaffariMosanenzadeh20122503, author = {Ghaffari Mosanenzadeh, S. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {A study on the acoustic performance of bio-based composite foams of PLA and PHBV}, journal = {Annual Technical Conference - ANTEC, Conference Proceedings}, year = {2012}, volume = {3}, pages = {2503-2509}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865832498&partnerID=40&md5=98ec56725d733fa148d38557c8dde2f8} } |
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Lépine, J., Champoux, Y. and Drouet, J.-M. | Technique to measure the dynamic behavior of road bike wheels | 2012 | Conference Proceedings of the Society for Experimental Mechanics Series Vol. 6, pp. 465-470 |
conference | DOI URL |
Abstract: In the quest to improve comfort in road cycling, a primary concern of the bike manufacturing industry is the vibration generated by the road and transmitted to the cyclist's hands and buttocks. The bike wheels are considered to be one of the major components contributing to the bike's vibration isolation. In this paper, we describe a technique that uses the measurement of a blocked force at the hub. A road simulator was used to impose a controlled white noise vertical displacement under the tire. Measurements were taken of the force under the tire and the blocked force at the wheel hub. Six different wheels were tested. When the force was applied at different locations on the wheel, some of the wheels showed important spatial variations of the blocked force. The results show that this technique is successful in differentiating and ranking the wheels. Each wheel was also characterized by its radial static stiffness. Preliminary results show that there is poor correlation R 2 = 0.41 between radial static stiffness and the blocked force at the dynamic hub. © The Society for Experimental Mechanics, Inc. 2012. | |||||
BibTeX:
@conference{Lépine2012465, author = {Lépine, J. and Champoux, Y. and Drouet, J.-M.}, title = {Technique to measure the dynamic behavior of road bike wheels}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2012}, volume = {6}, pages = {465-470}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864005114&doi=10.1007%2f978-1-4614-2419-2_47&partnerID=40&md5=9e2df2507790edb93a63e7c8a807a791}, doi = {https://doi.org/10.1007/978-1-4614-2419-2_47} } |
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Mejdi, A. and Atalla, N. | Vibroacoustic analysis of laminated composite panels stiffened by complex laminated composite stiffeners | 2012 | International Journal of Mechanical Sciences Vol. 58(1), pp. 13-26 |
article | DOI URL |
Abstract: This paper investigates the vibroacoustic behavior of stiffened composite panels. Airborne and structure borne excitations are considered. Two models are presented. The first is based on the modal expansion technique and handles both symmetric and asymmetric laminate composite panels and stiffening beams. It uses the first order shear deformation theory for the skin and accounts for the in-plane/bending effects, cross modal coupling and eccentricity of the stiffening beams. The latter are accounted for using equivalent forces and moments and integrated in the skin model using the continuity relations. The second model uses the equivalent properties of the composite panel and beams to extend an existing model, widely used in statistical energy analysis (SEA) of stiffened metallic structures, to composite stiffened structures. Composite panels reinforced by composite stiffeners with three types of cross-sections (I, C and omega) are analyzed. Both irregularly and periodically stiffened panels are studied and compared to the finite element (FEM) for the vibration response and boundary element methods (BEM) for the acoustic response. In FEM simulations, the stiffeners are modeled as surfaces assembly in order to highlight their in-plane displacements and their deformations effects. Excellent agreement with the FEM/BEN analysis is observed in all investigated configurations. © 2012 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Mejdi201213, author = {Mejdi, A. and Atalla, N.}, title = {Vibroacoustic analysis of laminated composite panels stiffened by complex laminated composite stiffeners}, journal = {International Journal of Mechanical Sciences}, year = {2012}, volume = {58}, number = {1}, pages = {13-26}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859856127&doi=10.1016%2fj.ijmecsci.2012.02.003&partnerID=40&md5=c5dd28a06e7d3f659dc03f57c1a4ebf5}, doi = {https://doi.org/10.1016/j.ijmecsci.2012.02.003} } |
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Mejdi, A., Legault, J. and Atalla, N. | Transmission loss of periodically stiffened laminate composite panels: Shear deformation and in-plane interaction effects | 2012 | Journal of the Acoustical Society of America Vol. 131(1), pp. 174-185 |
article | DOI URL |
Abstract: This paper investigates the transmission loss of symmetric and asymmetric laminate composite panels periodically reinforced by composite stiffeners. A comprehensive model based on periodic structure theory is developed. First order shear deformation theory is used and the coupling of the in-plane motion of the panel with its out-of-plane motion is taken into account. Stiffeners interact with the panel through three forces (two in-plane, one out-of-plane) and a torsion moment. Three types of cross sections are investigated for the composite stiffeners: I-shaped, C-shaped, and omega-shaped cross-sections. The model is validated numerically by comparison with the finite elementboundary element method. Experimental validations are also conducted. In both cases, excellent agreement is obtained. Numerical results show that the in-plane coupling effect is increased by increasing the panel thickness and the stiffener's eccentricity. The in-plane coupling effect is also found to increase with frequency. © 2012 Acoustical Society of America. | |||||
BibTeX:
@article{Mejdi2012174, author = {Mejdi, A. and Legault, J. and Atalla, N.}, title = {Transmission loss of periodically stiffened laminate composite panels: Shear deformation and in-plane interaction effects}, journal = {Journal of the Acoustical Society of America}, year = {2012}, volume = {131}, number = {1}, pages = {174-185}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84855934654&doi=10.1121%2f1.3664093&partnerID=40&md5=93b97022383c8ae5d350925beea236fa}, doi = {https://doi.org/10.1121/1.3664093} } |
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Mohamed, R., Yazdanpanah, P. and Masson, P. | A generalized equivalent loading model for piezoelectric elements | 2012 | Proceedings of the 6th European Workshop - Structural Health Monitoring 2012, EWSHM 2012 Vol. 1, pp. 871-878 |
conference | URL |
Abstract: Typically, an active structural health monitoring system (SHM) consists of an integrated network of actuator/sensor piezoceramic elements that inject and receive ultrasound pulses into the host structure collecting information about structural health. Although numerical simulation has been used extensively in understanding and aiding in the design of such systems, analytical models are still the primary vehicle for understanding actuation and sensing mechanisms. Being based on simplified assumptions it suffers from certain limitations with respect to its extension to SHM systems. The main assumption of equivalent loading is neglecting the mechanical coupling by replacing the piezoceramic with equivalent load(s). The present work addresses two of the limitations of this assumption, namely the effect of the thickness of the piezoceramic element on the equivalent load in dynamic setting at high frequency. This study is done via a novel formulation based on earlier work considering Lamb waves as a propagating carrier wave with superimposed modes which is not limited to isotropic media and the inclusion of the generalized loads are done via the reciprocity relation. The model results are compared with the numerical simulation results using commercial finite element software (ANSYS) for a wide range of frequencies. The applicability of the model to frequencies as large as 0,5 MHz is demonstrated. The effect of the loading on the energy partitioning between Lamb fundamental modes, without the need for prior adjustment comes as the first advantage of the presented model over the classical integral transform based models, thus enabling a direct relation for mode tuning. The second advantage is the easy inclusion of the finite frequency content of the excitation through Fourier transform, relaxing the assumption of harmonic waves propagation that prevails in the classical models enabling a more realistic signal to be modeled. | |||||
BibTeX:
@conference{Mohamed2012871, author = {Mohamed, R. and Yazdanpanah, P.M. and Masson, P.}, title = {A generalized equivalent loading model for piezoelectric elements}, journal = {Proceedings of the 6th European Workshop - Structural Health Monitoring 2012, EWSHM 2012}, year = {2012}, volume = {1}, pages = {871-878}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894794396&partnerID=40&md5=bc91d2855c7eb77dd29462ffbffd69b5} } |
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Mosanenzadeh, S., Naguib, H., Park, C. and Atalla, N. | Development of bio-based foams with improved acoustic and mechanical performance | 2012 | American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCAD, pp. 497-504 | conference | DOI URL |
Abstract: Interest in noise control has been growing in recent years and efforts are under way to improve the acoustic performance of existing sound absorbers and also to replace the nonrecyclable ones with environmentally friendly materials. Present study describes the research on fabrication, improvement of acoustic absorption and enhancement of mechanical strength of bio-based open-cell foams. Through this study, highly porous open-cell Polylactide (PLA) foams were fabricated by a new fabrication method combining particulate leaching technique and compression molding. Foamed structures were fabricated with PLA and Polyethylene glycol (PEG) with salt as the particulate. Pore size of the foam was controlled by salt particulates and higher interconnectivity was achieved by the co-continuous blending morphology of PLA matrix with water-soluble PEG. As a result of novel secondary porous structure, acoustic performance of PLA foams was successfully improved. One issue with application of bio-based open-cell foams is the weak structure. To improve mechanical characteristics of PLA foams, different polymer composites of PLA and Polyhydroxyalkanoate (PHA) were foamed and characterized in terms of acoustic performance, mechanical properties and foam morphology. Polymers used in this study are bio-based which is of great importance considering huge amount of foams used as acoustic absorbers in various industries. Copyright © 2012 by ASME. | |||||
BibTeX:
@conference{Mosanenzadeh2012497, author = {Mosanenzadeh, S.G. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {Development of bio-based foams with improved acoustic and mechanical performance}, journal = {American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCAD}, year = {2012}, pages = {497-504}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884837837&doi=10.1115%2fNCAD2012-1262&partnerID=40&md5=10bd363f40bea6510f96b991a60457d9}, doi = {https://doi.org/10.1115/NCAD2012-1262} } |
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Mosanenzadeh, S., Park, C., Naguib, H. and Atalla, N. | Development of bio-based foams with improved acoustic and mechanical performance | 2012 | 41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012 Vol. 7, pp. 5978-5985 |
conference | URL |
Abstract: Interest in noise control has been growing in recent years and efforts are under way to improve the acoustic performance of existing sound absorbers and also to replace the non- recyclable ones with environmentally friendly materials. Present study describes the research on fabrication, improvement of acoustic absorption and enhancement of mechanical strength of bio-based open-cell foams. Through this study, highly porous open-cell Polylactide (PLA) foams were fabricated by a new fabrication method combining particulate leaching technique and compression molding. Foamed structures were fabricated with PLA and Polyethylene glycol (PEG) with salt as the particulate. Pore size of the foam was controlled by salt particulates and higher interconnectivity was achieved by the co-continuous blending morphology of PLA matrix with water-soluble PEG. As a result of novel secondary porous structure, acoustic performance of PLA foams was successfully improved. One issue with application of bio-based open-cell foams is the weak structure. To improve mechanical characteristics of PLA foams, different polymer composites of PLA and Polyhydroxyallcanoate (PHA) were foamed and characterized in terms of acoustic performance, mechanical properties and foam morphology. Polymers used in this study are bio-based which is of great importance considering huge amount of foams used as acoustic absorbers in various industries. | |||||
BibTeX:
@conference{Mosanenzadeh20125978, author = {Mosanenzadeh, S.G. and Park, C.B. and Naguib, H.E. and Atalla, N.}, title = {Development of bio-based foams with improved acoustic and mechanical performance}, journal = {41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012}, year = {2012}, volume = {7}, pages = {5978-5985}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883582833&partnerID=40&md5=3e5e72c6e58f0b25b0af3396b31bb495} } |
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Mulligan, K., Quaegebeur, N., Masson, P. and Létourneau, S. | Correction of data gathered by degraded transducers for damage prognosis in composite structures | 2012 | Proceedings of the Annual Conference of the Prognostics and Health Management Society 2012, PHM 2012, pp. 103-110 | conference | URL |
Abstract: This paper presents an approach for the correction of data gathered for damage prognosis (DP) in composite structures. The validation setup consists of surface-bonded piezoceramic (PZT) transducers used in a Structural Health Monitoring (SHM) system with simulated bonding layer damage using Teflon masks. The modal damping around PZT mechanical resonance is used as a metric to assess and compensate for the degradation of the adhesive layer of the transducers. Modal damping is derived from electrical admittance curves using a lumped parameter model to monitor the degradation of the transducer adhesive layer. A Pitch-Catch (PC) configuration is then used to discriminate the effect of bonding degradation on actuation and sensing. It is shown that below the first mechanical resonance frequency of the PZT, degradation leads to a decrease in the amplitude of the transmitted and measured signals. Above resonance, in addition to a decrease in signal amplitude of the transmitted and measured signals, a slight linear phase delay is also observed. A Signal Correction Factor (SCF) is proposed to adjust signals based on adhesive degradation evaluated using the measured modal damping. The benefits of the SCF for prognostics feature generation are demonstrated in the frequency domain for the A0 mode. | |||||
BibTeX:
@conference{Mulligan2012103, author = {Mulligan, K.R. and Quaegebeur, N. and Masson, P. and Létourneau, S.}, title = {Correction of data gathered by degraded transducers for damage prognosis in composite structures}, journal = {Proceedings of the Annual Conference of the Prognostics and Health Management Society 2012, PHM 2012}, year = {2012}, pages = {103-110}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920523010&partnerID=40&md5=6b797e52644353291cb12059023684fa} } |
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Neple, P., Atalla, N. and Bolduc, M. | Aircraft soft mount efficiency: Sensitivity to temperature and preloading | 2012 | 41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012 Vol. 5, pp. 4365-4374 |
conference | URL |
Abstract: The general context of this study is the improvement of the optimization of the decoupling devices used to decrease aircraft interior noise due to structure-borne transmission. The main objective of this paper is to focus on the temperature and preloading effects on mount efficiency. The dynamic stiffness has been first measured for one set of mounts between -40°C and +20°C by step of 10°C in the [50-3000Hz] frequency range. The measurements have been made for those temperatures with and without preloading. The preload was realized by applying initial displacements equal to 1 and 2 mm. It appears that decreasing the temperature clearly increases the dynamic stiffness (by approximately 20% for a step of +20°C). In addition the initial displacement effect on mount dynamic stiffness is more complex (there is no obvious increase or decrease compared to configuration without initial displacement) and variations remain lower than 10% for a fixed temperature. Finally, measurements of the transmissibility ratio between two unstiffened aluminum plates attached by the tested mounts have been made in the temperature and frequency ranges identical to the ones used for dynamic stiffness determination. No initial displacement has been applied in that case, and the excitation was made by a shaker. The main result is a 2dB vibration level increase per each step of +10°C temperature decrease. | |||||
BibTeX:
@conference{Neple20124365, author = {Neple, P. and Atalla, N. and Bolduc, M.}, title = {Aircraft soft mount efficiency: Sensitivity to temperature and preloading}, journal = {41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012}, year = {2012}, volume = {5}, pages = {4365-4374}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883583780&partnerID=40&md5=e54ebedd9c895d1cc22ce9636b664e97} } |
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Ostiguy, P.-C., Quaegebeur, N. and Masson, P. | Assessment of the Excitelet algorithm for in-situ mechanical characterization of orthotropic structures | 2012 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 8348 |
conference | DOI URL |
Abstract: Damage detection and localization on composites can be impaired by inaccurate knowledge of the mechanical properties of the structure. This paper demonstrates the feasibility of using a chirplet-based correlation technique, called Excitelet, to evaluate the mechanical properties of orthotropic carbon fibre-based composite laminates. The method relies on the identification of an optimal correlation coefficient between measured and simulated dispersed signals measured on a structure using piezoceramic (PZT) transducers. Finite Element Model (FEM) is first conducted to demonstrate the capability of the approach to evaluate the mechanical properties of a composite structure. Experimental validation is then conducted on a unidirectionnal 2.30 mm thick laminate composed of unidirectional plies and a 2.35 mm thick laminate composed of unidirectional plies oriented at [0, 90] 4s. Surface bonded PZT transducers were used both for actuation and sensing of guided waves bursts measured at 0° and 90° with respect to upper ply fibre orientation. The characterization is performed at various frequencies below 100 kHz using A 0 or S 0 modes and comparison with the material properties measured following ASTM standard testing is presented. The results indicate that large correlation coefficients are obtained between the measurements and simulated signals for both A 0 and S 0 modes when accurate properties are used as inputs for the model. Strategies based on multiple modes correlation are also assessed in order to improve the accuracy of the characterization approach. The results obtained using the proposed approach for the unidirectional plate and most of the results obtained using the proposed approach for the [0, 90] 4s laminate are in agreement with the uncertainty associated with ASTM tests results while the proposed method is non destructive and can be performed prior to each imaging processing. © 2012 SPIE. | |||||
BibTeX:
@conference{Ostiguy2012, author = {Ostiguy, P.-C. and Quaegebeur, N. and Masson, P.}, title = {Assessment of the Excitelet algorithm for in-situ mechanical characterization of orthotropic structures}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2012}, volume = {8348}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861722844&doi=10.1117%2f12.914842&partnerID=40&md5=35d9ea56a030e2a67d8d1897f73a9672}, doi = {https://doi.org/10.1117/12.914842} } |
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Ostiguy, P.-C., Quaegebeur, N., Mulligan, K., Masson, P. and Elkoun, S. | In situ mechanical characterization of isotropic structures using guided wave propagation | 2012 | Smart Materials and Structures Vol. 21(6) |
article | DOI URL |
Abstract: Guided waves are widely used in structural health monitoring (SHM). Their behaviour is highly sensitive to the mechanical properties of a structure. The performance of damage detection strategies based on guided waves therefore relies on an accurate knowledge of the mechanical properties. This paper presents an integrated characterization technique that identifies the mechanical properties of isotropic structures, namely the elastic modulus and Poissons ratio. The approach is based on a modified version of an imaging algorithm (Excitelet), where mechanical properties, instead of geometrical scattering features, are set as the variables to be identified. The methodology, accuracy, repeatability, and robustness are assessed, first via a finite element model (FEM) and then experimentally for an aluminum plate with attached piezoceramic (PZT) transducers. The plate is instrumented with two PZTs located 15cm from each other in a pitchcatch configuration, distant enough to ensure proper mode discrimination. The algorithm accuracy and robustness with respect to slight variations in the geometrical inputs (PZT to PZT distance and thickness of the plate) are validated within ±1% and ±2%, respectively, with the FEM. Experimental results are validated within ±1% of supplier properties, demonstrating the ability of this approach to allow accurate characterization of a structure in situ without the need for complex and expensive devices or ASTM testing. © 2012 IOP Publishing Ltd. | |||||
BibTeX:
@article{Ostiguy2012, author = {Ostiguy, P.-C. and Quaegebeur, N. and Mulligan, K.R. and Masson, P. and Elkoun, S.}, title = {In situ mechanical characterization of isotropic structures using guided wave propagation}, journal = {Smart Materials and Structures}, year = {2012}, volume = {21}, number = {6}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861878167&doi=10.1088%2f0964-1726%2f21%2f6%2f065010&partnerID=40&md5=ff51dde59745e2a31a0028192cce4cb7}, doi = {https://doi.org/10.1088/0964-1726/21/6/065010} } |
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Ostiguy, P.-C., Quaegebeur, N. and Masson, P. | In situ damping characterization for improved imaging in structural health monitoring | 2012 | Proceedings of the 6th European Workshop - Structural Health Monitoring 2012, EWSHM 2012 Vol. 1, pp. 900-907 |
conference | URL |
Abstract: The damping of a material affects the distance over which guided waves can travel, determining the effective area of a structure which can be monitored by a given configuration of actuators and sensors in structural health monitoring (SHM). The attenuation of waves practically limits the efficiency of damage imaging approaches based on Time of Flight. More recent damage strategies exploiting propagation models such as Excitelet rely on the knowledge of material properties and damping has not been considered up to now. This paper presents the preliminary results of a method based on guided wave propagation for in-situ estimation of material damping. This parameter, together with other parameters such as Young's modulus, Poisson's ratio and density, could then be used in the propagation models used for damage imaging. The method evaluates the attenuation of a material by correlating time domain measurements, with model-based predicted dispersed versions of an excitation signal, generated by a piezoceramic actuator. Predicted dispersed versions of the excitation signal are generated by a propagation models using complex wave numbers, where the imaginary parts represent the damping coefficient. The approach is first validated numerically using a finite element model (FEM) of three isotropic structures having different damping coefficients. In these models, the generation of a windowed burst onto the structure is simulated using an actuating bonded PZT. The time signal of the generated burst at the emitter is dispersed using propagation models. The damping is estimated using a genetic algorithm, by finding the optimal complex wave numbers in the propagation model leading to the highest correlation between the FEM measurement measured and the model-based predicted dispersed time signals. An experimental assessment of the approach is then carried out on a 2.33 mm thick composite plate. Measurement points are taken using Lased Doppler Vibrometer (LDV). The results obtained in this work show the potential of the approach to estimate accurately the damping of a material. | |||||
BibTeX:
@conference{Ostiguy2012900, author = {Ostiguy, P.-C. and Quaegebeur, N. and Masson, P.}, title = {In situ damping characterization for improved imaging in structural health monitoring}, journal = {Proceedings of the 6th European Workshop - Structural Health Monitoring 2012, EWSHM 2012}, year = {2012}, volume = {1}, pages = {900-907}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894731286&partnerID=40&md5=4a6711670290229bd4a6c83dc487defb} } |
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Panneton, R. | University training courses in acoustics and vibration at the University of Sherbrooke [Formations universitaires en acoustique et en contrôle du bruit à l'université de sherbrooke] | 2012 | Canadian Acoustics - Acoustique Canadienne Vol. 40(2), pp. 3-9 |
article | URL |
Abstract: In the Department of Mechanical Engineering at the Université de Sherbrooke, several professors and researchers are pooling complementary expertise in acoustics and vibration in a University research center, the Acoustics Group of the Université de Sherbrooke (GAUS). This pooling of expertise and infrastructure provides an environment conducive to research, technology transfer and specialized training in acoustics and vibration. For the training component, several courses are for undergraduate and graduate students in engineering who wish to specialize in this area. This paper presents the various training courses in acoustics and vibration that are offered by the Department of Mechanical Engineering at the Université de Sherbrooke, and an overview of the related main teaching activities. | |||||
BibTeX:
@article{Panneton20123, author = {Panneton, R.}, title = {University training courses in acoustics and vibration at the University of Sherbrooke [Formations universitaires en acoustique et en contrôle du bruit à l'université de sherbrooke]}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2012}, volume = {40}, number = {2}, pages = {3-9}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84863694799&partnerID=40&md5=7b5062559810cc0129185996af83000f} } |
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Panneton, R., Verdière, K., Elkoun, S., Dupont, T. and Leclaire, P. | Transfer matrix modeling and numerical verification of locally reacting acoustic mosaics | 2012 | 41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012 Vol. 5, pp. 3716-3724 |
conference | URL |
Abstract: This paper deals with the modeling of the acoustic behavior (absorption and transmission) of an acoustic mosaic having heterogeneous surface properties. On the surface, the material can be viewed as a collection of independent cells reacting locally. Each cell is filled with an absorbent material different from its neighbors. Such a mosaic may be seen as a generalization of the typical case of a honeycomb liner filled with absorbent materials. The originality of the study lies in the modeling of such heterogeneous material by an Admittance Sum Method (ASM) and a Transfer Matrix Method (TMM). The transfer matrix modeling of the heterogeneous material uses the summation of parallel arrays to form the transfer matrix of the mosaic. Using a finite element model of a measuring impedance tube, the proposed developments are checked on an acoustic mosaic built from three periodic cells filled with a mixture of flax fibers with different levels of compaction. Two configurations (one for sound absorption, one for sound transmission) are studied under normal incidence plane wave excitation. It is shown that the developed ASM and TMM give good correlation with finite element simulations when the mosaic is backed by a hard wall. When the mosaic is backed by a layer of air or anechoic end, only the transfer matrix method gives good results. | |||||
BibTeX:
@conference{Panneton20123716, author = {Panneton, R. and Verdière, K. and Elkoun, S. and Dupont, T. and Leclaire, P.}, title = {Transfer matrix modeling and numerical verification of locally reacting acoustic mosaics}, journal = {41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012}, year = {2012}, volume = {5}, pages = {3716-3724}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883563066&partnerID=40&md5=663163ee1f39fa6daa4a66d82fe92fec} } |
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Perrier, S., Champoux, Y. and Drouet, J.-M. | Using substructuring to predict the human hand influence on a mechanical structure | 2012 | Conference Proceedings of the Society for Experimental Mechanics Series Vol. 2, pp. 33-44 |
conference | DOI URL |
Abstract: Substructuring methods have been widely used on mechanical structures to study and improve the dynamic behavior of complex assemblies by analyzing the behavior of each substructure separately. Substructuring methods can potentially be used to create a functional link between the dynamic behavior of the human body and mechanical structures in order to enhance the interactions between the body and these same structures. Keeping in mind that significant amounts of vibrations are transmitted to the body from contact with vibrating structures - human-structure coupling interactions could be used as a way to study components of comfort during vibration exposure, and even with the goal of preventing injuries caused by transmitted vibration. This paper investigates a coupling between a straight beam and the hand-arm system which is a non-linear structure. Each structure is characterized by experimentally obtained mechanical mobility Frequency Response Function (FRF) data over a frequency range between [5, 300] Hz. The FRF Based Substructuring method (FBS) allows coupling through the interface set of substructures. This links mechanical structures with the human body where only interface measurements are gathered. The FBS method is used to predict the dynamic behavior of the assembly. © The Society for Experimental Mechanics, Inc. 2012. | |||||
BibTeX:
@conference{Perrier201233, author = {Perrier, S. and Champoux, Y. and Drouet, J.-M.}, title = {Using substructuring to predict the human hand influence on a mechanical structure}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2012}, volume = {2}, pages = {33-44}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861757332&doi=10.1007%2f978-1-4614-2422-2_4&partnerID=40&md5=818f5b463bbc84cac4e85e2c04f7c902}, doi = {https://doi.org/10.1007/978-1-4614-2422-2_4} } |
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Quaegebeur, N., Micheau, P., Masson, P. and Castaings, M. | Methodology for optimal configuration in structural health monitoring of composite bonded joints | 2012 | Smart Materials and Structures Vol. 21(10) |
article | DOI URL |
Abstract: In this study, a structural health monitoring (SHM) strategy is proposed in order to detect disbonds in a composite lap-joint. The structure under study is composed of a carbon fiber reinforced polymer (CFRP) bonded to a titanium plate and artificial disbonds are simulated by inserting Teflon tapes of various dimensions within the joint. Insitu inspection is ensured by piezoceramics bonded to the structure to generate and measure guided waves. Theoretical propagation and through-thickness stress distribution are first studied in order to determine damage sensitivity with respect to the mode and frequency of the generated guided wave. The optimal configuration of the system in terms of piezoceramic size, shape and inter-unit spacing is then validated using finite element modeling (FEM) in 3D. Experimental assessment of propagation characteristics is conducted using laser Doppler vibrometer (LDV) in order to justify theoretical and numerical assumptions and pitchcatch measurements are then performed to validate the efficient detection of the damage and accurate estimation of its size. © 2012 IOP Publishing Ltd. | |||||
BibTeX:
@article{Quaegebeur2012, author = {Quaegebeur, N. and Micheau, P. and Masson, P. and Castaings, M.}, title = {Methodology for optimal configuration in structural health monitoring of composite bonded joints}, journal = {Smart Materials and Structures}, year = {2012}, volume = {21}, number = {10}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865956848&doi=10.1088%2f0964-1726%2f21%2f10%2f105001&partnerID=40&md5=880cb36bdaad1c64a065cff604b25d21}, doi = {https://doi.org/10.1088/0964-1726/21/10/105001} } |
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Quaegebeur, N., Micheau, P., Masson, P. and Castaings, M. | SHM system using rectangular versus circular piezoceramic for the inspection within the bond of a composite bonded joint | 2012 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 8348 |
conference | DOI URL |
Abstract: A bonded joint between an aluminum plate and CFRP plate (7 plies) is considered using a titanium spar. The bonding is ensured by double sided adhesive that is prone to degradation with aging structures. The problem is to detect the disbond occurring at the CFRP plate/titanium spar interface using guided waves generated by piezoceramic transducers (PZT) bonded on the CFRP plate. The objective of the present work is to optimize the SHM configuration (PZT location, Lamb wave mode, size and shape of the PZT) for pitch and catch measurements within the bond. 1D, 2D and 3D numerical simulations of the instrumented structure were performed to optimize the SHM configuration. It appears that the rectangular shape can ensure a plane wave front within the bond, since the circular shape generates complex wave fronts. For experimental investigation, coupon structure was manufactured with synthetic damages inserted using two hemispherical Teflon tapes between adhesive and titanium spar. The structure was instrumented for inspection within the bond by using rectangular PZT. Experimental validation of propagation characteristics and damage sensitivity are performed using LDV measurement within the bond line. Damage detectability using rectangular piezoceramics in pitch-catch configuration within the bond is validated. © 2012 SPIE. | |||||
BibTeX:
@conference{Quaegebeur2012, author = {Quaegebeur, N. and Micheau, P. and Masson, P. and Castaings, M.}, title = {SHM system using rectangular versus circular piezoceramic for the inspection within the bond of a composite bonded joint}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2012}, volume = {8348}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861755379&doi=10.1117%2f12.915389&partnerID=40&md5=a3f14205b0655f8d0296a4b54fff9db8}, doi = {https://doi.org/10.1117/12.915389} } |
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Quaegebeur, N. and Masson, P. | Correlation-based imaging technique using ultrasonic transmit-receive array for Non-Destructive Evaluation | 2012 | Ultrasonics Vol. 52(8), pp. 1056-1064 |
article | DOI URL |
Abstract: This paper describes a novel array post-processing method for Non-Destructive Evaluation (NDE) using phased-array ultrasonic probes. The approach uses the capture and processing of the full matrix of all transmit-receive time-domain signals from a transducer array as in the case of the Total Focusing Method (TFM), referred as the standard of imaging algorithms. The proposed technique is based on correlation of measured signals with theoretical propagated signals computed over a given grid of points. In that case, real-time imaging can be simply implemented using discrete signal product. The advantage of the present technique is to take into account transducer directivity, dynamics and complex propagation patterns, such that the number of required array elements for a given imaging performance can be greatly reduced. Numerical and experimental application to contact inspection of isotropic structure is presented and real-time implementation issues are discussed. © 2012 Elsevier B.V. All rights reserved. | |||||
BibTeX:
@article{Quaegebeur20121056, author = {Quaegebeur, N. and Masson, P.}, title = {Correlation-based imaging technique using ultrasonic transmit-receive array for Non-Destructive Evaluation}, journal = {Ultrasonics}, year = {2012}, volume = {52}, number = {8}, pages = {1056-1064}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867688055&doi=10.1016%2fj.ultras.2012.08.017&partnerID=40&md5=1e3998ee162cf538fecdd8599cfbbf85}, doi = {https://doi.org/10.1016/j.ultras.2012.08.017} } |
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Quaegebeur, N., Micheau, P. and Masson, P. | Within-the-bond strategy for in-situ inspection of composite bonded joints using piezoceramics | 2012 | Proceedings of the 6th European Workshop - Structural Health Monitoring 2012, EWSHM 2012 Vol. 1, pp. 277-284 |
conference | URL |
Abstract: In the present study, attention is paid to the implementation of a piezoceramic based structural health monitoring (SHM) system on a composite bonded and riveted lap-joint. The structure is composed of an aluminum plate riveted to a titanium spar which is itself bonded to a CFRP laminate structure. The bonding is ensured by double sided adhesive that is prone to degradation with improper installation or when submitted to extreme strains. Inspection within the bond is proposed in order to avoid complex reflection patterns induced by the rivets and optimal configuration is derived for the specific application. The novelty of the resent approach resides in the development of an optimal SHM configuration for within-the-bond inspection of complex joints in terms of mode, frequency, transducer array configuration and metrics to be monitored. Theoretical propagation and through-the-thickness strain distribution are first studied in order to determine damage sensitivity with respect to mode and frequency of the generated guided wave. It is shown that AO mode appears as the best candidate for generation of large shear strains in the bond line. The optimal configuration of the system in terms of piezoceramic size, shape and inter-unit spacing is then validated using Finite Element Modeling (FEM) in 2D and 3D. The advantages of both approaches are discussed with respect to the bond complexity. Experimental validation of propagation characteristics is conducted using Laser Doppler Vibrometer (LDV) in order to validate theoretical and numerical assumptions and pitch-and-catch measurements are then proposed with rectangular piezoceramics in order to validate the efficient detection of the damage and accurate estimation of its size. It is shown that disbond size from 5mm to 20mm can be accurately determined by measuring AO mode attenuation. | |||||
BibTeX:
@conference{Quaegebeur2012277, author = {Quaegebeur, N. and Micheau, P. and Masson, P.}, title = {Within-the-bond strategy for in-situ inspection of composite bonded joints using piezoceramics}, journal = {Proceedings of the 6th European Workshop - Structural Health Monitoring 2012, EWSHM 2012}, year = {2012}, volume = {1}, pages = {277-284}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894859258&partnerID=40&md5=0527a1813bd9a95c4bea091c482bcb3c} } |
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Quaegebeur, N., Masson, P., Micheau, P. and Mrad, N. | Broadband generation of ultrasonic guided waves using piezoceramics and sub-band decomposition | 2012 | IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control Vol. 59(5), pp. 928-938 |
article | DOI URL |
Abstract: Classically, damage detection or dispersion curve determination using piezoceramic-generated guided waves has been based on analysis of propagation properties of multiple narrowband excitation signals. However, dispersion and multimodal propagation impair the determination of propagation properties. More recently, it has been proposed to consider broadband excitations for both damage imaging and group velocity estimation. Among existing transducer technologies, although laser excitation is prone to practical limitations in terms of dimensions and generated amplitudes, it allows generation of noncontact, point-like broadband displacement. Thus, broadband generation of guided waves using piezoceramics can be envisioned. However, direct impulse response measurements are limited by the generated amplitude, leading to low SNR measurements. For this purpose, chirp excitations have been proposed using variable-frequency bursts, leading to phase and amplitude variations with respect to the frequency, such that this approach is not suitable for precise estimation of time of flight (ToF) or modal amplitude. In this paper, a sub-band decomposition technique that allows high-SNR measurements of impulse response in a given frequency range is proposed. Broadband excitation is decomposed over a given number of frequency sub-bands, generated by a piezoceramic element and measurement is performed using a laser Doppler vibrometer (LDV) or a piezoceramic sensor. Application to experimental estimation of group velocity and damage detection in pitchcatch configuration is proposed. It is shown that the proposed method allows damage estimation without a priori knowledge of the damage size, whereas narrowband techniques can fail at specific wavelengths. © 2012 IEEE. | |||||
BibTeX:
@article{Quaegebeur2012928, author = {Quaegebeur, N. and Masson, P. and Micheau, P. and Mrad, N.}, title = {Broadband generation of ultrasonic guided waves using piezoceramics and sub-band decomposition}, journal = {IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control}, year = {2012}, volume = {59}, number = {5}, pages = {928-938}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861490005&doi=10.1109%2fTUFFC.2012.2277&partnerID=40&md5=defd8f41bc86b8179f45f16752c16eab}, doi = {https://doi.org/10.1109/TUFFC.2012.2277} } |
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Salissou, Y., Panneton, R. and Doutres, O. | Complement to standard method for measuring normal incidence sound transmission loss with three microphones | 2012 | Journal of the Acoustical Society of America Vol. 131(3), pp. EL216-EL222 |
article | DOI URL |
Abstract: Complement to standard E2611-09 of the American Society for Testing and Materials [Standard Test Method for Measurement of Normal Incidence Sound Transmission of Acoustical Materials Based on the Transfer Matrix Method (American Society for Testing and Materials, New York, 2009)] is proposed in order to measure normal incidence sound transmission loss of materials in a modified impedance tube using a three-microphone two-load or one-load method. The modified tube is a standard two-microphone impedance tube, where a third microphone is mounted on a movable hard termination. This method is conceptually identical to the four-microphone two-load or one-load method described in the standard; however, it requires fewer transfer functions and one microphone less. The method is validated on (1) symmetrical homogeneous and (2) non-symmetrical non-homogeneous specimens. © 2012 Acoustical Society of America. | |||||
BibTeX:
@article{Salissou2012, author = {Salissou, Y. and Panneton, R. and Doutres, O.}, title = {Complement to standard method for measuring normal incidence sound transmission loss with three microphones}, journal = {Journal of the Acoustical Society of America}, year = {2012}, volume = {131}, number = {3}, pages = {EL216-EL222}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858982559&doi=10.1121%2f1.3681016&partnerID=40&md5=dba8ee552442af5d04669965a2d820c6}, doi = {https://doi.org/10.1121/1.3681016} } |
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Atalla, N. and Rhazi, D. | Modeling the vibroacoustics response of structures with attached noise control materials | 2011 | ASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011 Vol. 8, pp. 665-671 |
conference | URL |
Abstract: This paper discusses the modeling of the vibration and acoustic response of panels with attached sound packages, using both analytical and numerical methods. Special attention is devoted to the modeling of various types of porous materials (rigid, limp, porous elastic,?) in various mounting conditions (single wall and double wall) together with the calculation of various vibroacoustic indicators (vibration response, radiated power, transmission loss, added damping, air-borne insertion loss, Structure-borne insertion loss?) under various excitations (acoustical, mechanical and Turbulent Boundary Layer). In particular, examples illustrating the practicality and usefulness of these methods are presented. Copyright © 2011 by ASME. | |||||
BibTeX:
@conference{Atalla2011665, author = {Atalla, N. and Rhazi, D.}, title = {Modeling the vibroacoustics response of structures with attached noise control materials}, journal = {ASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011}, year = {2011}, volume = {8}, pages = {665-671}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869166247&partnerID=40&md5=aa174b74ea2a510346d5881b42786d8b} } |
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Avoine, O., Bossé, D., Beaudry, B., Beaulieu, A., Albadine, R., Praud, J.-P., Robert, R., Micheau, P. and Walti, H. | Total liquid ventilation efficacy in an ovine model of severe meconium aspiration syndrome | 2011 | Critical Care Medicine Vol. 39(5), pp. 1097-1103 |
article | DOI URL |
Abstract: OBJECTIVE: To test the hypothesis that total liquid ventilation enables a more effective and better tolerated lavage than a bronchoalveolar lavage performed with diluted surfactant in a newborn ovine model of severe acute meconium aspiration syndrome. DESIGN: Prospective, randomized, interventional study. SETTING: Animal research laboratory at the Faculté de médecine et des sciences de la santé de l'université de Sherbrooke, Sherbrooke, Canada. SUBJECTS: Twenty-three newborn lambs, <4 days, 2.5-4.0 kg in weight. INTERVENTIONS: Animals were intubated, anesthetized, and paralyzed. Catheters were placed in the femoral artery and jugular vein. Severe meconium aspiration syndrome was obtained by instillation of a 25% dilution of human meconium in saline (1 mL/kg × 2). Lambs were then randomized in 12 total liquid ventilation-bronchoalveolar lavage (minute ventilation of 160 mL/kg/min with perfluorodecalin) vs. 11 bronchoalveolar lavage performed with diluted surfactant (conventional ventilation + 30 mL/kg in two aliquots bronchoalveolar lavage with 5 mg/mL BLES surfactant). Surviving lambs were ventilated for a total of 4 hrs and euthanized. MEASUREMENTS AND MAIN RESULTS: Arterial blood gases, systemic and pulmonary hemodynamic parameters using the thermodilution method, percentage of recovered meconium, and lung histologic scores. Total liquid ventilation bronchoalveolar lavage enabled a significantly higher Pao2 throughout the experiment. Paco2, pH, and hemodynamic parameters were comparable for both groups except for an increase in mean pulmonary arterial pressure during total liquid ventilation. Total liquid ventilation bronchoalveolar lavage allowed for 43 ± 14% of the instilled meconium to be removed vs. 28 ± 10% for bronchoalveolar lavage performed with diluted surfactant (p =.022). Lung histologic analysis showed no difference between total scores. CONCLUSIONS: Total liquid ventilation bronchoalveolar lavage is well tolerated and more effective in terms of meconium washout and gas exchange than bronchoalveolar lavage performed with diluted surfactant in this experimental model of severe meconium aspiration syndrome. These positive results open the way to further experiments in our ovine model, ultimately aiming at a clinical trial with total liquid ventilation bronchoalveolar lavage to treat severe meconium aspiration syndrome. Copyright © 2011 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins. | |||||
BibTeX:
@article{Avoine20111097, author = {Avoine, O. and Bossé, D. and Beaudry, B. and Beaulieu, A. and Albadine, R. and Praud, J.-P. and Robert, R. and Micheau, P. and Walti, H.}, title = {Total liquid ventilation efficacy in an ovine model of severe meconium aspiration syndrome}, journal = {Critical Care Medicine}, year = {2011}, volume = {39}, number = {5}, pages = {1097-1103}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955463117&doi=10.1097%2fCCM.0b013e31820ead1a&partnerID=40&md5=dbc260f0a2fae96ea03404b6da8ed1be}, doi = {https://doi.org/10.1097/CCM.0b013e31820ead1a} } |
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Beaulieu, A., Foucault, E., Braud, P., Micheau, P., Szeger, P., Robert, R. and Walti, H. | A flowmeter for unsteady liquid flow measurements in total liquid ventilation | 2011 | MeMeA 2011 - 2011 IEEE International Symposium on Medical Measurements and Applications, Proceedings | conference | DOI URL |
Abstract: A promising alternative to the use of conventional mechanical ventilators to treat pulmonary syndromes such as acute respiratory distress and meconium aspiration consists of employing total liquid ventilators, an experimental device which uses an oxygenated perfluorochemical liquid instead of a gas mixture of air and oxygen. Liquid ventilator development is an active field of research, as most components cannot be directly imported from gas ventilators and must be completely redesigned. The addressed problem is to provide a reliable measurement of the liquid flow in and out of the lungs considering that it must take into account unsteady effects to produce accurate measurements. An unsteady flowmeter was developed for implementation in the Inolivent-4, our total liquid ventilator prototype developed at Université de Sherbrooke. It consists of a symmetrical venturi tube comprising three pressure sensors and in which flow measurement is obtained by numerically solving a slightly modified version of the unsteady Bernoulli equation. A prototype was validated in-vitro by applying zero-mean sinusoidal flows. Low-frequency characterization determined the venturi discharge coefficient as a function of the Reynolds number, and higher-frequency measurements determined the applicable bandwidth of the device. The velocity profiles were measured in the venturi by particle image velocimetry (PIV), and the device was calibrated by comparison with an ultrasonic flowmeter and measurements from a piston pump. Results showed that quasi-steady flows could be accurately measured in the 5 ml/s - 60 ml/s range, while low-amplitude (10 ml/s) oscillatory flows were well measured for frequencies below 3 Hz. Finally, PIV experiments showed that the flat velocity profile assumption required for a simple solution of the flowmeter equation was valid within the operating range. © 2011 IEEE. | |||||
BibTeX:
@conference{Beaulieu2011, author = {Beaulieu, A. and Foucault, E. and Braud, P. and Micheau, P. and Szeger, P. and Robert, R. and Walti, H.}, title = {A flowmeter for unsteady liquid flow measurements in total liquid ventilation}, journal = {MeMeA 2011 - 2011 IEEE International Symposium on Medical Measurements and Applications, Proceedings}, year = {2011}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80052388283&doi=10.1109%2fMeMeA.2011.5966764&partnerID=40&md5=fc73c1c1de42c561f004fc79860a044f}, doi = {https://doi.org/10.1109/MeMeA.2011.5966764} } |
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Beaulieu, A., Foucault, E., Braud, P., Micheau, P. and Szeger, P. | A flowmeter for unsteady liquid flow measurements | 2011 | Flow Measurement and Instrumentation Vol. 22(2), pp. 131-137 |
article | DOI URL |
Abstract: An unsteady flowmeter was developed for implementation in the Inolivent-4 total liquid ventilator prototype. The proposed design consists of a symmetrical venturi tube comprising three pressure sensors and in which flow measurement is obtained by numerically solving a slightly modified version of the unsteady Bernoulli equation. A prototype was validated experimentally by applying zero-mean sinusoidal flows. Low-frequency characterization determined the venturi discharge coefficient as a function of the Reynolds number, and higher-frequency (=4Hz) measurements determined the applicable bandwidth of the device. The velocity profiles were measured in the venturi by particle image velocimetry (PIV), and the device was calibrated experimentally by comparison with an ultrasonic flowmeter and measurements from a piston pump. Results showed that quasi-steady flows could be accurately measured in the 5-60 ml/s range, while low-amplitude (=10ml/s) oscillatory flows were well-measured for frequencies below 3 Hz. Finally, PIV experiments showed that the flat velocity profile assumption required for a simple solution of the flowmeter equation was valid within the operating range. © 2011 Elsevier Ltd. | |||||
BibTeX:
@article{Beaulieu2011131, author = {Beaulieu, A. and Foucault, E. and Braud, P. and Micheau, P. and Szeger, P.}, title = {A flowmeter for unsteady liquid flow measurements}, journal = {Flow Measurement and Instrumentation}, year = {2011}, volume = {22}, number = {2}, pages = {131-137}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952316569&doi=10.1016%2fj.flowmeasinst.2011.01.001&partnerID=40&md5=37f43d55a4723098a48e065456afe786}, doi = {https://doi.org/10.1016/j.flowmeasinst.2011.01.001} } |
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Biboud, J., Panneton, R., Elkoun, S. and Oddo, R. | Assessment of acoustic properties of different recycled polymer-based materials for road work sound barrier walls application | 2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(3), pp. 22-23 |
article | URL |
Abstract: This paper examines environmentally-friendly alternatives for rock and glass wools in sound barrier walls applications. Around road-work construction sites, the most disturbing frequencies are between 500 and 2,000 Hz. Therefore, the materials should be acoustically efficient within this frequency range, and all measurements should be carried out. More interestingly, those 3 materials seem to be better than rock or glass wool as they exhibit higher absorption coefficients. Only material D appears to be less efficient in spite of its larger thickness. This result can be ascribed to a lack of compaction as it has the lowest density among the 4 selected materials. It was shown that, in terms of sound absorption, the selected recycled fiber-polymers seem to be equal or better than rock or glass wool. Due to this encouraging result, acoustic characterization of the recycled material on an experimental on-scale sound barrier wall and modeling are presently in progress. | |||||
BibTeX:
@article{Biboud201122, author = {Biboud, J. and Panneton, R. and Elkoun, S. and Oddo, R.}, title = {Assessment of acoustic properties of different recycled polymer-based materials for road work sound barrier walls application}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {3}, pages = {22-23}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859488700&partnerID=40&md5=d99f566b848484964bf89e8f2fcc9926} } |
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Camier, C., Gauthier, P.-A., Pasco, Y. and Berry, A. | Sound field reproduction applied to flight vehicles sound environments | 2011 | Proceedings of the AES International Conference | conference | URL |
Abstract: This paper proposes a preliminary theoretical study for sound field and sound environment reproduction in ight vehicles. A fully-coupled cavity, cylindrical shell and exterior radiation model approximates an aircraft cabin mock-up. Material and geometry charateristics are inspired by measurements perfomed on a cabin mock-up. The sound field reproduction is based on reproduction error minimization at a microphone array positionned in the cavity. Two reproduction systems, based on actuators or loudspeakers are simulated in order to compare their feasability and performance. The model linking excitator strength with the sound pressure on the spatially extended array region is developped in a matricial form. The promising results obtained in terms of reproduced pressure in the array region in both cases presume the reliability of such dedicated systems. | |||||
BibTeX:
@conference{Camier2011, author = {Camier, C. and Gauthier, P.-A. and Pasco, Y. and Berry, A.}, title = {Sound field reproduction applied to flight vehicles sound environments}, journal = {Proceedings of the AES International Conference}, year = {2011}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953832023&partnerID=40&md5=f7e14430398782f47e184f0f903a1c3b} } |
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Cherif, R., Amedin, C. and Atalla, N. | Application of modal assurance criterion on metallic and composite structures | 2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(3), pp. 216-217 |
article | URL |
Abstract: The article presents the use of the Modal Assurance Criterion (MAC) for the purpose of spatially comparing mode shapes to identify differences in the degrees of freedom between test and analysis modes. In modal analysis, direct use of experimental results may include errors due to measurements limitations, for example modes duplications. Most popular applications of modal testing provide direct comparisons of deformed modal shapes between analytical and experimental findings. The responses of modal testing are measured at a number of sensors, which allow visualization of the measured motion. Before performing any operation to assess the quality of the analytical model, it is paramount that a correspondence be established between the analytical and experimental methods. The MAC methodology was evaluated on simple metallic beams, plates and sandwich-composite panels. MAC was verified on real measured data, which lead to the necessity of this algorithm for real life applications especially for sandwich-composite structures. | |||||
BibTeX:
@article{Cherif2011216, author = {Cherif, R. and Amedin, C.K. and Atalla, N.}, title = {Application of modal assurance criterion on metallic and composite structures}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {3}, pages = {216-217}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859481354&partnerID=40&md5=47b93ba59bdeaf09243b6084b79280d0} } |
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Chevillotte, F. and Panneton, R. | Coupling transfer matrix method to finite element method for analyzing the acoustics of complex hollow body networks | 2011 | Applied Acoustics Vol. 72(12), pp. 962-968 |
article | DOI URL |
Abstract: This paper exposes a procedure to couple multiport transfer matrices to finite elements for analyzing the acoustics of automotive hollow body networks with a minimum of memory requirements and computational time. Generally, hollow body networks are made up from a series of elongated fluid partitions similar to ducts or waveguides. These fluid partitions generally contain complex elements: junctions, noise control elements, and cavities. The location and type of these elements in the network, mainly the noise control elements (e.g., sealing parts), may impact the noise inside a car. In the proposed hybrid method, the elongated fluid partitions are modeled with fluid finite elements. All complexities are modeled with two-port or multiport transfer matrices. The coupling of these matrices to finite elements is naturally done at the weak integral formulation stage of the acoustical problem. The coupling does not add any degrees of freedom to, nor modify, the original finite element matrix system. Consequently, changing locations and types of noise control elements in the hollow body network is fast and does not require rebuilding the finite element system. This enables optimizing the acoustics of a complex network on a desktop computer. The hybrid method is compared to experimental results on a tee-shaped hollow body networks. Good correlations are obtained. © 2011 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Chevillotte2011962, author = {Chevillotte, F. and Panneton, R.}, title = {Coupling transfer matrix method to finite element method for analyzing the acoustics of complex hollow body networks}, journal = {Applied Acoustics}, year = {2011}, volume = {72}, number = {12}, pages = {962-968}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79961031386&doi=10.1016%2fj.apacoust.2011.06.005&partnerID=40&md5=a7e236720468f6a768236be951c33b7d}, doi = {https://doi.org/10.1016/j.apacoust.2011.06.005} } |
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Dhifaoui, H., Atalla, N., Panneton, R. and Meslioui, S.-A. | Nonlinear acoustic properties of perforated liners: New theory and experiment | 2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(4), pp. 54-55 |
article | URL |
Abstract: A new nonlinear impedance model of a micro-perforated panel (MPP) is developed using an equivalent fluid concept, which is relatively easy to integrate into the Transfer Matrix Method (TMM) to predict performance of multiple MPP sound absorbers. The nonlinear model is proposed to change the linear-end correction of the acoustic mass in terms of tortuosity. The proposed nonlinear equivalent tortuosity is given by nonlinear end correction. It is found that the effect of the vibration of the air particles on the baffle in the vicinity of the aperture increases the thermo-viscous frictions. As a first validation of the model, an experimental investigation of the linear and nonlinear impedance of single degree of freedom 1 DOF and 2DOF MMP based liners are used with different type of geometric parameter. A good agreement is found between the model and the experiments for the reactance part. This confirms the correction of the radiation part of the present model. | |||||
BibTeX:
@article{Dhifaoui201154, author = {Dhifaoui, H. and Atalla, N. and Panneton, R. and Meslioui, S.-A.}, title = {Nonlinear acoustic properties of perforated liners: New theory and experiment}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {4}, pages = {54-55}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84855594157&partnerID=40&md5=3d51d0f368b6d488e6b690e259c18adb} } |
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Doutres, O., Atalla, N. and Dong, K. | Effect of the microstructure closed pore content on the acoustic behavior of polyurethane foams | 2011 | Journal of Applied Physics Vol. 110(6) |
article | DOI URL |
Abstract: The present paper proposes to investigate the links between the microstructure of polyurethane foams and their sound absorbing efficiency, and more specifically the effect of membranes closing the cells. This study is based on the complete characterization of 15 polyurethane foam with various cell sizes and reticulation rates (i.e., open pore content): (i) characterization of the microstructure properties (cell size Cs, strut thickness t, reticulation rate Rw ?) from SEM pictures, (ii) characterization of nonacoustic parameters (porosity f, airflow resistivity s, tortuosity a8?) from direct and indirect methods. Existing analytical links between microstructure properties and nonacoustic parameters are first applied to fully reticulated materials. Then, they are improved empirically to account for the presence of the closed pore content. The proposed expressions associated to the Johnson-Champoux-Allard porous model allow a good estimation of the sound absorbing behavior of all polyurethane foams, fully reticulated or not. This paper also demonstrates the important effect of the presence of cell membranes: increase of the airflow resistivity, tortuosity, and the ratio between the thermal and viscous characteristic lengths while decreasing these two characteristic lengths. Thus, the sound absorption efficiency at low frequencies is improved but can be worsened in some higher frequency bands. © 2011 American Institute of Physics. | |||||
BibTeX:
@article{Doutres2011, author = {Doutres, O. and Atalla, N. and Dong, K.}, title = {Effect of the microstructure closed pore content on the acoustic behavior of polyurethane foams}, journal = {Journal of Applied Physics}, year = {2011}, volume = {110}, number = {6}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80053483633&doi=10.1063%2f1.3631021&partnerID=40&md5=9449dff762271810ae310b94ab3ed8c4}, doi = {https://doi.org/10.1063/1.3631021} } |
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Doutres, O. and Atalla, N. | Experimental estimation of the transmission loss contributions of a sound package placed in a double wall structure | 2011 | Applied Acoustics Vol. 72(6), pp. 372-379 |
article | DOI URL |
Abstract: The objective of this paper is to propose a practical impedance tube method to optimize the sound transmission loss of double wall structure by concentrating on the sound package placed inside the structure. In a previous work, the authors derived an expression that breakdown the transmission loss of a double wall structure containing a sound absorbing blanket separated from the panels by air layers in terms of three main contributions; (i) sound transmission loss of the panels, (ii) sound transmission loss of the blanket and (iii) sound absorption due to multiple reflections inside the cavity. The sound transmission loss contributions of the blanket can thus be estimated from three acoustic measurements using impedance tube techniques: two reflection coefficients at the front face and the rear face of the blanket placed in specific positions characteristic of its position inside the double wall structure and its sound transmission coefficient. The method is first validated in the case of a double wall structure filled with a 2 in. foam material. Next, it is applied to investigate (i) the effect of frame compression of a 2 in. fibre glass in an aeronautic-type double wall structure and (ii) the effect of double porosity with or without porous inclusions in a building-type double wall structure. © 2010 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Doutres2011372, author = {Doutres, O. and Atalla, N.}, title = {Experimental estimation of the transmission loss contributions of a sound package placed in a double wall structure}, journal = {Applied Acoustics}, year = {2011}, volume = {72}, number = {6}, pages = {372-379}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79951722125&doi=10.1016%2fj.apacoust.2010.12.011&partnerID=40&md5=f1959645998c441082babf75d5610a51}, doi = {https://doi.org/10.1016/j.apacoust.2010.12.011} } |
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Dupont, T., Leclaire, P., Sicot, O., Gong, X. and Panneton, R. | Acoustic properties of air-saturated porous materials containing dead-end porosity | 2011 | Journal of Applied Physics Vol. 110(9) |
article | DOI URL |
Abstract: This study examines the acoustic properties of materials with complex micro-geometry containing partially open or dead-end (DE) porosity. One of these kinds of materials can be obtained from dissolving salt grains embedded in a solid metal matrix with the help of water. The solid matrix is obtained after the metal, in liquid form, has invaded the granular material formed by the salt particles at negative pressure and high temperature, and after cooling and solidification of the metal. Comparisons between theoretical and experimental results show that the classical Johnson-Champoux-Allard model does not quite accurately predict the acoustic behavior. These results suggest that the assumptions of the Biot theory may not all be fulfilled and that cavity resonators and dead ends can be present in the material. The first part of the study proposes a simple model to account for this geometry. Based upon this model, two acoustic transfer matrices are developed: one for non-symmetric and one for symmetric dead-end porous elements. It is thought that this model can be used to study the acoustic absorption and sound transmission properties of the type of material previously described. In the second part, a series of simplified samples are proposed and tested with a three-microphone impedance tube to validate the exposed model. Finally, the third part compares the predictions of the exposed model to the impedance tube results on a real aluminum foam sample containing dead-end pores. These first results are encouraging and show that this simple model also provides a good prediction for these materials with more complicated microstructure. © 2011 American Institute of Physics. | |||||
BibTeX:
@article{Dupont2011, author = {Dupont, T. and Leclaire, P. and Sicot, O. and Gong, X.L. and Panneton, R.}, title = {Acoustic properties of air-saturated porous materials containing dead-end porosity}, journal = {Journal of Applied Physics}, year = {2011}, volume = {110}, number = {9}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-81355142765&doi=10.1063%2f1.3646556&partnerID=40&md5=cc4c06f76970f0aaa1651b859920b22c}, doi = {https://doi.org/10.1063/1.3646556} } |
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Gauthier, P.-A., Camier, C., Pasco, Y., Chambatte, E. and Berry, A. | Sound field extrapolation: Inverse problems, virtual microphone arrays and spatial filters | 2011 | Proceedings of the AES International Conference | conference | URL |
Abstract: Sound field extrapolation is useful for measurement, description and characterization of sound environments and sound fields that must be reproduced using spatial sound system such as Wave Field Synthesis, Ambisonics, etc. In this paper, two methods are compared: inverse problems and virtual microphone arrays with filtering in the cylindrical harmonics domain. The goal was to define and identify methods that could accommodate to various non-uniform sensor arrays (i.e. non array-specific methods) and that are less sensitive to measurement noise. According to the results presented in this paper, it seems that the method based on inverse problem with Tikhonov regularization is less sensitive to measurement noise. | |||||
BibTeX:
@conference{Gauthier2011, author = {Gauthier, P.-A. and Camier, C. and Pasco, Y. and Chambatte, E. and Berry, A.}, title = {Sound field extrapolation: Inverse problems, virtual microphone arrays and spatial filters}, journal = {Proceedings of the AES International Conference}, year = {2011}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953833788&partnerID=40&md5=dad736d080317111065a0cf0a0ef416d} } |
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Gauthier, P.-A., Chambatte, E., Camier, C., Pasco, Y. and Berry, A. | Beamforming regularization, scaling matrices and inverse problems for sound field extrapolation and characterization: Part II - Experiments | 2011 | 131st Audio Engineering Society Convention 2011 Vol. 1, pp. 119-138 |
conference | URL |
Abstract: Sound field extrapolation (SFE) is aimed at the prediction of a sound field in an extrapolation region using microphone array. For sound environment reproduction purposes, sound field characterization (SFC) aims at a more generic or parametric description of a measured or extrapolated sound field using different physical or subjective metrics. In this paper, experiments with a recently-developed SFE method (Part I - Theory) are reported in a first instance. The method is based on an inverse problem formulation combined with a recently proposed regularization approach: a beamforming matrix in the discrete smoothing norm of the cost function. In a second instance, the results obtained from the SFE method are applied to SFC as presented in Part I. The SFC classification method is verified in two environments that recreate ideal or complex sound fields. In light of the presented results and discussion, it is argued that SFE and SFC proposed methods are effective. | |||||
BibTeX:
@conference{Gauthier2011119, author = {Gauthier, P.-A. and Chambatte, E. and Camier, C. and Pasco, Y. and Berry, A.}, title = {Beamforming regularization, scaling matrices and inverse problems for sound field extrapolation and characterization: Part II - Experiments}, journal = {131st Audio Engineering Society Convention 2011}, year = {2011}, volume = {1}, pages = {119-138}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866307885&partnerID=40&md5=c6d1a56efd864bb3f088c926a1ee8aea} } |
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Gauthier, J.-P., Micheau, P., Cauet, S., Coirault, P. and Martin, P. | Extremal harmonic active control of power for a monocylinder hybrid powertrain | 2011 | Journal of Sound and Vibration Vol. 330(24), pp. 5785-5790 |
article | DOI URL |
Abstract: This article presents a real-life application for the extremal harmonic active control of power [1] applied on a hybrid engine setup. The active control was adapted for a hybrid powertrain constituted of a one-cylinder diesel engine coupled with a permanent magnet synchronous machine. The problem was formulated in the harmonic domain and the control objective was to extremalize energetic criterions. Three criterions were considered: minimizing the speed ripple of the engine, maximizing the mechanical reactive power (mechanical impedance adaptation) and maximizing the active electric power for energy harvesting. The results show that, for the first and second orders of the ripple, speed oscillations can be completely cancelled and reactive power and active power can be optimized on-line. The implicit extremal controller converged rapidly, remaining stable even when the mean engine speed changed abruptly. These results confirm the robustness and the applicability of the extremal harmonic active control for industrial applications. © 2011 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Gauthier20115785, author = {Gauthier, J.-P. and Micheau, P. and Cauet, S. and Coirault, P. and Martin, P.}, title = {Extremal harmonic active control of power for a monocylinder hybrid powertrain}, journal = {Journal of Sound and Vibration}, year = {2011}, volume = {330}, number = {24}, pages = {5785-5790}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80052264597&doi=10.1016%2fj.jsv.2011.07.007&partnerID=40&md5=455c127b3ab8044f8be830846f0cb72d}, doi = {https://doi.org/10.1016/j.jsv.2011.07.007} } |
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Gauthier, P.-A., Camier, C., Pasco, Y., Berry, A., Chambatte, E., Lapointe, R. and Delalay, M.-A. | Beamforming regularization matrix and inverse problems applied to sound field measurement and extrapolation using microphone array | 2011 | Journal of Sound and Vibration Vol. 330(24), pp. 5852-5877 |
article | DOI URL |
Abstract: For sound field reproduction using multichannel spatial sound systems such as Wave Field Synthesis and Ambisonics, sound field extrapolation is a useful tool for the measurement, description and characterization of a sound environment to be reproduced in a listening area. In this paper, the inverse problem theory is adapted to sound field extrapolation around a microphone array for further spatial sound and sound environment reproduction. A general review of inverse problem theory and analysis tools is given and used for the comparative evaluation of various microphone array configurations. Classical direct regularization methods such as truncated singular value decomposition and Tikhonov regularization are recalled. On the basis of the reviewed background, a new regularization method adapted to the problem at hand is introduced. This method involves the use of an a priori beamforming measurement to define a data-dependent discrete smoothing norm for the regularization of the inverse problem. This method which represents the main contribution of this paper shows promising results and opens new research avenues. © 2011 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Gauthier20115852, author = {Gauthier, P.-A. and Camier, C. and Pasco, Y. and Berry, A. and Chambatte, E. and Lapointe, R. and Delalay, M.-A.}, title = {Beamforming regularization matrix and inverse problems applied to sound field measurement and extrapolation using microphone array}, journal = {Journal of Sound and Vibration}, year = {2011}, volume = {330}, number = {24}, pages = {5852-5877}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-81155161871&doi=10.1016%2fj.jsv.2011.07.022&partnerID=40&md5=74e21cd4b872ca36ca77dbd80912c141}, doi = {https://doi.org/10.1016/j.jsv.2011.07.022} } |
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Gauthier, P.-A., Chambatte, E., Camier, C., Pasco, Y. and Berry, A. | Beamforming regularization, scaling matrices and inverse problems for sound field extrapolation and characterization: Part I - Theory | 2011 | 131st Audio Engineering Society Convention 2011 Vol. 1, pp. 87-118 |
conference | URL |
Abstract: Sound field extrapolation (SFE) is aimed at the prediction of a sound field in an extrapolation region using a microphone array in a measurement region. For sound environment reproduction purposes, sound field characterization (SFC) aims at a more generic or parametric description of a measured or extrapolated sound field using different physical or subjective metrics. In this paper, a SFE method recently introduced is presented and further developed. The method is based on an inverse problem formulation combined with a beamforming matrix in the discrete smoothing norm of the cost function. The results obtained from the SFE method are applied to SFC for subsequent sound environment reproduction. A set of classification criteria is proposed to distinguish simple types of sound fields on the basis of two simple scalar metrics. A companion paper presents the experimental verifications of the theory presented in this paper. | |||||
BibTeX:
@conference{Gauthier201187, author = {Gauthier, P.-A. and Chambatte, E. and Camier, C. and Pasco, Y. and Berry, A.}, title = {Beamforming regularization, scaling matrices and inverse problems for sound field extrapolation and characterization: Part I - Theory}, journal = {131st Audio Engineering Society Convention 2011}, year = {2011}, volume = {1}, pages = {87-118}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866314271&partnerID=40&md5=937bc9535184dd5cf3be7229385dc82c} } |
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Ghinet, S. and Atalla, N. | Modeling thick composite laminate and sandwich structures with linear viscoelastic damping | 2011 | Computers and Structures Vol. 89(15-16), pp. 1547-1561 |
article | DOI URL |
Abstract: The paper describes the modeling of thick composite laminate and sandwich plates and beams with linear viscoelastic treatments. A discrete laminate model (DLM) is described, validated and compared to numerical spectral finite elements method (SFEM), finite element method (FEM) and experimental results. The DLM approach assumes each layer as thick laminate with orthotropic orientation, rotational inertia and transversal shearing, membrane and bending deformations. First order shear deformation theory is used. The equation of motion is developed following a wave approach based on discrete layer description. It handles symmetrical and asymmetrical layouts of unlimited number of transversal incompressible layers. Next, dilatational (symmetric mode) motion along the core's thickness is considered to complete the DLM solution when applied to the case of symmetric sandwich structures with soft and thick core. The model is compared to a second approach employing spectral finite elements. The latter handles composite laminated plates and beams with orthotropic orientation. It is shown that both approaches estimate accurately the propagating wave solutions of laminated structures. Using these solutions, the input mobility and the mechanical impedance are computed. The two models are successfully compared to classical finite elements as well as to experimental results for different boundary conditions. Moreover, the equivalent damping loss factor of composite laminate plates with viscoelastic treatment is addressed and the influence of the heading direction is discussed. © 2011 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Ghinet20111547, author = {Ghinet, S. and Atalla, N.}, title = {Modeling thick composite laminate and sandwich structures with linear viscoelastic damping}, journal = {Computers and Structures}, year = {2011}, volume = {89}, number = {15-16}, pages = {1547-1561}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79958138958&doi=10.1016%2fj.compstruc.2010.09.008&partnerID=40&md5=86e7f64c6e350539ab8a069104ca10b6}, doi = {https://doi.org/10.1016/j.compstruc.2010.09.008} } |
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Khatami, I. and Berry, A. | Source localization of aircraft engines with circular microphone arrays | 2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(3), pp. 28-29 |
article | URL |
Abstract: Turbo-engines are an important of exterior noise of jet aircraft. Many researchers have attempted to develop methods to identify and locate the various noise sources of aero-engines. The general idea of these approaches is to improve the performance of beamforming by estimating the assigned distribution of sources through the solution of an inverse problem. The goal of this research is the discrimination of inlet and exhaust sources in aircraft engines using far field microphone arrays. The proposed acoustic source identification method in this study is based on a combination of inverse modeling and conventional beamforming. A laboratory test set-up was designed to validate the source identification approach. A small-scale replica of a free field static engine test was installed in a hemi-anechoïc chamber. The results of experimental data show that the Hybrid method is an effective technique for discrimination of inlet and exhaust noise in aero-engines. | |||||
BibTeX:
@article{Khatami201128, author = {Khatami, I. and Berry, A.}, title = {Source localization of aircraft engines with circular microphone arrays}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {3}, pages = {28-29}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859511887&partnerID=40&md5=bf37f108893a33befc57bef7292aa3df} } |
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Kundu, A. and Berry, A. | Active sound control with smart foams using piezoelectric sensoriactuator | 2011 | Journal of Intelligent Material Systems and Structures Vol. 22(16), pp. 1771-1787 |
article | DOI URL |
Abstract: Smart foam offers a lightweight, efficient noise control solution by combining the complimentary advantages of passive dissipation in the foam material with the actuation authority of the active piezoelectric component, under appropriate control input. This study aims to implement the sensoriactuator operation of the active piezoelectric component to obtain an alternate error signal from its mechanical strain response. This can potentially replace the use of far-field microphone error sensors in active noise control applications, and hence improve the compactness of the system. The piezoelectric sensoriactuator has been implemented with the hybrid analog-digital compensation of the quasi-stable feedthrough capacitance of the actuator using an adaptive algorithm. The mechanical charge response, thus obtained, has been minimized using an adaptive algorithm and its effect on the transmission loss has been studied. Additionally, it has also been utilized in absorption and transmission control problems, using a virtual sensing strategy, with the aim of obtaining the desired control performance by minimizing an estimated virtual error signal. The experimental results are supplemented with finite element simulation of the coupled noise control system, and it provides a significant insight into the physical problem of the realization of the smart foam sensoriactuator. © The Author(s) 2011 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav. | |||||
BibTeX:
@article{Kundu20111771, author = {Kundu, A. and Berry, A.}, title = {Active sound control with smart foams using piezoelectric sensoriactuator}, journal = {Journal of Intelligent Material Systems and Structures}, year = {2011}, volume = {22}, number = {16}, pages = {1771-1787}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-82955213618&doi=10.1177%2f1045389X11409079&partnerID=40&md5=424430c0a34324c5e8e746e805392fc4}, doi = {https://doi.org/10.1177/1045389X11409079} } |
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Kundu, A. and Berry, A. | Active control of transmission loss with smart foams | 2011 | Journal of the Acoustical Society of America Vol. 129(2), pp. 726-740 |
article | DOI URL |
Abstract: Smart foams combine the complimentary advantages of passive foam material and spatially distributed piezoelectric actuator embedded in it for active noise control applications. In this paper, the problem of improving the transmission loss of smart foams using active control strategies has been investigated both numerically and experimentally inside a waveguide under the condition of plane wave propagation. The finite element simulation of a coupled noise control system has been undertaken with three different smart foam designs and their effectiveness in canceling the transmitted wave downstream of the smart foam have been studied. The simulation results provide insight into the physical phenomenon of active noise cancellation and explain the impact of the smart foam designs on the optimal active control results. Experimental studies aimed at implementing the real-time control for transmission loss optimization have been performed using the classical single input/single output filtered-reference least mean squares algorithm. The active control results with broadband and single frequency primary source inputs demonstrate a good improvement in the transmission loss of the smart foams. The study gives a comparative description of the transmission and absorption control problems in light of the modification of the vibration response of the piezoelectric actuator under active control. © 2011 Acoustical Society of America. | |||||
BibTeX:
@article{Kundu2011726, author = {Kundu, A. and Berry, A.}, title = {Active control of transmission loss with smart foams}, journal = {Journal of the Acoustical Society of America}, year = {2011}, volume = {129}, number = {2}, pages = {726-740}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952161670&doi=10.1121%2f1.3519676&partnerID=40&md5=ebc4ed532eb29051eb71f1e61ed1e47e}, doi = {https://doi.org/10.1121/1.3519676} } |
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Langlois, J., Verron, C., Gauthier, P.-A. and Guastavino, C. | Perceptual evaluation of interior aircraft sound models | 2011 | IEEE Workshop on Applications of Signal Processing to Audio and Acoustics, pp. 77-80 | conference | DOI URL |
Abstract: We report a listening test conducted to investigate the validity of sinusoids+noise synthesis models for interior aircraft sounds. Two models were evaluated, one for monaural signals and the other for binaural signals. A parameter common to both models is the size of the analysis/synthesis window. This size determines the computation cost and the time/frequency resolution of the synthesis. To evaluate the perceptual impact of reducing the window size, we varied systematically the size N s of the analysis/synthesis window. We used three reference sounds corresponding to three different rows. Twenty-two participants completed an ABX discrimination task comparing original recorded sounds to various resynthesized versions. The results highlight a better discrimination between resynthesized sounds and original recorded sounds for the monaural model than for the binaural model and for a window size of 128 samples than for larger window sizes. We also observed a significant effect of row on discrimination. An analysis/synthesis window size N s of 1024 samples seems to be sufficient to synthesize binaural sounds which are indistinguishable from original sounds; but for monaural sounds, a window size of 2048 samples is needed to resynthesize original sounds with no perceptible difference. © 2011 IEEE. | |||||
BibTeX:
@conference{Langlois201177, author = {Langlois, J. and Verron, C. and Gauthier, P.-A. and Guastavino, C.}, title = {Perceptual evaluation of interior aircraft sound models}, journal = {IEEE Workshop on Applications of Signal Processing to Audio and Acoustics}, year = {2011}, pages = {77-80}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-83455255670&doi=10.1109%2fASPAA.2011.6082339&partnerID=40&md5=3d4fe8f80a900556ca4817555a66cbbd}, doi = {https://doi.org/10.1109/ASPAA.2011.6082339} } |
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Legault, J. and Atalla, N. | The impact of finite dimensions on the vibro-acoustic response of stiffened panels | 2011 | 18th International Congress on Sound and Vibration 2011, ICSV 2011 Vol. 4, pp. 3164-3171 |
conference | URL |
Abstract: This paper presents parameter studies on the impact of finite dimensions on the vibroacoustic response of orthogonally stiffened panels. Various types of loadings are considered (acoustical plane wave, point force, turbulent boundary layer), and the effects of two key parameters are studied: the size of the panel and the level of structural damping. In each case, a spatially windowed periodic model is compared with a Rayleigh-Ritz modal-based model. The latter model accounts for the reflected wave field generated at the boundaries by assuming that the panel is simply supported. In contrast, the windowed periodic model only accounts for finiteness on sound radiation (an infinite approximation is used to calculate the panel response). Numerical studies show that when the wavelength becomes comparable or smaller than the stiffener spacing, the periodic model will be able to reproduce the results obtained with the Rayleigh-Ritz model even for panels with a low number of periodic bays and a low level of structural damping. | |||||
BibTeX:
@conference{Legault20113164, author = {Legault, J. and Atalla, N.}, title = {The impact of finite dimensions on the vibro-acoustic response of stiffened panels}, journal = {18th International Congress on Sound and Vibration 2011, ICSV 2011}, year = {2011}, volume = {4}, pages = {3164-3171}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871525445&partnerID=40&md5=e206345afc27f76f24a79e38d624662b} } |
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Legault, J., Mejdi, A. and Atalla, N. | Vibro-acoustic response of orthogonally stiffened panels: The effects of finite dimensions | 2011 | Journal of Sound and Vibration Vol. 330(24), pp. 5928-5948 |
article | DOI URL |
Abstract: This paper investigates the effects of finite dimensions on the vibro-acoustic response of orthogonally stiffened panels. Three types of excitations are considered: acoustical excitation, point force excitation and random excitation by a turbulent boundary layer. In each case, a spatially windowed periodic model is compared with a RayleighRitz model where the modes of the un-stiffened panel are used as the basis functions. The latter model accounts for the reflected wave field generated at the boundaries by assuming that the panel is simply supported. On the contrary, the windowed periodic model only accounts for finiteness on sound radiation (the assumption of an infinite periodic structure is used to calculate the panel response). Numerical studies show that when the bending wavelength becomes comparable or smaller than the stiffener spacing, the periodic model is able to reproduce the results obtained with the RayleighRitz model. To complement the study, the developed models are compared with numerical simulations (finite element method) and with experimental results. © 2011 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Legault20115928, author = {Legault, J. and Mejdi, A. and Atalla, N.}, title = {Vibro-acoustic response of orthogonally stiffened panels: The effects of finite dimensions}, journal = {Journal of Sound and Vibration}, year = {2011}, volume = {330}, number = {24}, pages = {5928-5948}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-81155161873&doi=10.1016%2fj.jsv.2011.07.017&partnerID=40&md5=d4af61d8c36258a3ad31f219d5c37b7b}, doi = {https://doi.org/10.1016/j.jsv.2011.07.017} } |
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Lépine, J., Champoux, Y. and Drouet, J.-M. | Excitation techniques for testing bike vibration transmission in the laboratory | 2011 | Conference Proceedings of the Society for Experimental Mechanics Series Vol. 6, pp. 35-43 |
conference | URL |
Abstract: Vibrations generated by road surface defects are a significant source of discomfort for cyclists. This paper presents two very different laboratory techniques for studying road bike vibration. The first technique uses a treadmill with a modified belt surface. The second technique is based on the use of a road simulator that was developed specifically to generate displacement excitation under the wheels of the bike. Broadband excitation generated by coarse pavement surface is also evaluated in this study. The objective of this paper is to evaluate and compare the relative merits of these two approaches. For the purposes of evaluation, we have described a technique to obtain a realistic measurement of input in real road conditions. Our results demonstrate that the road simulator succeeds in producing adequate displacement profiles in the vertical axis resulting in a vibration frequency spectrum that closely resembles the measurements in real road conditions. Limitations in current actuator capacity prevent to reproduce very coarse road conditions. Finally, more work is needed to develop an appropriate belt surface that can generate sufficient energy excitation above the 25 Hz range. | |||||
BibTeX:
@conference{Lépine201135, author = {Lépine, J. and Champoux, Y. and Drouet, J.-M.}, title = {Excitation techniques for testing bike vibration transmission in the laboratory}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2011}, volume = {6}, pages = {35-43}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79958113218&partnerID=40&md5=e8be182a4814e560d67091bb4cc566cb} } |
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Leroy, P., Berry, A., Herzog, P. and Atalla, N. | Experimental study of a smart foam sound absorber | 2011 | Journal of the Acoustical Society of America Vol. 129(1), pp. 154-164 |
article | DOI URL |
Abstract: This article presents the experimental implementation and results of a hybrid passive/active absorber (smart foam) made up from the combination of a passive absorbent (foam) and a curved polyvinylidene fluoride (PVDF) film actuator bonded to the rear surface of the foam. Various smart foam prototypes were built and tested in active absorption experiments conducted in an impedance tube under plane wave propagation condition at frequencies between 100 and 1500 Hz. Three control cases were tested. The first case used a fixed controller derived in the frequency domain from estimations of the primary disturbance at a directive microphone position in the tube and the transfer function between the control PVDF and the directive microphone. The two other cases used an adaptive time-domain feedforward controller to absorb either a single-frequency incident wave or a broadband incident wave. The non-linearity of the smart foams and the causality constraint were identified to be important factors influencing active control performance. The effectiveness of the various smart foam prototypes is discussed in terms of the active and passive absorption coefficients as well as the control voltage of the PVDF actuator normalized by the incident sound pressure. © 2011 Acoustical Society of America. | |||||
BibTeX:
@article{Leroy2011154, author = {Leroy, P. and Berry, A. and Herzog, P. and Atalla, N.}, title = {Experimental study of a smart foam sound absorber}, journal = {Journal of the Acoustical Society of America}, year = {2011}, volume = {129}, number = {1}, pages = {154-164}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79551672472&doi=10.1121%2f1.3514502&partnerID=40&md5=7d190540bde320f54ff89e2450128135}, doi = {https://doi.org/10.1121/1.3514502} } |
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Magne, S., Moreau, S., Berry, A. and Sanjose, M. | Aeroacoustic prediction of an automotive cooling fan | 2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(3), pp. 32-33 |
article | URL |
Abstract: The acoustic radiation is computed by a Ffowcs-Williams and Hawkings analogy based on the near field fluctuations provided by the aerodynamic simulation. Considering the Mach numbers at the blade tip, only the thickness noise and the loading noise are computed and the effects of the quadmpole noise are neglected. Only 3 blade passage periods were recorded for the purpose of this paper. Although this short duration cannot yet yield well resolved tones, it shows the correct trend. The sound pressure level at each microphone shows a dipole-like directivity with a maximum on the rotor axis. The results for both meshes confirm the predicted tone at the frequency of the impact between the tip recirculation structure and the blades (600 Hz). Aerodynamic simulation of an automotive fan has been successfully achieved. This computation has highlighted the dominant flow structures that are the dominant sources of unsteadiness on the rotor surfaces and therefore the major sources of noise. | |||||
BibTeX:
@article{Magne201132, author = {Magne, S. and Moreau, S. and Berry, A. and Sanjose, M.}, title = {Aeroacoustic prediction of an automotive cooling fan}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {3}, pages = {32-33}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859501112&partnerID=40&md5=119283fed6b3e7fdf8c45630de7ddb00} } |
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Manning, J. and Panneton, R. | Acoustic model for shoddy-based fibre absorbers | 2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(3), pp. 18-19 |
article | URL |
Abstract: The acoustic behavior of shoddies is not well understood when compared to more ubiquitous porous materials such as fiberglass and certain polymeric foams. Designers must therefore rely on predictive models that are either highly complex or simpler models developed for different materials. The effect can be mitigated by using a larger test sample, however, these tests are more expensive and labor intensive. The second pronounced effect is a microscopic one. Raw shoddy contains a haphazard mix of different fiber types and sizes and characterizing the microstructure for use in predictive models is difficult. The model exchanges a minor loss in precision for this simplification. Charts of the characteristic lengths and static thermal permeability have been omitted for brevity. The behavior of the characteristic lengths is such that individual expressions relating the characteristic lengths to bulk density for each material type are chosen in favor of general expressions. | |||||
BibTeX:
@article{Manning201118, author = {Manning, J. and Panneton, R.}, title = {Acoustic model for shoddy-based fibre absorbers}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {3}, pages = {18-19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859489953&partnerID=40&md5=946419469682ee169cc7c7a94c815c29} } |
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Masson, P., Quaegebeur, N. and Demers, D. | A novel imaging technique for structural health monitoring using sparse and compact arrays | 2011 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 7984 |
conference | DOI URL |
Abstract: In the present paper, a technique called Excitelet is presented for the imaging of damages in thin-walled structures using the correlation of the measured signals with dispersed versions of the excitation signal. Piezoceramic (PZT) actuators are used to generate burst Lamb waves which interact with defects in metallic structures and the measurement is taken using sparse and compact array configurations of PZT sensors. The sparse sensing configuration consists of individual circular PZT elements distributed over the plate while the compact array configuration consists of a linear arrangement of sensors micro-machined on a single piece of bulk PZT wafer. This approach is presented as an extension of the classical imaging techniques and takes advantage of the chirplet-based matching pursuit algorithm. The approach is investigated experimentally on a 1.54 mm thick aluminum plate and comparison with existing Embedded Ultrasonic Structural Radar (EUSR) algorithm is performed for A0 and S0 modes for two frequency ranges of interest (centered at 150 kHz and 550 kHz). Damages are simulated using stacked magnets at different locations on the plate. Significant improvement of imaging quality is demonstrated with respect to existing imaging techniques based on group velocity and Time-of-Flight (ToF), for both sparse and compact PZT array configurations. Multimodal imaging strategies are presented to improve the imaging results. Moreover, it is shown that the proposed imaging technique provide accurate results in the case of dispersive propagation, while existing imaging techniques are no longer applicable. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE). | |||||
BibTeX:
@conference{Masson2011, author = {Masson, P. and Quaegebeur, N. and Demers, D.L.}, title = {A novel imaging technique for structural health monitoring using sparse and compact arrays}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2011}, volume = {7984}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79956195553&doi=10.1117%2f12.880662&partnerID=40&md5=e30a9c6cc12c099690a89c6caaae04a1}, doi = {https://doi.org/10.1117/12.880662} } |
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Mohamed, R., Demers, D. and Masson, P. | A parametric study of piezoceramic thickness effect on the generation of fundamental Lamb modes | 2011 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 7984 |
conference | DOI URL |
Abstract: Ultrasound damage detection using built-in piezoelectric transducers is a promising technique because it can automatically inspect and interrogate structural damage in hard to access areas. Although numerous efforts have been devoted to the application of the structural health monitoring (SHM) concepts to real world problems; there is a shortage in the modeling tools specifically tailored for rapid computer aided design of SHM applications. This is due to the fact that the finite element method, which is the dominant method in the simulation of the wave propagation problems due to its geometric versatility and the capability to simulate complex boundary conditions as well as coupling effects, lacks the required computational efficiency for the structural health monitoring applications. This is because of the high frequencies usually utilized is SHM, posing a huge burden on the mesh size to minimize the errors. Spectral element method (SEM), a variant of the p/FEM, combines the fast convergence rates associated with the spectral methods with the geometric flexibility of the finite element method, thus allowing for more computationally efficient simulation, leading to fast product design cycle. Recently, these advantages have drawn the attention of the different researchers in the field of the SHM. The advantage of the SEM as a high accuracy solution method enables the refinement and the testing of different concepts of SHM. One of these concepts is the main focus of the current paper. The presented work is a parametric study of the effect of the piezoceramic actuator thickness on the fundamental Lamb waves S0, and A0 using a tailored SEM solver. In order to illustrate the reduction of the computational costs the running times of the SEM solver were compared with the running times for some of cases solved using commercial FEM solver (ANSYS), as well as the results are compared with analytical results based on a widely accepted model from the literature. Additionally, the cases were validated experimentally, showing a good agreement with the simulation results. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE). | |||||
BibTeX:
@conference{Mohamed2011, author = {Mohamed, R. and Demers, D.L. and Masson, P.}, title = {A parametric study of piezoceramic thickness effect on the generation of fundamental Lamb modes}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2011}, volume = {7984}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79956221215&doi=10.1117%2f12.880616&partnerID=40&md5=a136bf9fba56c24e5a18b462defb2a3e}, doi = {https://doi.org/10.1117/12.880616} } |
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Mohamed, R. and Masson, P. | A time domain spectral element for coupled piezoelectric actuator/sensor with complex thin-walled assembly structures | 2011 | Structural Health Monitoring 2011: Condition-Based Maintenance and Intelligent Structures - Proceedings of the 8th International Workshop on Structural Health Monitoring Vol. 1, pp. 947-954 |
conference | URL |
Abstract: Characterised by geometrical flexibility, and robustness with respect to realistic conditions modelling such as non-uniform damping, the finite element method (FEM) has dominated the field of numerical simulation of wave propagation phenomena. The main challenge in wide adoption of FEM in numerical simulation of SHM systems based on GW propagation is the prohibitive computational requirements. This paper presents a structured mesh approach with nonequal number of nodes along the element edges, in order to optimize the use of an efficient variant of FEM, spectral element method (SEM) to model relatively complex thin-walled assembly structures. As low as three nodes per thickness can be used, while using a larger number of nodes in the length direction of a two dimensional structure. The presented approach does not require a modification in the element integration, thus preserving the spectral convergence rate of the method. For the modelling of the coupling between the piezoceramic element and the structure, the proposed approach implements mixed implicit/explicit time integration. The propagation of GW has been simulated using ANSYS as a representative of the FEM, compared with experimental measurements and with the results of an in-house developed code implementing the proposed optimized spectral element. The results presented as a comparison of the computational requirements and accuracy for both FEM and SEM, show a higher efficiency for the SEM for the same accuracy. | |||||
BibTeX:
@conference{Mohamed2011947, author = {Mohamed, R. and Masson, P.}, title = {A time domain spectral element for coupled piezoelectric actuator/sensor with complex thin-walled assembly structures}, journal = {Structural Health Monitoring 2011: Condition-Based Maintenance and Intelligent Structures - Proceedings of the 8th International Workshop on Structural Health Monitoring}, year = {2011}, volume = {1}, pages = {947-954}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866639540&partnerID=40&md5=c5e235cd94430d82eeff8ea0b54a9f7b} } |
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Mosanenzadeh, S., Lee, W., Naguib, H., Park, C. and Atalla, N. | Effect of water soluble polymer on acoustic performance of environmentally friendly acoustic foams | 2011 | FOAMS 2011 - 9th International Conference on Foam Processing and Technology | conference | URL |
Abstract: In this study, a highly porous and interconnected foam structures was fabricated using compression molding combined with particulate leaching technique. The produced foams have the potential to act as acoustic absorbers in many applications such as automotive, aerospace and building industries. The foamed structures were fabricated with Polylactide (PLA) and Polyethylene glycol (PEG) with salt as the particulate. The pore size of the foam structure is controlled by salt particulates and higher interconnectivity is achieved by the co-continuous blending morphology of PLA matrix with water-soluble PEG. PLA is a biodegradable thermoplastic polymer and is derived from renewable resources, such as corn starch or sugarcanes. Therefore, the resulting acoustic foams are benign and environmentally friendly. Fabricated foams were characterized for cellular, acoustic and mechanical properties. The acoustic performance of the foams was studied by measuring the normal incident absorption coefficient in accordance with the ASTM E1050 standard. Through this research, high open porosities were achieved and the effect of water soluble polymer on cellular properties and acoustic and mechanical performance of the foams is studied. | |||||
BibTeX:
@conference{Mosanenzadeh2011, author = {Mosanenzadeh, S.G. and Lee, W. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {Effect of water soluble polymer on acoustic performance of environmentally friendly acoustic foams}, journal = {FOAMS 2011 - 9th International Conference on Foam Processing and Technology}, year = {2011}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84863277617&partnerID=40&md5=9b96e7ab219adc6ca8e082eeeecedcef} } |
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Mosanenzadeh, S., Naguib, H., Park, C. and Atalla, N. | Development and characterization of environmentally friendly open-cell acoustic foams | 2011 | Annual Technical Conference - ANTEC, Conference Proceedings Vol. 3, pp. 2628-2632 |
conference | URL |
Abstract: Although polymeric open-cell foams provide adequate absorption at medium and high frequencies, they are, as the majority of absorbing materials, inefficient in the low frequency range. Through this study, open-cell polymeric foams were fabricated from Polypropylene (PP) and Polylactide (PLA) by a novel fabrication method combining particulate leaching technique and compression molding. Fabricated foams were compared with a sample of Polyurethane (PU) foam. The materials used in this study are either recyclable or biodegradable which is of great importance considering huge amount of foams used as acoustic absorbers in various industries. | |||||
BibTeX:
@conference{Mosanenzadeh20112628, author = {Mosanenzadeh, S.G. and Naguib, H.E. and Park, C.B. and Atalla, N.}, title = {Development and characterization of environmentally friendly open-cell acoustic foams}, journal = {Annual Technical Conference - ANTEC, Conference Proceedings}, year = {2011}, volume = {3}, pages = {2628-2632}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051827941&partnerID=40&md5=48b507c856b6bbca9d75554d679b4559} } |
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Mulligan, K., Ostiguy, P.-C., Masson, P., Elkoun, S. and Quaegebeur, N. | Assessment of PZT transducer bonding techniques under drop-weight impact loading in composites | 2011 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 7983 |
conference | DOI URL |
Abstract: This paper describes the robustness of a structural health monitoring system (SHM) that utilizes lead-zirconatetitanate (PZT) transducers tested on carbon fibre composite coupons under drop-weight impact loading. Four PZT transducers are attached to the surface of 10.16 cm x 15.24 cm aerospace grade carbon fibre coupons using four types of adhesives: cyanoacrylate, epoxy, methyl methacrylate, and silicon. Each PZT transducer is tuned to excite preferentially an A0 mode guided wave burst into each composite coupon prior to and following an impact. The output from a PZT transducer, the amplitude of the propagating guided waves measured using a laser vibrometer on the coupon surface and the RMS velocity is plotted. The cycle is repeated for the three remaining transducers. The electrical admittance is also measured using an impedance analyzer prior to and following impact. This paper illustrates how a robustness metric expressed in terms of admittance can be used to infer the ability of the SHM system to generate guided waves and to detect damage following impact. The robustness metric is a measure of the adhesive strength and the mechanism to provide accurate damage detection results. It is shown that transducers attached using silicon provide accurate damage detection results based on pre-attached adhesive yielding difference of <0.5% obtained from electrical admittance measurements before and after impact. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE). | |||||
BibTeX:
@conference{Mulligan2011, author = {Mulligan, K.R. and Ostiguy, P.-C. and Masson, P. and Elkoun, S. and Quaegebeur, N.}, title = {Assessment of PZT transducer bonding techniques under drop-weight impact loading in composites}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2011}, volume = {7983}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79956194460&doi=10.1117%2f12.880645&partnerID=40&md5=ed2c8b7cfa44e33e1ffe75f98050a82d}, doi = {https://doi.org/10.1117/12.880645} } |
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Ostiguy, P.-C., Masson, P., Quaegebeur, N. and Elkoun, S. | Sensitivity of the excitelet imaging algorithm on material properties for isotropic structures | 2011 | Structural Health Monitoring 2011: Condition-Based Maintenance and Intelligent Structures - Proceedings of the 8th International Workshop on Structural Health Monitoring Vol. 1, pp. 151-158 |
conference | URL |
Abstract: Imaging techniques such as EUSR or Excitelet algorithms used in guided wave damage detection rely on an accurate knowledge of group or phase velocities. The problem is that variability in material properties directly affects the guided wave dispersion curves. Traditional approaches to mechanical characterization are based on ASTM standards. However, most of these techniques require numerous specimens to test and evaluate the properties of a structure within a few percents. The main goal of this paper is to assess a new integrated characterization approach to identify the mechanical properties of an isotropic structure (Young's modulus, Poisson's ratio, density) onto which imaging is performed to detect damage. The integrated characterization approach is based on a modified version of the Excitelet algorithm, where mechanical properties, instead of geometrical features, are set as the variables to be identified. This paper thus aims at evaluating the benefit of using the same array of transducers, and similar signal processing tools, to first identify the mechanical properties of the structure using a modified version of the Excitelet algorithm and then produce an image of this structure using the standard Excitelet imaging algorithm. The experimental setup consists of an aluminum plate with a 2 mm notched hole and instrumented with a linear array of seven circular elements micro-machined from bulk piezoceramic (PZT). Excitelet imaging is performed with the linear array and the characterization uses this same array and an extra PZT transducer located in the near field of the array. In this paper, low order Lamb modes are exploited for both characterization and imaging techniques. The results obtained for the properties identified with the modified Excitelet algorithm are within 1% of properties from the material supplier. Imaging results are then presented using Excitelet with both A 0 and S 0 modes at dispersive frequencies for the localization the notch. This integrated characterization algorithm combined with the Excitelet imaging technique is shown to improve the accuracy of the localization of the damage for isotropic structures. | |||||
BibTeX:
@conference{Ostiguy2011151, author = {Ostiguy, P.-C. and Masson, P. and Quaegebeur, N. and Elkoun, S.}, title = {Sensitivity of the excitelet imaging algorithm on material properties for isotropic structures}, journal = {Structural Health Monitoring 2011: Condition-Based Maintenance and Intelligent Structures - Proceedings of the 8th International Workshop on Structural Health Monitoring}, year = {2011}, volume = {1}, pages = {151-158}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866671300&partnerID=40&md5=865891fc1561fa106da550c2f9944a7c} } |
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Panneton, R. | Training courses in acoustics in the University of Sherbrooke [Cursus de formation en acoustique de l'université de sherbrooke] [BibTeX] |
2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(3), pp. 80-81 |
article | URL |
BibTeX:
@article{Panneton201180, author = {Panneton, R.}, title = {Training courses in acoustics in the University of Sherbrooke [Cursus de formation en acoustique de l'université de sherbrooke]}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {3}, pages = {80-81}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860297872&partnerID=40&md5=ab929c76ef6fbdaf3dbc8d0360deed91} } |
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Pasco, Y., Robin, O., Bélanger, P., Berry, A. and Rajan, S. | Multi-input multi-output feedforward control of multi-harmonic gearbox vibrations using parallel adaptive notch filters in the principal component space | 2011 | Journal of Sound and Vibration Vol. 330(22), pp. 5230-5244 |
article | DOI URL |
Abstract: Rotating mechanical systems such as gearbox are known to generate vibrations at specific frequencies. The generation of asymmetric frequency sidebands around gear meshing frequencies is typical of rotating systems, and often results in amplitude-modulated disturbances. In addition, when the angular speed of such systems exhibits small time variations, a frequency-modulation of the disturbance tones is observed. Such conditions may result in difficulties for feedforward active control systems based on short, finite impulse response control filters, as was observed by previous researchers. This is mainly due to the fact that the reference signal may not provide all the gear meshing frequencies and sidebands found in the disturbance. This work investigates adaptive notch filters in the principal component space to cancel multi-harmonic gearbox vibrations. Experimental results obtained with these adaptive notch filters show good control attenuations at targeted gearbox tones, without amplification of other closely located, unreferenced tones. © 2011 Elsevier Ltd. | |||||
BibTeX:
@article{Pasco20115230, author = {Pasco, Y. and Robin, O. and Bélanger, P. and Berry, A. and Rajan, S.}, title = {Multi-input multi-output feedforward control of multi-harmonic gearbox vibrations using parallel adaptive notch filters in the principal component space}, journal = {Journal of Sound and Vibration}, year = {2011}, volume = {330}, number = {22}, pages = {5230-5244}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960974670&doi=10.1016%2fj.jsv.2011.06.008&partnerID=40&md5=84a9d7259c995679175105d4017fcb84}, doi = {https://doi.org/10.1016/j.jsv.2011.06.008} } |
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Perrier, S., Champoux, Y. and Drouet, J.-M. | Coupling a compliant structure with a Hand - Arm system using FBS | 2011 | Conference Proceedings of the Society for Experimental Mechanics Series Vol. 3, pp. 65-78 |
conference | URL |
Abstract: The vibrational behavior of a lightweight compliant structure with low damping is strongly influenced by contact with parts of the human body. In this work, a close look is taken at the influence of the hand-arm system in the context of cycling sports. Force transmitted to the hand, along with hand-arm vibration, generates discomfort and sometimes results in injury. Designing structural changes in a given road bike component with the goal of reducing discomfort requires a clear understanding, in this case, of the interaction mechanisms between the hand-arm system and the handlebar (the coupled structure). This paper describes an experimental investigation of this type of interaction between the hands and a handlebar using an FRF Based Substructuring method (FBS) to calculate the resulting dynamic behavior of the coupled structure. The equations supporting the FBS method for this particular application are presented. The compliant structure and the hand-arm system are individually characterized by mechanical mobility Frequency Response Functions (FRF) in the frequency range of 20-400 Hz. Hand mobility is obtained by using the FBS method in a reverse manner. The influence of the hands and the upper body position on hand-arm mechanical mobility is considered. The merits and limitations of using FBS are discussed. | |||||
BibTeX:
@conference{Perrier201165, author = {Perrier, S. and Champoux, Y. and Drouet, J.-M.}, title = {Coupling a compliant structure with a Hand - Arm system using FBS}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2011}, volume = {3}, pages = {65-78}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79958105224&partnerID=40&md5=b24596b46f140547a1e8bb5da10fbeda} } |
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Quaegebeur, N., Micheau, P., Masson, P. and Maslouhi, A. | Structural health monitoring strategy for detection of interlaminar delamination in composite plates | 2011 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 7984 |
conference | DOI URL |
Abstract: In this paper, a Structural Health Monitoring (SHM) strategy is proposed in order to detect interlaminar delamination in a Carbon Fiber Reinforced Polymer (CFRP) structure using guided waves. The delamination is simulated by inserting a Teflon tape between two transverse plies and the guided wave generation and measurement is ensured by piezoceramic (PZT) elements. Theoretical propagation and through-the-thickness strain distribution are first studied in order to determine the optimal configuration of the final system in terms of mode and frequency selection and piezoceramic spacing for detection of cross-sectional delamination. Finite element simulation are then used to validate the assumptions and pitch and catch measurements are performed by comparing wave propagation for different frequencies and along damaged and undamaged paths and the analysis of results is performed using Reassigned Short-Time Fourier Transform (ReSTFT). It appears that in the low frequency range (below 300 kHz), A0 mode is sensitive to the damage while in the high frequency range, S 1 and A1 modes are both very sensitive to the damage while the propagation of the S 0 mode is not much affected. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE). | |||||
BibTeX:
@conference{Quaegebeur2011, author = {Quaegebeur, N. and Micheau, P. and Masson, P. and Maslouhi, A.}, title = {Structural health monitoring strategy for detection of interlaminar delamination in composite plates}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2011}, volume = {7984}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79956188673&doi=10.1117%2f12.880532&partnerID=40&md5=73d77582a0476329a3a57ddc6f3f0ea2}, doi = {https://doi.org/10.1117/12.880532} } |
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Quaegebeur, N., Masson, P., Langlois-Demers, D. and Micheau, P. | Dispersion-based imaging for structural health monitoring using sparse and compact arrays | 2011 | Smart Materials and Structures Vol. 20(2) |
article | DOI URL |
Abstract: In this paper, a technique called 'excitelet' is presented for the imaging of damage in structures using the correlation of the signals measured at elements of piezoceramic arrays with dispersed versions of the excitation signal. This approach is presented as an extension of classical imaging techniques and takes advantage of the chirplet-based matching pursuit algorithm. The applicability for sparse and compact arrays is investigated experimentally on an aluminum plate and comparison with the existing embedded ultrasonic structural radar (EUSR) algorithm is performed for A0 and S0 modes for three frequency ranges of interest. Significant improvement of imaging quality is demonstrated with respect to imaging techniques using time-of-flight (ToF) and group velocity considerations for both sparse and compact piezoceramic array arrangements. | |||||
BibTeX:
@article{Quaegebeur2011, author = {Quaegebeur, N. and Masson, P. and Langlois-Demers, D. and Micheau, P.}, title = {Dispersion-based imaging for structural health monitoring using sparse and compact arrays}, journal = {Smart Materials and Structures}, year = {2011}, volume = {20}, number = {2}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79951619884&doi=10.1088%2f0964-1726%2f20%2f2%2f025005&partnerID=40&md5=c5f3439ab54bd4b79b5638dddd9f12e3}, doi = {https://doi.org/10.1088/0964-1726/20/2/025005} } |
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Quaegebeur, N., Masson, P., Micheau, P. and Mrad, N. | Experimental broadband estimation of guided waves group velocity with high signal to noise ratio | 2011 | Structural Health Monitoring 2011: Condition-Based Maintenance and Intelligent Structures - Proceedings of the 8th International Workshop on Structural Health Monitoring Vol. 1, pp. 1111-1118 |
conference | URL |
Abstract: Most of the damage detection and localization approaches are currently based on the measurement of a Time-of-Flight (ToF) and the knowledge of the group velocity for a mode propagating at a given frequency. In order to extract mode-related information from a time-domain signal affected by a dispersive propagation, numerous approaches have been proposed but the group velocity must be known with precision. In order to evaluate the group velocity for dispersive frequency ranges, broadband excitation patterns must be used. This works presents a cost-effective approach to estimate the group velocity from simple measurements in a given frequency range. The principle is to generate a set of properly patterned impulse signals using a piezoce-ramic (PZT) and to sense the response after propagation using either a Laser Doppler Vibrometer (LDV) or another PZT. While broadband excitation using a single impulse excitation might lead to limited wave amplitude, the originality of the present approach is to use N input signals with different central angular frequencies in order to reconstruct an impulse response. The parameters of the N input signals are optimized such that the addition of all signals has a broadband frequency content in order to increase the Signal to Noise Ratio (SNR). The experimental setup consists of an thin aluminum plate instrumented with one PZT actuator and a LDV to measure the out-of-plane displacement. The influence of the number of signals N used for the reconstruction of the impulse response and the actuator / sensor distance are investigated experimentally for frequencies below 1.5 MHz. It is shown that an increase of SNR in the impulse response measurement can be obtained for the LDV sensor and thus a better agreement between theoretical and experimental predictions of group velocity can be observed even for dispersive or multimodal propagation. | |||||
BibTeX:
@conference{Quaegebeur20111111, author = {Quaegebeur, N. and Masson, P. and Micheau, P. and Mrad, N.}, title = {Experimental broadband estimation of guided waves group velocity with high signal to noise ratio}, journal = {Structural Health Monitoring 2011: Condition-Based Maintenance and Intelligent Structures - Proceedings of the 8th International Workshop on Structural Health Monitoring}, year = {2011}, volume = {1}, pages = {1111-1118}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866723448&partnerID=40&md5=36adb430e0fa2a22579cc4126121a41c} } |
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Rakic, A., Panneton, R. and Atalla, N. | Sound package for a magnesium alloy dash panel | 2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(3), pp. 14-15 |
article | URL |
Abstract: The automobile companies such as Ford and Volkswagen decided to use magnesium alloy to replace some steel parts of the car. The magnesium alloy has several advantages over steel. It is more malleable, more ductile, lighter, and it has a higher stiffness weight ratio. However, its low mass gives a poor sound transmission loss performance compared to steel. A 3D model of a car has been designed in the statistical energy analysis (SEA) software VA ONE to calculate the average sound absorption of the car cabin. This model takes into account the sound absorption of seats, roof, floor and doors. The first concept is composed of absorbers and insulators materials. A similar structure was used for the second concept. Only a small damping material layer was added to improve the transmission loss at low frequencies. The optimization was performed on 33 different materials considering the following criteria. | |||||
BibTeX:
@article{Rakic201114, author = {Rakic, A. and Panneton, R. and Atalla, N.}, title = {Sound package for a magnesium alloy dash panel}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {3}, pages = {14-15}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859492699&partnerID=40&md5=a753b939a9c6aae008b294cdf6623357} } |
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Regnard, J.-P., Panneton, R., Elkoun, S. and Oddo, R. | Transmission loss of a sound insulating panel made from charged recyclable thermoplastic | 2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(3), pp. 20-21 |
article | URL |
Abstract: This article aims at investigating the sound insulation property of composites made of recyclable thermoplastic charged with heavy particles. Polyethylene (PE) is the most used thermoplastic polymer worldwide. Behind this generic name lies several types of PE, where linear low density polyethylene (LLDPE) is the most common one. Metal particles are often used to improve the electrical properties of materials. However Young modulus increases too. Subsequently, and in order to reduce composites rigidity, samples microstructure was modified by subjected all composites to a special procedure. Then, Young modulus was again reevaluated. Buoyancy method was used to assess the composites density. In this work, it was shown that the sound insulation properties of a material made of recyclable thermoplastic can be assessed by the rigidity to density ratio, and, enhanced by reducing this ratio. | |||||
BibTeX:
@article{Regnard201120, author = {Regnard, J.-P. and Panneton, R. and Elkoun, S. and Oddo, R.}, title = {Transmission loss of a sound insulating panel made from charged recyclable thermoplastic}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {3}, pages = {20-21}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859492086&partnerID=40&md5=d3fae63082fc5786aa256db72addf090} } |
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Ren, Z., Atalla, N. and Ghinet, S. | Optimization based identification of the dynamic properties of linearly viscoelastic materials using vibrating beam technique | 2011 | Journal of Vibration and Acoustics, Transactions of the ASME Vol. 133(4) |
article | DOI URL |
Abstract: Sandwich structures with viscoelastic core and metal face sheets are increasingly used in automotive industry to significantly reduce the amplitude of vibration and noise radiation. Several experimental methods such as dynamic mechanical analysis (DMA) and vibrating beam technique (VBT) are used to characterize the dynamic properties of viscoelastic materials as a function of frequency and temperature. This paper investigates the use of a free-free beam setup, as an alternative solution to the classical clamped-free VBT, for a better control of the effect of boundary conditions on the laminated steel specimen. The new setup is developed in combination with a frequency response function based optimization method, to automatically derive the dynamic properties of viscoelastic core materials and generate their master curves. A solver based on the normal mode superposition method, considering the added mass effect of the impedance head, is used in the cost function of the optimization approach. The sandwich model is based on the Ross-Kerwin-Ungar equation, and the four-parameter fractional derivative model is used in conjunction with the Williams-Landel-Ferry equation to describe the frequency and temperature dependent behavior of the viscoelastic material. The master curves are a direct result of the optimization process. Several applications are described to assess the performance of the present method. In particular, a systematic comparison with both the classical VBT and DMA (when available) is presented. © 2011 American Society of Mechanical Engineers. | |||||
BibTeX:
@article{Ren2011, author = {Ren, Z. and Atalla, N. and Ghinet, S.}, title = {Optimization based identification of the dynamic properties of linearly viscoelastic materials using vibrating beam technique}, journal = {Journal of Vibration and Acoustics, Transactions of the ASME}, year = {2011}, volume = {133}, number = {4}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955634187&doi=10.1115%2f1.4003594&partnerID=40&md5=5e488abdae97ae7db384c73012107cbf}, doi = {https://doi.org/10.1115/1.4003594} } |
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Robin, O., Dia, R., Berry, A. and Moreau, S. | Utilisation de techniques de reproduction de champs sonores pour la synthèse de champs spatialement corrélés [BibTeX] |
2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(3), pp. 26-27 |
article | URL |
BibTeX:
@article{Robin201126, author = {Robin, O. and Dia, R. and Berry, A. and Moreau, S.}, title = {Utilisation de techniques de reproduction de champs sonores pour la synthèse de champs spatialement corrélés}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {3}, pages = {26-27}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859793645&partnerID=40&md5=4fcdbd3808beb263bb85927d80845d1c} } |
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Salissou, Y., Panneton, R. and Doutres, O. | Three-microphone two-cavity method for measuring sound transmission loss in a modified impedance tube | 2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(3), pp. 16-17 |
article | URL |
Abstract: The normal incidence sound transmission loss (nSTL) is an important indicator to assess the sound insulation property of acoustic materials. The apparatus consists of a finite length rigid walled impedance tube with circularly shaped and uniform inner cross-section. The tube features a loudspeaker at one end and a movable piston at the other end. The loudspeaker is used to generate a plane wave field in the impedance tube. There are two microphones flush mounted upstream the test sample and one microphone flush mounted on the rigid end. Next, a 20-mm thick step discontinuity seeing as a non-symmetrical sample is tested and compared to the standard 4M2L method and 3M-TMTC method. One can note that similar results are obtained between the 3M2L and 4M2L methods, however 4M2L is noisier compared to 3M2L. | |||||
BibTeX:
@article{Salissou201116, author = {Salissou, Y. and Panneton, R. and Doutres, O.}, title = {Three-microphone two-cavity method for measuring sound transmission loss in a modified impedance tube}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {3}, pages = {16-17}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859502010&partnerID=40&md5=c7f5a6d147b660807cb2816cb7e28adc} } |
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Sgard, F., Castel, F. and Atalla, N. | Use of a hybrid adaptive finite element/modal approach to assess the sound absorption of porous materials with meso-heterogeneities | 2011 | Applied Acoustics Vol. 72(4), pp. 157-168 |
article | DOI URL |
Abstract: The paper discusses the sound absorptive performance of a porous material with meso-perforations inserted in a rectangular waveguide using a numerical hybrid adaptive finite element-modal method. Two specific applications are investigated: (i) the improvement of porous materials noise reduction coefficient using meso-perforations (ii) the effects of lateral air gaps on the normal incidence sound absorption of mono-layer and two-layer porous materials. For the first application, a numerical design of experiments is used to optimize the sound performance of a porous material with meso-perforations with a reduced number of numerical simulation. An example in which the optimization process is carried out on the thickness and size of the perforation is presented to illustrate the relevance of the approach. For the second application, a set of twenty fibrous materials spanning a large flow resistivity range is used. Practical charts are proposed to evaluate the influence of air gaps on the average sound absorption performance of porous materials. This is helpful to both the experimenter regarding characterization of porous material based on Standing Wave Tube measurements and for the engineer to quantifying the impact of air gaps and for designing efficient absorbers. © 2010 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Sgard2011157, author = {Sgard, F. and Castel, F. and Atalla, N.}, title = {Use of a hybrid adaptive finite element/modal approach to assess the sound absorption of porous materials with meso-heterogeneities}, journal = {Applied Acoustics}, year = {2011}, volume = {72}, number = {4}, pages = {157-168}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650845695&doi=10.1016%2fj.apacoust.2010.10.011&partnerID=40&md5=8c6594a3d515de6b3c52163286d496b9}, doi = {https://doi.org/10.1016/j.apacoust.2010.10.011} } |
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Vadavalli, V., Moreau, S. and Atalla, N. | Statistical properties of pressure loadings and vibroacoustic response of a simplified side glass induced by the flow over generic flow-deflector and side-mirror | 2011 | 17th AIAA/CEAS Aeroacoustics Conference 2011 (32nd AIAA Aeroacoustics Conference) | conference | URL |
Abstract: The statistical description of the wall pressure fluctuations in a non-equilibrium turbulent boundary layer (TBL) on a plate with two typical bluff bodies a side mirror and a flat fence is presented. To achieve statistically converged turbulent flow, a long time history computational fluid dynamics (CFD) simulation was conducted with the Lattice-Boltzmann solver PowerFLOW. It provided the unsteady wall pressure on the plate. Mean flow, wall pressure spectra and two point correlations of the wall-pressure results are validated for both cases with experiments run in the anechoic wind tunnel at Purdue University. From a spatial temporal analysis of the turbulent flow the convection and acoustic zones are captured correctly, which are major sources of excitation and transmission respectively. Using the CFD wall-pressure coherence on the plate, zonal Corcos' model parameters like convection velocity and decay coefficients have been determined by least-square curve fitting. The identified empirical model parameters are validated with experimental values and later used to predict the vibroacoustic indicators for the plate. Vibroacoustic indicators for a side mirror case are calculated using both CFD-derived parameters and finite element method. These results are validated with experiments on a plate-cavity system. © 2011 by the author(s). | |||||
BibTeX:
@conference{Vadavalli2011, author = {Vadavalli, V.P.K. and Moreau, S. and Atalla, N.}, title = {Statistical properties of pressure loadings and vibroacoustic response of a simplified side glass induced by the flow over generic flow-deflector and side-mirror}, journal = {17th AIAA/CEAS Aeroacoustics Conference 2011 (32nd AIAA Aeroacoustics Conference)}, year = {2011}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883118785&partnerID=40&md5=1257b00970a466af1afbe9fc2735e7a9} } |
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Verdière, K., Panneton, R., Elkoun, S., Lavoie, J. and Oddo, R. | Switchgrass-based noise absorbing material: Characterization and modeling | 2011 | Canadian Acoustics - Acoustique Canadienne Vol. 39(3), pp. 24-25 |
article | URL |
Abstract: Switchgrass is a tall grass plant largely present in North America and especially in Canada. It grows from rhizomes and is characterized by stems that can reach, like bamboo or sugarcane, up to 2 meters high. Moreover, its roots can be as deep as 2 meters. It is important to mention that during the measurement, samples were not compressed. The only pressure to which they were subjected were their own weight. This model takes into account geometrical parameters of spheres, the porosity and the space between two adjacent layers of spheres. This approach can be applied as far as one can approximate the shape of switchgrass stems by a sphere. Two models were used to simulate the sound absorption coefficient and compared to experimental data. The Johnson Champoux Alard model was shown to be the most reliable model which allows the assumption that it can be used to find the optimal thickness for the design of switchgrass-based sound absorbing panels. | |||||
BibTeX:
@article{Verdière201124, author = {Verdière, K. and Panneton, R. and Elkoun, S. and Lavoie, J.M. and Oddo, R.}, title = {Switchgrass-based noise absorbing material: Characterization and modeling}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2011}, volume = {39}, number = {3}, pages = {24-25}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859501354&partnerID=40&md5=527ff729b47c348f64a40f8190468364} } |
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Verron, C., Gauthier, P.-A., Langlois, J. and Guastavino, C. | Binaural analysis/synthesis of interior aircraft sounds | 2011 | IEEE Workshop on Applications of Signal Processing to Audio and Acoustics, pp. 177-180 | conference | DOI URL |
Abstract: A binaural sinusoids+noise synthesis model is proposed for reproducing interior aircraft sounds. First, a method for spectral and spatial characterization of binaural interior aircraft sounds is presented. This characterization relies on a stationarity hypothesis and involves four estimators: left and right power spectra, interaural coherence and interaural phase difference. Then we present two extensions of the classical sinusoids+noise model for the analysis and synthesis of stationary binaural sounds. First, we propose a binaural estimator using relevant information in both left and right channels for peak detection. Second, the residual modeling is extended to integrate two interaural spatial cues, namely coherence and phase difference. The resulting binaural sinusoids+noise model is evaluated on a recorded aircraft sound. © 2011 IEEE. | |||||
BibTeX:
@conference{Verron2011177, author = {Verron, C. and Gauthier, P.-A. and Langlois, J. and Guastavino, C.}, title = {Binaural analysis/synthesis of interior aircraft sounds}, journal = {IEEE Workshop on Applications of Signal Processing to Audio and Acoustics}, year = {2011}, pages = {177-180}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-83455262400&doi=10.1109%2fASPAA.2011.6082313&partnerID=40&md5=e7380c6c4d6940dc676685ec18c5ad71}, doi = {https://doi.org/10.1109/ASPAA.2011.6082313} } |
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Abderrazak, M. and Atalla, N. | A semi-analytical method to predict the vibroacoustics response of composite and isotropic stiffened panels | 2010 | 24th National Conference on Noise Control Engineering 2010, Noise-Con 10, Held Jointly with the 159th Meeting of the Acoustical Society of America Vol. 3, pp. 1363-1373 |
conference | URL |
Abstract: The vibroacoustics behavior of aircraft-type stiffened panels is classically analyzed using deterministic methods such as the finite element and boundary element method at low frequencies or energy based methods at higher frequencies. In the present work, a general semi-analytical method based on modal expansion technique is developed to predict the vibration and acoustics radiation of both metallic and composite flat stiffened panels. Both unidirectional and bidirectional stiffened panel with eccentric stiffeners and various shapes are analyzed using the same matrix formulation. The presented model is also able to predict the response of both regular and irregular stiffened panels. The contributions of the force and moment modal coupling at each beam location are accounted for together with the effect of interaction between ribs in the case of orthogonal stiffened plate. The response to various types of excitations (point force, Diffuse Acoustic Field and Turbulent Boundary Layer) are presented in terms of their joint acceptance. The model is numerically validated by comparison with the FEM/BEM and hybrid FEM/SEA methods for various configurations and excitations. Excellent agreement is found. | |||||
BibTeX:
@conference{Abderrazak20101363, author = {Abderrazak, M. and Atalla, N.}, title = {A semi-analytical method to predict the vibroacoustics response of composite and isotropic stiffened panels}, journal = {24th National Conference on Noise Control Engineering 2010, Noise-Con 10, Held Jointly with the 159th Meeting of the Acoustical Society of America}, year = {2010}, volume = {3}, pages = {1363-1373}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869412727&partnerID=40&md5=44f402d855ab2f4424cdec434a0b6ee3} } |
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Amichi, K., Atalla, N. and Sgard, F. | Sound radiation of orthotropic curved sandwich structures using a mixed boundary element/finite element approach | 2010 | 20th International Congress on Acoustics 2010, ICA 2010 - Incorporating Proceedings of the 2010 Annual Conference of the Australian Acoustical Society Vol. 2, pp. 1082-1088 |
conference | URL |
Abstract: Sandwich structures such as composite skins-Honeycomb core (NIDA) and Metal skins-Polymer core (MPM) panels are increasingly used in the aeronautics and automobile industries, respectively. It has been shown that this class of structures enables manufacturers to cut weight and cost while providing vibration and harshness performance. These materials induce however increased sound radiation which unfortunately leads, in some instances, to higher interior noise levels. In consequence, there is a need for accurate and reliable low cost numerical tools to efficiently estimate and optimize the vibroacoustic behaviours of such structures. This paper deals with the prediction of the vibroacoustic behaviour of curved orthotropic sandwich panels. A sandwich finite element is first presented and its ability to predict accurately and efficiently the structural response for such structures demonstrated by comparison with classical 3D solid modeling. Next, the element is used within a mixed boundary element/finite element approach (BEM/FEM) to illustrate the effect of curvature and orthotropy on the airborne sound transmission performance of these panels. Examples are presented which consist of both sandwich honeycombs and MPM panels. Copyright© (2010) by the International Congress on Acoustics. | |||||
BibTeX:
@conference{Amichi20101082, author = {Amichi, K. and Atalla, N. and Sgard, F.}, title = {Sound radiation of orthotropic curved sandwich structures using a mixed boundary element/finite element approach}, journal = {20th International Congress on Acoustics 2010, ICA 2010 - Incorporating Proceedings of the 2010 Annual Conference of the Australian Acoustical Society}, year = {2010}, volume = {2}, pages = {1082-1088}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869110743&partnerID=40&md5=0ed8936b9ebbe2aacd04ee0b7448bed3} } |
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Amichi, K., Atalla, N. and Ruokolainen, R. | A new 3D finite element sandwich plate for predicting the vibroacoustic response of laminated steel panels | 2010 | Finite Elements in Analysis and Design Vol. 46(12), pp. 1131-1145 |
article | DOI URL |
Abstract: A new sandwich finite element has been previously applied successfully to the vibration analysis of damped metalpolymermetal beams [1]. In this paper, this element is extended to the vibration of unsymmetrical sandwich plates with a viscoelastic core. The rotational influence of the transversal shearing in the core on the skins behaviour, ensures a displacement consistency over the interfaces between the viscoelastic core and the elastic skins resulting in accurate representations of the physics. To enable the analysis of plates with arbitrary orientation in three-dimensional space, a formulation with nine degrees of freedom per node is employed. Moreover, the element is shown to interface easily with classical plate's elements. Comparisons with both experimental tests and classical solid FE modeling are shown to prove the accuracy and computational efficiency of the presented element for the modeling of the vibro-acoustic response of the studied metalpolymermetal panels. © 2010 Elsevier B.V. All rights reserved. | |||||
BibTeX:
@article{Amichi20101131, author = {Amichi, K. and Atalla, N. and Ruokolainen, R.}, title = {A new 3D finite element sandwich plate for predicting the vibroacoustic response of laminated steel panels}, journal = {Finite Elements in Analysis and Design}, year = {2010}, volume = {46}, number = {12}, pages = {1131-1145}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956920942&doi=10.1016%2fj.finel.2010.07.002&partnerID=40&md5=4f830bc3381cbf441193b0058b54b3f1}, doi = {https://doi.org/10.1016/j.finel.2010.07.002} } |
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Atalla, Y., Fu, J., Atalla, N. and Naguib, H. | Study of the effects of processing parameters on the sound absorption of open-cell microcellular polymeric foams | 2010 | Noise Control Engineering Journal Vol. 58(1), pp. 18-26 |
article | DOI URL |
Abstract: Various researchers have investigated microcellular polymeric foams extensively over the last twenty years or so; however, little work has been conducted on the acoustic performance of these foams when their microstructural components are modified by controlling the manufacturing process parameters. The studies discussed in this paper represent an initial stage in the development of open cell foams that exhibit optimized acoustic performance as a result of controlling processing parameters. This study was focused to understand and control certain parameters that dictate the material's microstructure, such as cell size, and link them to the main macroscopic parameters, such as the airflow resistivity and porosity, which govern the overall sound absorption of an open cell material. In this paper, we investigate a new processing technology to manufacture open-cell sound absorbing PMMA (Poly Methyl Methacrylate) materials using a gas foaming/particulate leaching method. An acoustic parametric study is conducted by altering the main processing parameters such as foaming temperature, particle size, and percentage of foaming agent, which affect the cell morphologies and thus control the macroscopic properties. As such, we explore the effects of the adjusted processing parameters on the acoustic performance of the manufactured PMMA samples. The correlations between the resulting cell morphologies and the sound absorption properties indicate that understanding and controlling the porous material's inner structure is crucial for developing any type of open-cell porous material with optimal acoustical efficiency. © 2010 Institute of Noise Control Engineering. | |||||
BibTeX:
@article{Atalla201018, author = {Atalla, Y. and Fu, J. and Atalla, N. and Naguib, H.E.}, title = {Study of the effects of processing parameters on the sound absorption of open-cell microcellular polymeric foams}, journal = {Noise Control Engineering Journal}, year = {2010}, volume = {58}, number = {1}, pages = {18-26}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77949415986&doi=10.3397%2f1.3264660&partnerID=40&md5=fe7c590b683b511e38d649ca5dd5d5ff}, doi = {https://doi.org/10.3397/1.3264660} } |
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Bergeron, F., Astruc, C., Berry, A. and Masson, P. | Sound quality assessment of internal automotive road noise using sensory science | 2010 | Acta Acustica united with Acustica Vol. 96(3), pp. 580-588 |
article | DOI URL |
Abstract: This paper presents a technique to describe the perception of internal automotive road noise. As the acoustic sources on a car reach lower sound levels, special attention is granted to acoustical comfort. While the knowledge of mechanisms behind road noise is growing, its perception by the driver remains relatively unexplored. In this study, a sensory science technique - the classical sensory profile - is applied to obtain a description of the internal road noise by quantitative perceptual criteria. Seven consumer cars (from Renault, Fiat, Peugeot, and Toyota) were driven under four well-defined conditions varying in speed and road surface. Twenty-one typical road noise recordings were presented to a panel of five experts in acoustics. Twelve listening sessions of three hours, individually and in group, led to a list of 15 relevant perceptual descriptors, such as "rough aspect". The performance of the listeners was tested statistically: their repeatability, their ability to discriminate the sounds and the inter-subject agreement. Sufficient agreement was observed across the listeners for 10 of the 15 descriptors, which would constitute the perceptual basis for internal automotive road noise. Through multiple linear regression, strong correlations were found between the associated perceptual dimensions and psychoacoustic properties of the sound samples. The findings from this study are summarized in a sensory grid to assist the test drivers in the evaluation of road noise sound character, and a predictive tool for sound quality evaluation based on correlations between perceptual dimensions and calculated sound metrics. © S. Hirzel Verlag. | |||||
BibTeX:
@article{Bergeron2010580, author = {Bergeron, F. and Astruc, C. and Berry, A. and Masson, P.}, title = {Sound quality assessment of internal automotive road noise using sensory science}, journal = {Acta Acustica united with Acustica}, year = {2010}, volume = {96}, number = {3}, pages = {580-588}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77952990138&doi=10.3813%2fAAA.918308&partnerID=40&md5=5a8087aa05333f5c7ec4571ef8428eb5}, doi = {https://doi.org/10.3813/AAA.918308} } |
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Bossé, D., Beaulieu, A., Avoine, O., Micheau, P., Praud, J.-P. and Walti, H. | Neonatal total liquid ventilation: Is low-frequency forced oscillation technique suitable for respiratory mechanics assessment? | 2010 | Journal of Applied Physiology Vol. 109(2), pp. 501-510 |
article | DOI URL |
Abstract: This study aimed to implement low-frequency forced oscillation technique (LFFOT) in neonatal total liquid ventilation (TLV) and to provide the first insight into respiratory impedance under this new modality of ventilation. Thirteen newborn lambs, weighing 2.5 ± 0.4 kg (mean ± SD), were premedicated, intubated, anesthetized, and then placed under TLV using a specially design liquid ventilator and a perfluorocarbon. The respiratory mechanics measurements protocol was started immediately after TLV initiation. Three blocks of measurements were first performed: one during initial respiratory system adaptation to TLV, followed by two other series during steady-state conditions. Lambs were then divided into two groups before undergoing another three blocks of measurements: the first group received a 10-min intravenous infusion of salbutamol (1.5 µg·kg-1 ·min-1) after continuous infusion of methacholine (9 µg·kg-1 ·min-1), while the second group of lambs was chest strapped. Respiratory impedance was measured using serial single-frequency tests at frequencies ranging between 0.05 and 2 Hz and then fitted with a constant-phase model. Harmonic test signals of 0.2 Hz were also launched every 10 min throughout the measurement protocol. Airway resistance and inertance were starkly increased in TLV compared with gas ventilation, with a resonant frequency =1.2 Hz. Resistance of 0.2 Hz and reactance were sensitive to bronchoconstriction and dilation, as well as during compliance reduction. We report successful implementation of LFFOT to neonatal TLV and present the first insight into respiratory impedance under this new modality of ventilation. We show that LFFOT is an effective tool to track respiratory mechanics under TLV. © 2010 the American Physiological Society. | |||||
BibTeX:
@article{Bossé2010501, author = {Bossé, D. and Beaulieu, A. and Avoine, O. and Micheau, P. and Praud, J.-P. and Walti, H.}, title = {Neonatal total liquid ventilation: Is low-frequency forced oscillation technique suitable for respiratory mechanics assessment?}, journal = {Journal of Applied Physiology}, year = {2010}, volume = {109}, number = {2}, pages = {501-510}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955607951&doi=10.1152%2fjapplphysiol.01042.2009&partnerID=40&md5=4989428cc28055086819819b2bf40bca}, doi = {https://doi.org/10.1152/japplphysiol.01042.2009} } |
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Bossé, D., Walti, H., Robert, R., Lebon, J., Lesur, O., Praud, J.-P. and Micheau, P. | Experimental validation of cardiac index measurement using transpulmonary thermodilution technique in neonatal total liquid ventilation | 2010 | ASAIO Journal Vol. 56(6), pp. 557-562 |
article | DOI URL |
Abstract: This study aimed to assess the precision and the interchangeability of cardiac index measurement by transpulmonary thermodilution (TPTD) and pulmonary thermodilution (PTD) devices on a neonatal animal model of acute respiratory distress syndrome under total liquid ventilation (TLV) and conventional mechanical ventilation (CMV). After acute respiratory distress induction by tracheal instillation of hydrochloric acid, transpulmonary (CITPTD) and pulmonary (CIPTD) cardiac index were simultaneously measured every 30 minutes for a 240-minute experiment. Reproducibility of both thermodilution techniques was very good to excellent in both groups of ventilation with intrainstrument intraclass correlation coefficient >0.60. Disagreement was found between TPTD and PTD in TLV and CMV. Bland-Altman analysis revealed mean biases of 0.98 L/min/m (22.8%) with limits of agreement of-1.33 to 3.25 L/min/m in CMV and 1.28 L/min/m (17.3%) with limits of agreement of-1.17 to 3.72 L/min/m in TLV. Bias between TPTD and PTD was not statistically different in TLV than in CMV (p = 0.11). Transpulmonary thermodilution and PTD remained precise but not interchangeable techniques under TLV as well as CMV. Because TLV does not bring additional bias between both thermodilution techniques, we advocate the use of the less-invasive TPTD under TLV as currently recommended in CMV. © 2010 American Society of Artificial Internal Organs. | |||||
BibTeX:
@article{Bossé2010557, author = {Bossé, D. and Walti, H. and Robert, R. and Lebon, J. and Lesur, O. and Praud, J.-P. and Micheau, P.}, title = {Experimental validation of cardiac index measurement using transpulmonary thermodilution technique in neonatal total liquid ventilation}, journal = {ASAIO Journal}, year = {2010}, volume = {56}, number = {6}, pages = {557-562}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78349303028&doi=10.1097%2fMAT.0b013e3181f1cd72&partnerID=40&md5=10ea443ba1e0f86155d7192c79bfd55a}, doi = {https://doi.org/10.1097/MAT.0b013e3181f1cd72} } |
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Chevillotte, F., Perrot, C. and Panneton, R. | Microstructure based model for sound absorption predictions of perforated closed-cell metallic foams. | 2010 | The Journal of the Acoustical Society of America Vol. 128(4), pp. 1766-1776 |
article | URL |
Abstract: Closed-cell metallic foams are known for their rigidity, lightness, thermal conductivity as well as their low production cost compared to open-cell metallic foams. However, they are also poor sound absorbers. Similarly to a rigid solid, a method to enhance their sound absorption is to perforate them. This method has shown good preliminary results but has not yet been analyzed from a microstructure point of view. The objective of this work is to better understand how perforations interact with closed-cell foam microstructure and how it modifies the sound absorption of the foam. A simple two-dimensional microstructural model of the perforated closed-cell metallic foam is presented and numerically solved. A rough three-dimensional conversion of the two-dimensional results is proposed. The results obtained with the calculation method show that the perforated closed-cell foam behaves similarly to a perforated solid; however, its sound absorption is modulated by the foam microstructure, and most particularly by the diameters of both perforation and pore. A comparison with measurements demonstrates that the proposed calculation method yields realistic trends. Some design guides are also proposed. | |||||
BibTeX:
@article{Chevillotte20101766, author = {Chevillotte, F. and Perrot, C. and Panneton, R.}, title = {Microstructure based model for sound absorption predictions of perforated closed-cell metallic foams.}, journal = {The Journal of the Acoustical Society of America}, year = {2010}, volume = {128}, number = {4}, pages = {1766-1776}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952198092&partnerID=40&md5=065a705f0efb989a7a9f551ed1603ff3} } |
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Chevillotte, F., Panneton, R. and Perrot, C. | Microstructure based model for sound absorption predictions of perforated closedcell metallic foams | 2010 | 17th International Congress on Sound and Vibration 2010, ICSV 2010 Vol. 4, pp. 2909-2916 |
conference | URL |
Abstract: Closed-cell metallic foams are known for their rigidity, their lightness, their thermal conductivity as well as their low production cost compared to open-cell metallic foams. Yet, they are also poor sound absorbers. A method to enhance their sound absorption is to perforate them. This method has shown good preliminary results but has not yet been analyzed from a microstructural point of view. The objective of this work is to better understand how perforations modify the sound absorption of closed-cell metallic foams. First, a simple twodimensional (2D) microstructural model of the perforated closed-cell metallic foam is proposed and solved through numerical homogenization. A rough three-dimensional (3D) correction of the 2D results is then given from the standpoint of straightforward examination of the analytical slits/cylinders macroscopic parameters. The results show that the diameter of both the perforation and the pore appear as the main controlling parameters of the sound absorption behavior. An experimental comparison demonstrates that the 2D proposed microstructural numerical model combined with a 3D analytical correction factor yields realistic trends for optimization purposes. | |||||
BibTeX:
@conference{Chevillotte20102909, author = {Chevillotte, F. and Panneton, R. and Perrot, C.}, title = {Microstructure based model for sound absorption predictions of perforated closedcell metallic foams}, journal = {17th International Congress on Sound and Vibration 2010, ICSV 2010}, year = {2010}, volume = {4}, pages = {2909-2916}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871404139&partnerID=40&md5=a548a1bc06e1ae085bdb5f378f56b747} } |
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Chu, R., Park, C. and Atalla, N. | Acoustics of thermoplastics elastomer foam | 2010 | Society of Plastics Engineers - 9th Thermoplastic Elastomers, TPE TOPCON 2010, pp. 239-250 | conference | URL |
Abstract: Cellular foams with open-celled morphologies possess the capability of absorbing sound energy. In this paper, the acoustic absorption characteristics of open-celled foams fabricated from four polyolefin-based materials were investigated. These four matrix materials possess a material hardness of 70 and above in the Shore OOO-S scale. Through the use of different matrix materials, the effect of the matrix hardness on acoustic absorption can be elucidated. Since the rheological properties of each matrix are different, varying the matrix material will have coupled effects onto both the softness of the foam as well as the foamability and cell morphology of the foam. To decouple these effects, open-celled foam specimens of the four matrix materials were synthesized using the technique of particulate leaching. These foam structures were characterized in terms of their foam hardness and acoustics absorption characteristics. Results from this study demonstrated that foams made of softer matrix materials possess better acoustic absorption ability. | |||||
BibTeX:
@conference{Chu2010239, author = {Chu, R.K.M. and Park, C.B. and Atalla, N.}, title = {Acoustics of thermoplastics elastomer foam}, journal = {Society of Plastics Engineers - 9th Thermoplastic Elastomers, TPE TOPCON 2010}, year = {2010}, pages = {239-250}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649372096&partnerID=40&md5=f970ef7aa2d73cfa64b9d3d068600654} } |
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Doutres, O., Salissou, Y., Atalla, N. and Panneton, R. | Evaluation of the acoustic and non-acoustic properties of sound absorbing materials using a three-microphone impedance tube | 2010 | Applied Acoustics Vol. 71(6), pp. 506-509 |
article | DOI URL |
Abstract: This paper presents a straightforward application of an indirect method based on a three-microphone impedance tube setup to determine the non-acoustic properties of a sound absorbing porous material. First, a three-microphone impedance tube technique is used to measure some acoustic properties of the material (i.e., sound absorption coefficient, sound transmission loss, effective density and effective bulk modulus) regarded here as an equivalent fluid. Second, an indirect characterization allows one to extract its non-acoustic properties (i.e., static airflow resistivity, tortuosity, viscous and thermal characteristic lengths) from the measured effective properties and the material open porosity. The procedure is applied to four different sound absorbing materials and results of the characterization are compared with existing direct and inverse methods. Predictions of the acoustic behavior using an equivalent fluid model and the found non-acoustic properties are in good agreement with impedance tube measurements. © 2010 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Doutres2010506, author = {Doutres, O. and Salissou, Y. and Atalla, N. and Panneton, R.}, title = {Evaluation of the acoustic and non-acoustic properties of sound absorbing materials using a three-microphone impedance tube}, journal = {Applied Acoustics}, year = {2010}, volume = {71}, number = {6}, pages = {506-509}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77249164126&doi=10.1016%2fj.apacoust.2010.01.007&partnerID=40&md5=e1de4f51c8469ae37ea6b8ae66ff7d8d}, doi = {https://doi.org/10.1016/j.apacoust.2010.01.007} } |
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Doutres, O. and Atalla, N. | Acoustic contributions of a sound absorbing blanket placed in a double panel structure: Absorption versus transmission | 2010 | Journal of the Acoustical Society of America Vol. 128(2), pp. 664-671 |
article | DOI URL |
Abstract: The objective of this paper is to propose a simple tool to estimate the absorption vs. transmission loss contributions of a multilayered blanket unbounded in a double panel structure and thus guide its optimization. The normal incidence airborne sound transmission loss of the double panel structure, without structure-borne connections, is written in terms of three main contributions; (i) sound transmission loss of the panels, (ii) sound transmission loss of the blanket and (iii) sound absorption due to multiple reflections inside the cavity. The method is applied to four different blankets frequently used in automotive and aeronautic applications: a non-symmetric multilayer made of a screen in sandwich between two porous layers and three symmetric porous layers having different pore geometries. It is shown that the absorption behavior of the blanket controls the acoustic behavior of the treatment at low and medium frequencies and its transmission loss at high frequencies. Acoustic treatment having poor sound absorption behavior can affect the performance of the double panel structure. © 2010 Acoustical Society of America. | |||||
BibTeX:
@article{Doutres2010664, author = {Doutres, O. and Atalla, N.}, title = {Acoustic contributions of a sound absorbing blanket placed in a double panel structure: Absorption versus transmission}, journal = {Journal of the Acoustical Society of America}, year = {2010}, volume = {128}, number = {2}, pages = {664-671}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955779882&doi=10.1121%2f1.3458845&partnerID=40&md5=00bfb71709d0a9bdfaa754788a06c7a7}, doi = {https://doi.org/10.1121/1.3458845} } |
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Drouet, J.-M. and Champoux, Y. | A novel dynamometric hubset design to measure wheel loads in road cycling | 2010 | Procedia Engineering Vol. 2(2), pp. 2925-2930 |
conference | DOI URL |
Abstract: The aim of this research is to develop a dynamometric road bicycle hubset to enable wheel load measurements while correctly taking into account the end support conditions of the axles. A new hubset design is proposed, providing a way to measure vertical and horizontal forces at each end of the hub axles and to obtain all the ground contact loads acting on the bicycle wheels while pedalling or coasting. This paper presents results for ground contact loads when climbing out of the saddle and for road impact at the wheels. | |||||
BibTeX:
@conference{Drouet20102925, author = {Drouet, J.-M. and Champoux, Y.}, title = {A novel dynamometric hubset design to measure wheel loads in road cycling}, journal = {Procedia Engineering}, year = {2010}, volume = {2}, number = {2}, pages = {2925-2930}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78149342426&doi=10.1016%2fj.proeng.2010.04.089&partnerID=40&md5=f3ad442b82dfc6ecea88b2438f5caa7f}, doi = {https://doi.org/10.1016/j.proeng.2010.04.089} } |
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Duvareille, C., Beaudry, B., St-Hilaire, M., Boheimier, M., Brunel, C., Micheau, P. and Praud, J.-P. | Validation of a new automatic smoking machine to study the effects of cigarette smoke in newborn lambs | 2010 | Laboratory Animals Vol. 44(4), pp. 290-297 |
article | DOI URL |
Abstract: The aim of this study was to describe the characteristics and validate the use of a new, custom-built automatic smoking machine (ASM), primarily designed to study the effects of an environmental tobacco smoke surrogate (ETS surrogate) exposure in animals of various sizes, including large animals. The equipment includes a programmable ASM coupled to a vented whole body chamber, where animals can be exposed to both mainstream and sidestream smoke. The user-friendly interface allows for full programming of puff volume (1-60 mL), time interval between two puffs (1-60 s) and between two cigarettes (1-60 min). Eight newborn lambs were exposed to either 10 (4 lambs, C10 group) or 20 (4 lambs, C20 group) cigarettes, 8 h per day for 15 days. Four additional control, lambs were exposed to air (C0 group). Weight gain was identical in all three groups of lambs. Urinary cotinine/creatinine ratio increased with the number of cigarettes smoked (C0: 11±7 ng/mg; C10: 961±539 ng/mg; C20: 1821±312 ng/mg), with levels in the C10 and C20 groups in keeping with values published in infants exposed to ETS. Overall, results show that our new ASM is especially well suited for ETS surrogate exposure in non-restrained, non-anaesthetized large animals such as sheep. | |||||
BibTeX:
@article{Duvareille2010290, author = {Duvareille, C. and Beaudry, B. and St-Hilaire, M. and Boheimier, M. and Brunel, C. and Micheau, P. and Praud, J.-P.}, title = {Validation of a new automatic smoking machine to study the effects of cigarette smoke in newborn lambs}, journal = {Laboratory Animals}, year = {2010}, volume = {44}, number = {4}, pages = {290-297}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77958061712&doi=10.1258%2fla.2010.009124&partnerID=40&md5=7433f2fcd42d5f43a5c37f6dc2ff4c9c}, doi = {https://doi.org/10.1258/la.2010.009124} } |
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Gauthier, J.-P. and Micheau, P. | A model based on experimental data for high speed steel belt CVT | 2010 | Mechanism and Machine Theory Vol. 45(11), pp. 1733-1744 |
article | DOI URL |
Abstract: Knowing that modern small engines can run at speeds exceeding 7000 RPM, a CVT model for high rotating speed applications is proposed. The experimental results show that significant differences lie between the 0-2000 RPM models and the experimental 0-7000 RPM data, even in steady state. Dependencies on rotating speed arise even if the actuation forces are compensated for centrifugal effect. The proposed model is validated for rotating speeds from 0 to 7000 RPM at the input of the variator. © 2010 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Gauthier20101733, author = {Gauthier, J.-P. and Micheau, P.}, title = {A model based on experimental data for high speed steel belt CVT}, journal = {Mechanism and Machine Theory}, year = {2010}, volume = {45}, number = {11}, pages = {1733-1744}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77957892155&doi=10.1016%2fj.mechmachtheory.2010.06.002&partnerID=40&md5=d725c11b779822078de529a4e3cb2460}, doi = {https://doi.org/10.1016/j.mechmachtheory.2010.06.002} } |
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Gauthier, P.-A. and Pasquier, P. | Auditory tactics: A sound installation in public space using beamforming technology | 2010 | Leonardo Vol. 43(5), pp. 426-433 |
article | DOI URL |
Abstract: The term "auditory tactics" refers to the contextual listening attitudes and competencies adapted to various private and public auditory contexts, spheres and aural architectures. Auditory Tactics, created for the Pure-Data Convention 2007 in Montréal, is a spatial sound installation designed to interfere and play with the auditory tactics of passersby in a public space by projecting sounds from more private spheres. The novelty of the authors' work is the use of beamforming: a sound projection technology that allows the creation of directional sonic beams resulting in sonic illumination and shadow zones that dynamically interact with architectural surfaces. The authors report the results and lessons of this first artistic experiment with sound beams as a creative sound-projection method. © 2010 ISAST. | |||||
BibTeX:
@article{Gauthier2010426, author = {Gauthier, P.-A. and Pasquier, P.}, title = {Auditory tactics: A sound installation in public space using beamforming technology}, journal = {Leonardo}, year = {2010}, volume = {43}, number = {5}, pages = {426-433}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956975230&doi=10.1162%2fLEON_a_00034&partnerID=40&md5=10f9baf62fe582e44caabd72ebe6e615}, doi = {https://doi.org/10.1162/LEON_a_00034} } |
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Legault, J. and Atalla, N. | Sound transmission through a double panel structure periodically coupled with vibration insulators | 2010 | Journal of Sound and Vibration Vol. 329(15), pp. 3082-3100 |
article | DOI URL |
Abstract: In this paper, sound transmission through an aircraft sidewall representative double panel structure is investigated theoretically and parametric and validation studies are conducted. The studied configuration is composed of a trim panel (receiver side panel) attached to a ribbed skin panel (source side panel) with periodically spaced resilient mounts. The structure is considered infinite in order to use space harmonic expansion. The partition is also assumed planar for simplicity. The model allows for a 3D incident field and the panels can be metallic and/or composite. A four-pole formulation is employed for modeling of the mounts and the absorption provided by the fiberglass that fills the cavity between the leaves is addressed with an equivalent fluid model. The investigation of mount stiffness, damping and spacing show that properly designed mounts can increase the TL significantly (up to 20 dB of difference between rigid and resilient mounts). However, they can create undesirable resonances resulting from their interaction with the panels. The influence of cavity absorption is also studied and results illustrate the fact that it is not worth investing in a highly absorbent fiber if the structure-borne transmission path is not adequately insulated, and likewise that it is not worth investing in highly resilient mounts without sufficient cavity absorption. Moreover, the investigation of panel damping confirms that when structure-borne transmission is present, raising skin damping can increase the TL even below coincidence, but that on average, greater improvements are achieved by raising trim damping. Finally, comparison between the periodic model and finite element simulations for structure-borne transmission shows that the average level of transmitted energy is well reproduced with the periodic approach. However, the modes are only captured approximately due to the assumption of an infinite structure. © 2010 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Legault20103082, author = {Legault, J. and Atalla, N.}, title = {Sound transmission through a double panel structure periodically coupled with vibration insulators}, journal = {Journal of Sound and Vibration}, year = {2010}, volume = {329}, number = {15}, pages = {3082-3100}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77949658680&doi=10.1016%2fj.jsv.2010.02.013&partnerID=40&md5=187c18fa9bc04f6a1d5a49869fd50bff}, doi = {https://doi.org/10.1016/j.jsv.2010.02.013} } |
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Masson, P., Langlois Demers, D., Quaegebeur, N. and Micheau, P. | Chirplet-based imaging using compact piezoelectric array | 2010 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 7650(PART 1) |
conference | DOI URL |
Abstract: This paper presents the implementation of a chirplet-based matching pursuit technique called excitelet for imaging. High frequency bursts are injected into a structure by a piezoceramic (PZT) actuator and measurement is conducted by a compact array of PZT sensors, located remotely from the damage. The matching pursuit algorithm is implemented with a dictionary of atoms obtained from dispersed versions of the excitation, where the parameters of each atom are the propagation distance and the mode. For a selected point in the scan area and a given mode, the measured signal is correlated with a given atom value for each propagation path in the array configuration. A round-robin technique is used to add the contributions of all these correlation values for each point in the scan area for imaging. Simulations are first conducted for a 1.5 mm thick aluminium plate with signals synthesized for A0 mode propagating over distances corresponding to the location of a reflection or diffusion point in an area in front of an array of measurement points. The simulations show that the excitelet offers better localization of the reflection point, when compared with a group velocity-based, or time-of-flight (ToF) approach. The simulation results are validated experimentally using a 1.5 mm thick aluminium plate with a notch in the periphery of a hole. Bonded PZTs are used for both actuation and sensing of 2.5 cycles bursts at 300 kHz, 500 kHz and 850 kHz. Significant improvement of imaging quality is demonstrated with respect to classical imaging techniques. © 2010 SPIE. | |||||
BibTeX:
@conference{Masson2010, author = {Masson, P. and Langlois Demers, D. and Quaegebeur, N. and Micheau, P.}, title = {Chirplet-based imaging using compact piezoelectric array}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2010}, volume = {7650}, number = {PART 1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953516545&doi=10.1117%2f12.847791&partnerID=40&md5=9b4c9a511ba49d45172cb6c818ea9810}, doi = {https://doi.org/10.1117/12.847791} } |
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Masson, P. and Halkyard, C. | The use of time domain localized structural intensity for damage characterization | 2010 | Smart Materials and Structures Vol. 19(3) |
article | DOI URL |
Abstract: Structural intensity has been used to describe the power transferred by elastic waves through mechanical structures. In this work, the structural intensity is first expressed using the Timoshenko beam theory as an approximation to model Lamb wave propagation of the A0 and A1 modes. Simulations are conducted to illustrate localized structural intensity for a burst propagating in a semi-infinite beam with a notch represented by a thickness variation. The results show that a burst with a center frequency below the cut-off frequency of the beam propagates as a shear-dominated wave (A0 wave) while a moment-dominated burst also propagates above the cut-off frequency (A1 wave). An experimental setup for demonstrating the technique with real measurements is then presented. This consists of a 5m long notched beam, free at one end and with an anechoic termination at the other end, excited by piezoceramic transducers. Finite differences, the wavenumber Fourier transform, wave decomposition and filter synthesis are implemented to estimate the structural intensity from discrete measurements of the transverse velocity over a few centimeters using a laser vibrometer. The experimental results show that both shear and moment components of intensity can be measured for frequencies below and above the cut-off frequency and that the notch can be detected, but also indicate that care should be taken in the spacing of the measurement points due to the presence of waves of different wavelengths. © 2010 IOP Publishing Ltd. | |||||
BibTeX:
@article{Masson2010, author = {Masson, P. and Halkyard, C.R.}, title = {The use of time domain localized structural intensity for damage characterization}, journal = {Smart Materials and Structures}, year = {2010}, volume = {19}, number = {3}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-76849105766&doi=10.1088%2f0964-1726%2f19%2f3%2f035013&partnerID=40&md5=b7a6c1aa3e40203cc7e6aa83ff31f77b}, doi = {https://doi.org/10.1088/0964-1726/19/3/035013} } |
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McRae, J., Naguib, H. and Atalla, N. | Mechanical and acoustic performance of compression-molded open-cell polypropylene foams | 2010 | Journal of Applied Polymer Science Vol. 116(2), pp. 1106-1115 |
article | DOI URL |
Abstract: Open-cell materials are lightweight and multifunctional capable of absorbing acoustic energy and supporting mechanical load. The acoustic and mechanical performance of open-cell materials can be optimized through processing. in this article, the relationships between processing parameters and acoustic and mechanical performance are shown for polypropylene (PP) foams. PP foam samples are fabricated using a combined compression molding and particulate leaching process. The results from a parametric study showed that both salt size and salt to polymer ratio affect the acoustic and mechanical performance of open-cell PP foams. As salt size increases, cell size increased and cell density decreased. The salt to polymer ratio had opposite affect on cell density, and increasing the salt to polymer mass ratio increased the open-cell content. The airflow resistivity decreased significantly by increasing the cell size, which means that foam samples with smaller cell size have better sound absorption. When foam samples were thin, smaller cell sizes produced better sound absorption; however, as thickness of the sample increases, medium cell size offered the best acoustic performance. The compressive strength of the foams was increased by increasing the relative density. Acoustic performance results from the parametric study were compared to the Johnson-Allard model with good agreement. Finally, optimal cellular morphologies for acoustic absorption and mechanical performance were identified. © 2009 Wiley Periodicals, Inc. | |||||
BibTeX:
@article{McRae20101106, author = {McRae, J.D. and Naguib, H.E. and Atalla, N.}, title = {Mechanical and acoustic performance of compression-molded open-cell polypropylene foams}, journal = {Journal of Applied Polymer Science}, year = {2010}, volume = {116}, number = {2}, pages = {1106-1115}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-75449095035&doi=10.1002%2fapp.31581&partnerID=40&md5=b20a23cb48ffa5167ec0d791e367b555}, doi = {https://doi.org/10.1002/app.31581} } |
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Mejdi, A. and Atalla, N. | Dynamic and acoustic response of bidirectionally stiffened plates with eccentric stiffeners subject to airborne and structure-borne excitations | 2010 | Journal of Sound and Vibration Vol. 329(21), pp. 4422-4439 |
article | DOI URL |
Abstract: An analytical method based on the modal expansion technique was developed to predict the vibro-acoustic response of both unidirectionally and bidirectionally stiffened flat panel. This paper presents the response to diffuse acoustic field (DAF) and turbulent boundary layer (TBL) excitations in terms of their joint acceptance. Numerical results for the dynamic and acoustic responses are compared with finite element method (FEM) and boundary element (BEM) results for stiffened panel with complex and eccentrically shaped stiffeners subject to point force excitation. A theoretical prediction of the transmission loss (TL) is also compared with laboratory measurements conducted on flat panels representing aircraft models as well as with hybrid statistical energy analysis (SEA)-FEM periodic model. The results confirm that the stiffened panel has the same acoustic response as the skin without stiffeners at frequencies where the structural wavelengths are equal to the spacing between the stiffeners. In addition, the transmission loss is lowered by the presence of the stiffeners at some particular region of frequencies below the critical frequency with respect to the unstiffened panel. Crown Copyright © 2010. | |||||
BibTeX:
@article{Mejdi20104422, author = {Mejdi, A. and Atalla, N.}, title = {Dynamic and acoustic response of bidirectionally stiffened plates with eccentric stiffeners subject to airborne and structure-borne excitations}, journal = {Journal of Sound and Vibration}, year = {2010}, volume = {329}, number = {21}, pages = {4422-4439}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953622616&doi=10.1016%2fj.jsv.2010.04.007&partnerID=40&md5=53ed6e595c67e62da0e30732eb0f4f20}, doi = {https://doi.org/10.1016/j.jsv.2010.04.007} } |
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Mohamed, R. and Masson, P. | A time domain spectral element model for piezoelectric excitation of Lamb waves in isotropic plates | 2010 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 7650(PART 1) |
conference | DOI URL |
Abstract: A 2D model based on Legendre spectral element method (SEM) of a piezoceramic (PZT) patch coupled with an isotropic plate is developed in details, based on coupled linear piezoelectricity and elastodynamic equations. The simulation results are validated experimentally using a notched aluminum plate with surface bonded PZTs, for both actuation and sensing. Good agreement between simulation and experimental results is demonstrated for the fundamental Lamb modes A0 and S0, for a frequency band up to 0.75 MHz.mm on a 1.54 mm thick plate. © 2010 SPIE. | |||||
BibTeX:
@conference{Mohamed2010, author = {Mohamed, R. and Masson, P.}, title = {A time domain spectral element model for piezoelectric excitation of Lamb waves in isotropic plates}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2010}, volume = {7650}, number = {PART 1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953523658&doi=10.1117%2f12.847770&partnerID=40&md5=e31296c02f66cf39fd45dcb08b079c87}, doi = {https://doi.org/10.1117/12.847770} } |
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Neple, P., Atalla, N. and Bolduc, M. | Sound transmission through double wall aircraft structures - Mounting effect | 2010 | 24th National Conference on Noise Control Engineering 2010, Noise-Con 10, Held Jointly with the 159th Meeting of the Acoustical Society of America Vol. 2, pp. 1325-1333 |
conference | URL |
Abstract: In the context of noise control treatment definition for turbulent boundary layer excitation, the main objective of this work is to assess the impact of mechanical links on the sound transmission loss through a double wall aircraft structure. An assembly of a stiffened panel made of Composite Fiber Reinforced Plastic (with a critical frequency around 6000 Hz) and a trim panel with a honeycomb core (with a coincidence region starting around 2000 Hz) has been considered in the whole study. The transmission loss of this double panel filled with glass wool blankets has been measured under diffuse sound field and point force excitation in the [100 Hz; 10000 Hz] frequency range for a fully decoupled configuration and a totally coupled one (rigid mounting). Add-on damping patches have also been tested. Extensive simulation using transfer matrix methodology has been conducted on the double panel for different glass wool filling rates, density, sound barriers for fully decoupled and rigid configuration. The main result is that the rigid mounting decreases significantly (up to 10 dB at 1000 Hz) the double wall transmission loss compared to a fully decoupled mounting, and the acoustic efficiency for most of the passive treatments as well. | |||||
BibTeX:
@conference{Neple20101325, author = {Neple, P. and Atalla, N. and Bolduc, M.}, title = {Sound transmission through double wall aircraft structures - Mounting effect}, journal = {24th National Conference on Noise Control Engineering 2010, Noise-Con 10, Held Jointly with the 159th Meeting of the Acoustical Society of America}, year = {2010}, volume = {2}, pages = {1325-1333}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869422203&partnerID=40&md5=f16b6d105ac1b01c61c7328d5c63d5e0} } |
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Ostiguy, P.-C., Mulligan, K., Masson, P. and Elkoun, S. | Robustness of a structural health monitoring system under Drop-Weight impact loading in composites | 2010 | Annual Conference of the Prognostics and Health Management Society, PHM 2010 | conference | URL |
Abstract: In this study, the robustness of a structural health monitoring system is tested on fiber glass composite coupons under impact testing using a drop-weight impact. The composite coupons are fitted with leadzirconate- titanate (PZT) transducers to induce Lamb waves into the specimens. Robustness of the structural health monitoring system is assessed. The electrical admittance defined by the inverse of the impedance is chosen as the robustness metric and is measured using an LCR analyzer prior to, and following an impact event. Detachment of the PZT transducer is monitored through comparison of the measured electrical admittances. An average minimum composite coupon thickness of 7 mm is defined for impacting fiber glass composite coupons with pre-attached PZT transducers. A 1.5 % drop of electrical admittance was observed for that thickness for one impact. The chosen metric is related to the capability of the structural health monitoring system to provide accurate damage detection results following an impact. | |||||
BibTeX:
@conference{Ostiguy2010, author = {Ostiguy, P.-C. and Mulligan, K.R. and Masson, P. and Elkoun, S.}, title = {Robustness of a structural health monitoring system under Drop-Weight impact loading in composites}, journal = {Annual Conference of the Prognostics and Health Management Society, PHM 2010}, year = {2010}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920520620&partnerID=40&md5=84865a2f9033fe503063815dea7fc420} } |
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Quaegebeur, N., Micheau, P., Masson, P. and Maslouhi, A. | Structural health monitoring strategy for detection of interlaminar delamination in composite plates | 2010 | Smart Materials and Structures Vol. 19(8) |
article | DOI URL |
Abstract: In this paper, a structural health monitoring strategy for detecting interlaminar delamination in a carbon fiber reinforced polymer structure using Lamb waves is proposed. The delamination is simulated by inserting a Teflon tape between two transverse plies and the Lamb wave generation and measurement is enabled by using piezoceramic elements. The Lamb wave theoretical propagation and through thickness strain distribution are studied, in order to determine the optimal configuration of the final system in terms of mode and frequency selection, and piezoceramic sizing and spacing, for detection of cross-sectional delamination. Pitch and catch measurements are performed by comparing wave propagations for different frequencies and along damaged and undamaged paths of the structure, and the analysis of results is performed using the reassigned short time Fourier transform. It appears that in the low frequency range (below 300kHz), the A0 mode is sensitive to the damage, while in the high frequency range, S1 and A1 modes are both very sensitive to the damage while the propagation of the S0 mode is not affected very much. © 2010 IOP Publishing Ltd. | |||||
BibTeX:
@article{Quaegebeur2010, author = {Quaegebeur, N. and Micheau, P. and Masson, P. and Maslouhi, A.}, title = {Structural health monitoring strategy for detection of interlaminar delamination in composite plates}, journal = {Smart Materials and Structures}, year = {2010}, volume = {19}, number = {8}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954267976&doi=10.1088%2f0964-1726%2f19%2f8%2f085005&partnerID=40&md5=0f237872919999c41a4596216dc01467}, doi = {https://doi.org/10.1088/0964-1726/19/8/085005} } |
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Quaegebeur, N., Chaigne, A. and Lemarquand, G. | Transient modal radiation of axisymmetric sources: Application to loudspeakers | 2010 | Applied Acoustics Vol. 71(4), pp. 335-350 |
article | DOI URL |
Abstract: The present study proposes a transient model of the acoustic radiation of axisymmetric structures. The pressure field is approximated by the Rayleigh integral corresponding to a monopole source distribution over the non-planar vibrating surface. The displacement field is expanded on the linear modes of the structure and a change of variables in the Rayleigh integral is then proposed in the case of a monotonic profile function to compute the Spatial Impulse Response associated to each mode of vibration efficiently. The results are compared to the formulation obtained in the case of planar and spherical sources. The method of calculation is then derived in the case of a typical loudspeaker profile (association of a truncated cone with a spherical cap). Finally, the present approach is used to estimate the nonlinear radiation pattern of a prototype loudspeaker and predictions are compared to measurements in anechoic room. © 2009 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Quaegebeur2010335, author = {Quaegebeur, N. and Chaigne, A. and Lemarquand, G.}, title = {Transient modal radiation of axisymmetric sources: Application to loudspeakers}, journal = {Applied Acoustics}, year = {2010}, volume = {71}, number = {4}, pages = {335-350}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-73249118641&doi=10.1016%2fj.apacoust.2009.10.003&partnerID=40&md5=029d00986d35582a594a5166f8ea92b1}, doi = {https://doi.org/10.1016/j.apacoust.2009.10.003} } |
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Rhazi, D. and Atalla, N. | A simple method to account for size effects in the transfer matrix method | 2010 | Journal of the Acoustical Society of America Vol. 127(2), pp. EL30-EL36 |
article | DOI URL |
Abstract: The transfer matrix method based is extensively used and well-validated for predicting the transmission loss of multilayer structures. However, this method leads to poor results at low frequencies due to the infinite extent assumption it is based on. This paper presents an efficient implementation of a Rayleigh-integral based method to account for the finite size effects. The accuracy of the method is illustrated by various examples. © 2010 Acoustical Society of America. | |||||
BibTeX:
@article{Rhazi2010, author = {Rhazi, D. and Atalla, N.}, title = {A simple method to account for size effects in the transfer matrix method}, journal = {Journal of the Acoustical Society of America}, year = {2010}, volume = {127}, number = {2}, pages = {EL30-EL36}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-76349109910&doi=10.1121%2f1.3280237&partnerID=40&md5=3246d40c5154120ca6d68c9da15ccdcb}, doi = {https://doi.org/10.1121/1.3280237} } |
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Rhazi, D. and Atalla, N. | Transfer matrix modeling of the vibroacoustic response of multi-materials structures under mechanical excitation | 2010 | Journal of Sound and Vibration Vol. 329(13), pp. 2532-2546 |
article | DOI URL |
Abstract: In several automotive and aircraft applications there is a need for simple tools to assess quickly and accurately the performance of sound packages. Statistical energy analysis (SEA) and the transfer matrix method (TMM) are examples of such methods. The used methodology (for modeling sound packages) is well validated for acoustic excitations (airborne). However, a simple and reliable methodology is still lacking for mechanical excitations (structure-borne). This work concentrates on the latter. It presents and compares three different simple approaches to model the vibration and acoustic response of a mechanically excited structure with an added noise control treatment. Various examples are presented to confirm their relevance and accuracy in comparison to more exact and costly methods, such as the finite element method. In particular, it is shown that the TMM with a size correction (FTMM) is accurate enough to eliminate the classical assumption of low coupling classically assumed in SEA modeling of sound packages and/or compute efficiently the structure-borne insertion loss of sound packages used in SEA and FEM models. © 2010 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Rhazi20102532, author = {Rhazi, D. and Atalla, N.}, title = {Transfer matrix modeling of the vibroacoustic response of multi-materials structures under mechanical excitation}, journal = {Journal of Sound and Vibration}, year = {2010}, volume = {329}, number = {13}, pages = {2532-2546}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77049119426&doi=10.1016%2fj.jsv.2010.01.013&partnerID=40&md5=f3e1d2ceb82cef1b83422e517e35e563}, doi = {https://doi.org/10.1016/j.jsv.2010.01.013} } |
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Robert, R., Micheau, P., Avoine, O., Beaudry, B., Beaulieu, A. and Walti, H. | A regulator for pressure-controlled total-liquid ventilation | 2010 | IEEE Transactions on Biomedical Engineering Vol. 57(9), pp. 2267-2276 |
article | DOI URL |
Abstract: Total-liquid ventilation (TLV) is an innovative experimental method of mechanical-assisted ventilation in which lungs are totally filled and then ventilated with a tidal volume of perfluorochemical liquid by using a dedicated liquid ventilator. Such a novel medical device must resemble other conventional ventilators: it must be able to conduct controlled-pressure ventilation. The objective was to design a robust controller to perform pressure-regulated expiratory flow and to implement it on our latest liquid-ventilator prototype (Inolivent-4). Numerical simulations, in vitro experiments, and in vivo experiments in five healthy term newborn lambs have demonstrated that it was efficient to generate expiratory flows while avoiding collapses. Moreover, the in vivo results have demonstrated that our liquid ventilator can maintain adequate gas exchange, normal acidbase equilibrium, and achieve greater minute ventilation, better oxygenation and CO2 extraction, while nearing flow limits. Hence, it is our suggestion to perform pressure-controlled ventilation during expiration with minute ventilation equal or superior to 140, mL min-1kg-1 in order to ensure PaCO2 below 55 mmHg. From a clinicians point of view, pressure-controlled ventilation greatly simplifies the use of the liquid ventilator, which will certainly facilitate its introduction in intensive care units for clinical applications. © 2006 IEEE. | |||||
BibTeX:
@article{Robert20102267, author = {Robert, R. and Micheau, P. and Avoine, O. and Beaudry, B. and Beaulieu, A. and Walti, H.}, title = {A regulator for pressure-controlled total-liquid ventilation}, journal = {IEEE Transactions on Biomedical Engineering}, year = {2010}, volume = {57}, number = {9}, pages = {2267-2276}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955594730&doi=10.1109%2fTBME.2009.2031096&partnerID=40&md5=c1d88293a0a88ff218fc842645125ec9}, doi = {https://doi.org/10.1109/TBME.2009.2031096} } |
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Salissou, Y. and Panneton, R. | Wideband characterization of the complex wave number and characteristic impedance of sound absorbers | 2010 | Journal of the Acoustical Society of America Vol. 128(5), pp. 2868-2876 |
article | DOI URL |
Abstract: Several methods for measuring the complex wave number and the characteristic impedance of sound absorbers have been proposed in the literature. These methods can be classified into single frequency and wideband methods. In this paper, the main existing methods are revisited and discussed. An alternative method which is not well known or discussed in the literature while exhibiting great potential is also discussed. This method is essentially an improvement of the wideband method described by Iwase, rewritten so that the setup is more ISO 10534-2 standard-compliant. Glass wool, melamine foam and acoustical/thermal insulator wool are used to compare the main existing wideband non-iterative methods with this alternative method. It is found that, in the middle and high frequency ranges the alternative method yields results that are comparable in accuracy to the classical two-cavity method and the four-microphone transfer-matrix method. However, in the low frequency range, the alternative method appears to be more accurate than the other methods, especially when measuring the complex wave number. © 2010 Acoustical Society of America. | |||||
BibTeX:
@article{Salissou20102868, author = {Salissou, Y. and Panneton, R.}, title = {Wideband characterization of the complex wave number and characteristic impedance of sound absorbers}, journal = {Journal of the Acoustical Society of America}, year = {2010}, volume = {128}, number = {5}, pages = {2868-2876}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649597758&doi=10.1121%2f1.3488307&partnerID=40&md5=1dff487eb88b3239aabb5cd3b37eaafd}, doi = {https://doi.org/10.1121/1.3488307} } |
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Sgard, F., Nelisse, H., Atalla, N., Amedin, C. and Oddo, R. | Prediction of the acoustical performance of enclosures using a hybrid statistical energy analysis: Image source model | 2010 | Journal of the Acoustical Society of America Vol. 127(2), pp. 784-795 |
article | DOI URL |
Abstract: Enclosures are commonly used to reduce the sound exposure of workers to the noise radiated by machinery. Some acoustic predictive tools ranging from simple analytical tools to sophisticated numerical deterministic models are available to estimate the enclosure acoustical performance. However, simple analytical models are usually valid in limited frequency ranges because of underlying assumptions whereas numerical models are commonly limited to low frequencies. This paper presents a general and simple model for predicting the acoustic performance of large free-standing enclosures which is capable of taking into account the complexity of the enclosure configuration and covering a large frequency range. It is based on the statistical energy analysis (SEA) framework. The sound field inside the enclosure is calculated using the method of image sources. Sound transmission across the various elements of the enclosure is considered in the SEA formalism. The model is evaluated by comparison with existing methods and experimental results. The effect of several parameters such as enclosure geometry, panel materials, presence of noise control treatments, location of the source inside the enclosure, and presence of an opening has been investigated. The comparisons between the model and the experimental results show a good agreement for most of the tested configurations. © 2010 Acoustical Society of America. | |||||
BibTeX:
@article{Sgard2010784, author = {Sgard, F. and Nelisse, H. and Atalla, N. and Amedin, C.K. and Oddo, R.}, title = {Prediction of the acoustical performance of enclosures using a hybrid statistical energy analysis: Image source model}, journal = {Journal of the Acoustical Society of America}, year = {2010}, volume = {127}, number = {2}, pages = {784-795}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-76349113826&doi=10.1121%2f1.3273892&partnerID=40&md5=f1afab8b366e068871f5f18b8533bd5b}, doi = {https://doi.org/10.1121/1.3273892} } |
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St-Hilaire, M., Duvareille, C., Avoine, O., Carreau, A.-M., Samson, N., Micheau, P., Doueik, A. and Praud, J.-P. | Effects of postnatal smoke exposure on laryngeal chemoreflexes in newborn lambs | 2010 | Journal of Applied Physiology Vol. 109(6), pp. 1820-1826 |
article | DOI URL |
Abstract: Laryngeal chemore-flexes (LCR), which are elicited by the contact of liquids such as gastric refluxate with laryngeal mucosa, may trigger some cases of sudden infant death syndrome. Indeed, while LCR in mature mammals consist of protective responses, previous animal data have shown that LCR in immature newborns can include laryngospasm, apnea, bradycardia, and desaturation. The present study was aimed at testing the hypothesis that postnatal exposure to cigarette smoke is responsible for enhancing cardiorespiratory inhibition observed with LCR. Eight lambs were exposed to cigarette smoke (20 cigarettes/day) over 16 days and compared with seven control lambs. Urinary cotinine/creatinine ratio was measured at a level relevant to previously published levels in infants. On days 15 and 16, 0.5 ml of HCl (pH 2), milk, distilled water, or saline was injected onto the larynx via a chronic supraglottal catheter during sleep. Results showed that exposure to cigarette smoke enhanced respiratory inhibition (P < 0.05) and tended to enhance cardiac inhibition and decrease swallowing and arousal during LCR (P < 0.1). Overall, these results were observed independently of the state of alertness and the experimental solution tested. In conclusion, 16-day postnatal exposure to cigarette smoke increases cardiorespiratory inhibition and decreases protective mechanisms during LCR in nonsedated full-term lambs. Copyright © 2010 the American Physiological Society. | |||||
BibTeX:
@article{St-Hilaire20101820, author = {St-Hilaire, M. and Duvareille, C. and Avoine, O. and Carreau, A.-M. and Samson, N. and Micheau, P. and Doueik, A. and Praud, J.-P.}, title = {Effects of postnatal smoke exposure on laryngeal chemoreflexes in newborn lambs}, journal = {Journal of Applied Physiology}, year = {2010}, volume = {109}, number = {6}, pages = {1820-1826}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651305220&doi=10.1152%2fjapplphysiol.01378.2009&partnerID=40&md5=d31fc742543c8051d86f42169be4a492}, doi = {https://doi.org/10.1152/japplphysiol.01378.2009} } |
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Ahmed, M., Lee, Y., Park, C. and Atalla, N. | Effect of nanoclay on the microcellular structure and morphology of high internal phase emulsion (HIPE) foams | 2009 | Asia-Pacific Journal of Chemical Engineering Vol. 4(2), pp. 120-124 |
article | DOI URL |
Abstract: High internal phase emulsion (HIPE) polymerization foaming process is controlled for the production of novel foams with various microcellular structures and morphologies. In this study, two types of organoclay and one type of natural clay, sodium montmorillonite (NaMMT) were introduced at different concentrations to control the microcellular morphologies, cell sizes and open cell contents. A scanning electron microscopy was used to observe the microcellular morphologies and open cell contents; volume expansion ratio (VER) and cell sizes were evaluated. It was believed that the open cell contents increased as organoclay content increased, due to the lowering of the viscosity ratio of dispersed to continuous phases, as a result of adding nanoclay into the oil phase of emulsion. A correlation between the open cell content and VER that depended on clay content was attempted and the result was quite satisfactory. © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. | |||||
BibTeX:
@article{Ahmed2009120, author = {Ahmed, M.S. and Lee, Y.H. and Park, C.B. and Atalla, N.}, title = {Effect of nanoclay on the microcellular structure and morphology of high internal phase emulsion (HIPE) foams}, journal = {Asia-Pacific Journal of Chemical Engineering}, year = {2009}, volume = {4}, number = {2}, pages = {120-124}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-65249161613&doi=10.1002%2fapj.218&partnerID=40&md5=582a24fcdd24f8c3b7a7ce798d80222c}, doi = {https://doi.org/10.1002/apj.218} } |
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Allard, J. and Atalla, N. | Propagation of Sound in Porous Media: Modelling Sound Absorbing Materials | 2009 | Propagation of Sound in Porous Media: Modelling Sound Absorbing Materials, pp. 1-358 | book | DOI URL |
Abstract: "The first edition of this book is considered the bible of this topic... Suffice it to say that there is no other published treatise that approaches the depth of treatment offered by this book. The coverage is the state of the published art, while the added contents cover the new known developments in the field." Haisam Osman; Technology Development Manager, United Launch Alliance. This long-awaited second edition of a respected text from world leaders in the field of acoustic materials covers the state of the art with a depth of treatment unrivalled elsewhere. Allard and Atalla employ a logical and progressive approach that leads to a thorough understanding of porous material modelling. The first edition of Propagation of Sound in Porous Media introduced the basic theory of acoustics and the related techniques. Research and development in sound absorption has however progressed significantly since the first edition, and the models and methods described, at the time highly technical and specialized, have since become main stream. In this second edition, several original topics have been revisited and practical prediction methods and industrial applications have been added that increase the breadth of its appeal to both academics and practising engineers. New chapters have also been added on numerical modeling in both low (finite element) and high frequency (Transfer Matrix Method). Collating 'must-have' information for engineers working in sound and vibration, Propagation of Sound in Porous Media, 2nd edition offers an indisputable reference to a diverse audience; including graduate students and academics in mechanical & civil engineering, acoustics and noise control, as well as practising mechanical, chemical and materials engineers in the automotive, rail, aerospace, building and civil industries. © 2009 John Wiley & Sons, Ltd. | |||||
BibTeX:
@book{Allard20091, author = {Allard, J.F. and Atalla, N.}, title = {Propagation of Sound in Porous Media: Modelling Sound Absorbing Materials}, journal = {Propagation of Sound in Porous Media: Modelling Sound Absorbing Materials}, year = {2009}, pages = {1-358}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84890254825&doi=10.1002%2f9780470747339&partnerID=40&md5=7964a1cfff63dff4d1037178962fb298}, doi = {https://doi.org/10.1002/9780470747339} } |
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Amichi, K. and Atalla, N. | A new 3D finite element for sandwich beams with a viscoelastic core | 2009 | Journal of Vibration and Acoustics, Transactions of the ASME Vol. 131(2), pp. 0210101-0210109 |
article | DOI URL |
Abstract: A sandwich finite element for laminated steels is presented. It is based on a discrete displacement approach and allows for both symmetrical and unsymmetrical configurations. The three-layer sandwich model is built assuming a Timoshenko hypothesis for the viscoelastic core and Euler-Bernoulli hypotheses for the elastic faces, but the latter is modified to account for the rotational influence of the transversal shearing in the core. The validity and accuracy of the presented element are assessed through comparisons with numerical results of sandwich beams and sandwich rings with a variety of geometrical and mechanical properties and various boundary conditions. The present results are also compared with analytical, finite element, and experimental solutions for various boundary conditions. © 2009 by ASME. | |||||
BibTeX:
@article{Amichi20090210101, author = {Amichi, K. and Atalla, N.}, title = {A new 3D finite element for sandwich beams with a viscoelastic core}, journal = {Journal of Vibration and Acoustics, Transactions of the ASME}, year = {2009}, volume = {131}, number = {2}, pages = {0210101-0210109}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955226004&doi=10.1115%2f1.3025828&partnerID=40&md5=5b84f47f74485a92cb142891ef03f201}, doi = {https://doi.org/10.1115/1.3025828} } |
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Amichi, K. and Atalla, N. | Vibro-acoustics behaviour of laminated steel panels with sound package components | 2009 | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 Vol. 4, pp. 2899-2907 |
conference | URL |
Abstract: Noise and vibrations control is a major concern in several industry fields such as aeronautics and automobile. Noise control materials, such us fibrous and foams, are often combined to form a multilayer treatment. Such materials can offer remarkable performance advantages over a wide range of operating frequencies, especially when combined with damped sandwich panels with thin layer of viscoelastic core (Metal/Polymer/Metal: MPM). The later, are widely used to reduce noise and vibration and to improve interior sound quality. An appropriate selection of a multilayer treatment often can help to control both noise and vibration by blocking, redirecting, and absorbing the airborne sound energy and reducing the structural vibration. The growing use of such structures has motivated many authors to intensify the study of the vibro-acoustic behaviours and the design applications of such structures. The objective of the paper is to compare the performance of the typical automotive sound package components attached to steel vs MPS panels. Using finite element based numerical simulations, air-borne and structure-borne sound insertion-loss are used in parallel to assess the sound package performance. | |||||
BibTeX:
@conference{Amichi20092899, author = {Amichi, K. and Atalla, N.}, title = {Vibro-acoustics behaviour of laminated steel panels with sound package components}, journal = {38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009}, year = {2009}, volume = {4}, pages = {2899-2907}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870035900&partnerID=40&md5=87de7ee98d3f2d242f40894fcec6bac1} } |
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Amichi, K., Atalla, N. and Ruokolainen, R. | An efficient sandwich plate element for predicting the vibro-acoustic response of laminated steel panels | 2009 | 2008 Proceedings of the NoiseCon/ASME NCAD, NCAD 2008, pp. 391-398 | conference | URL |
Abstract: A New finite element sandwich plate is presented. It is based on discrete displacement approach and allows for both symmetrical and unsymmetrical configurations. The validity and accuracy of the presented element is assessed through comparisons with both tests and classical FE modeling. The tests consist of various configurations of sandwich panels in a coupled plate-cavity system. A parametric study, using the developed element, is finally presented to highlights the effects of skin and core properties on the vibration and radiation of such structures under both airborne and structure-borne excitations. Copyright © 2008 ASME and General Motors. | |||||
BibTeX:
@conference{Amichi2009391, author = {Amichi, K. and Atalla, N. and Ruokolainen, R.}, title = {An efficient sandwich plate element for predicting the vibro-acoustic response of laminated steel panels}, journal = {2008 Proceedings of the NoiseCon/ASME NCAD, NCAD 2008}, year = {2009}, pages = {391-398}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349869502&partnerID=40&md5=ed2f40486bbc9f27df24fc2d3f2667c4} } |
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Atalla, N. and Ghinet, S. | Modeling the sound transmission through sandwich-composite structures with attached noise control materials | 2009 | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 Vol. 3, pp. 1813-1824 |
conference | URL |
Abstract: This paper discusses the prediction of the transmission loss of sandwich-composite panels. It presents the main ideas behind two impedance models and explains how these models are used to predict the transmission loss of sandwich-composite models. The use of the models to predict other important vibroacoustic indicators such as the modal density and the radiation efficiency is also discussed together with the approach to account for a sound package using the transfer matrix method. | |||||
BibTeX:
@conference{Atalla20091813, author = {Atalla, N. and Ghinet, S.}, title = {Modeling the sound transmission through sandwich-composite structures with attached noise control materials}, journal = {38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009}, year = {2009}, volume = {3}, pages = {1813-1824}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870042494&partnerID=40&md5=5b7e972467a881400135d96205650331} } |
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Bavu, E. and Berry, A. | High-resolution imaging of sound sources in free field using a numerical time-reversal sink | 2009 | Acta Acustica united with Acustica Vol. 95(4), pp. 595-606 |
article | DOI URL |
Abstract: Numerous practical applications - such as non destructive evaluation of industrial structures, acoustic characterization of musical instruments, and acoustic mapping of sound sources in a known propagation medium - involve source detection and characterization. In the past, this problem has been investigated using different beamforming and backpropagation methods. In this work, a new technique, based on the time reversal sink concept, is used to detect active sound sources with a limited number of measurement points. The theory and application of super-resolution focusing of sound and vibration using a time-reversal sink (TRS) have been studied, both in ultrasonic regime and in audible range. A high-resolution imaging technique based on a numerical time reversal sink has recently been developed by the authors for vibrational imaging of active sources in a dispersive medium. In this paper, the numerical time reversal sink imaging technique is adapted to the case of high-resolution acoustic imaging of active sound sources in a three-dimensional free field. This technique allows high-resolution imaging and provides a new method of characterization and detection of sound sources. All results show the high resolution imaging capabilities of this new technique when compared with classical time-reversal (TR) backpropagation. More than simply detecting the position of the acoustic source, this technique allows to detect the size of the active sources. This technique provides an alternative to other imaging and source detection techniques, such as three-dimensional acoustic holography and beamforming. © S. Hirzel Verlag · EAA. | |||||
BibTeX:
@article{Bavu2009595, author = {Bavu, E. and Berry, A.}, title = {High-resolution imaging of sound sources in free field using a numerical time-reversal sink}, journal = {Acta Acustica united with Acustica}, year = {2009}, volume = {95}, number = {4}, pages = {595-606}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-68849094972&doi=10.3813%2fAAA.918188&partnerID=40&md5=324c3faa562281c04cf100ee498822a6}, doi = {https://doi.org/10.3813/AAA.918188} } |
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Belanger, P., Berry, A., Pasco, Y., Robin, O., St-Amant, Y. and Rajan, S. | Multi-harmonic active structural acoustic control of a helicopter main transmission noise using the principal component analysis | 2009 | Applied Acoustics Vol. 70(1), pp. 153-164 |
article | DOI URL |
Abstract: This paper evaluates the feasibility and effectiveness, under controlled conditions, of active structural acoustic control of a helicopter main transmission in order to attenuate the vibration of the receiving roof panel and its sound radiation into the cabin. The vibroacoustic analysis of a typical helicopter drive train is conducted to extract the dominant tones generated by the various transmission stages. A finite element model of a Bell 407 transmission and simplified roof structure is developed in order to investigate various active control arrangements using piezoceramic actuators to control wave propagation in the gearbox supporting struts or receiving panel. The principal component analysis is used to extract the most significant control paths and reduce the control effort. A multiple frequency principal component least mean square (PC-LMS) algorithm is implemented on a laboratory setup and is used to successfully reduce up to seven gearbox tones simultaneously. © 2007 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Belanger2009153, author = {Belanger, P. and Berry, A. and Pasco, Y. and Robin, O. and St-Amant, Y. and Rajan, S.}, title = {Multi-harmonic active structural acoustic control of a helicopter main transmission noise using the principal component analysis}, journal = {Applied Acoustics}, year = {2009}, volume = {70}, number = {1}, pages = {153-164}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-55049099699&doi=10.1016%2fj.apacoust.2007.12.007&partnerID=40&md5=61fa845827fde312960d5a04211f46aa}, doi = {https://doi.org/10.1016/j.apacoust.2007.12.007} } |
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Buaka Muanke, P., Micheau, P. and Masson, P. | Nonlinear phase shift control of semi-active friction devices for optimal energy dissipation | 2009 | Journal of Sound and Vibration Vol. 320(1-2), pp. 16-28 |
article | DOI URL |
Abstract: Semi-active friction devices are usually designed to dissipate the vibratory energy in a mechanical system by controlling a dry friction interface. When the normal force applied on the friction interface is controlled by a feedback loop, the design of an optimized compensator is challenging due to the complexity of the nonlinear behavior of the dry friction. Usually, with some simplifications, a nonlinear feedback controller can be designed either by the Lyapunov method or by the feedback linearization approach. This paper investigates the interest of narrow-band filtering and phase shift compensation in such nonlinear feedback controllers when the system is excited by an external harmonic force. The complex envelope approach is used to implement the narrow-band filtering with an adjustable phase shift compensation within the nonlinear controllers. Experiments are conducted to validate the control approaches using a friction device composed of two piezoelectric stack actuators, each one applying a normal force on a friction pad in order to stop the movement of a mobile mass excited by a sinusoidal force. The experimental results show that for a proper choice of the phase shift compensation, the sticking period per cycle is reduced, and consequently the power dissipation is increased. © 2008 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{BuakaMuanke200916, author = {Buaka Muanke, P. and Micheau, P. and Masson, P.}, title = {Nonlinear phase shift control of semi-active friction devices for optimal energy dissipation}, journal = {Journal of Sound and Vibration}, year = {2009}, volume = {320}, number = {1-2}, pages = {16-28}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-57349185703&doi=10.1016%2fj.jsv.2008.08.002&partnerID=40&md5=ed3758176dd49fb8428f9232c8680434}, doi = {https://doi.org/10.1016/j.jsv.2008.08.002} } |
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Chu, R., Naguib, H. and Atalla, N. | Synthesis and characterization of open-cell foams forsound absorption with rotational molding method | 2009 | Polymer Engineering and Science Vol. 49(9), pp. 1744-1754 |
article | DOI URL |
Abstract: Foams with open-cell structures have improved sound absorption abilities over conventional closed-cell foams. One technique to optimize the acoustic abilities of open-cell foams is to control their cellular properties through the manipulation of processing parameters. This article presents a novel process to synthesize open-cell polymeric foams for acoustic applications. The process combined rotational foam molding and particulate leaching to produce foams with open-cell networks that are desirable for acoustic absorption. Open-cell foams with open-porosity of about 0.90 were successfully fabricated with this combined foaming process. Effects of processing parameters on the cellular and acoustic properties of the foam samples were examined and discussed. On the basis of the results from the study, the cellular and acoustic properties of the foam fabricated from the proposed method can be controlled through the use of different salt particle sizes in the process. © 2009 Society of Plastics Engineers. | |||||
BibTeX:
@article{Chu20091744, author = {Chu, R.K.M. and Naguib, H.E. and Atalla, N.}, title = {Synthesis and characterization of open-cell foams forsound absorption with rotational molding method}, journal = {Polymer Engineering and Science}, year = {2009}, volume = {49}, number = {9}, pages = {1744-1754}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-68949176798&doi=10.1002%2fpen.21412&partnerID=40&md5=bf96504cb8519b693e5f3af702267aef}, doi = {https://doi.org/10.1002/pen.21412} } |
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Cintosun, E., Stecenko, T. and Atalla, N. | Numerical performance comparison of viscoelastic material damping to equivalent mass as acoustic treatments to aircraft fuselage structure under various excitations | 2009 | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 Vol. 4, pp. 2673-2681 |
conference | URL |
Abstract: A numerical acoustic comparison of viscoelastic material damping to equivalent mass was performed. Transfer Matrix Method (TMM) and Finite Element Method (FEM) were used to perform the numerical analysis. Viscoelastic material damping and equivalent mass were compared as treatments to representative aircraft fuselage structure as part of sound packages. The sound packages were made up of either fiberglass or foam in addition to viscoelastic material damping or equivalent mass. The viscoelastic material damping used in this study is constraining layer damping and abbreviated as CLD. The mechanical properties of CLD at its optimal performing temperature of -40 C were used in the numerical analysis. The equivalent mass was modeled as a solid material with the same surface weight of CLD. As part of the analysis, representative aircraft fuselage structure with and without acoustic treatment was subjected to diffuse acoustic field and point force mechanical excitations. Two different fuselage structures were modeled: one made up of Aluminum, a typical aircraft fuselage structure; and the other one, a carbon composite structure. Calculated acoustic responses of insertion loss (IL), mean quadratic velocity (MQV) and structural borne insertion loss (SBIL) are used to quantitatively categorize acoustic treatments under various excitations. | |||||
BibTeX:
@conference{Cintosun20092673, author = {Cintosun, E. and Stecenko, T. and Atalla, N.}, title = {Numerical performance comparison of viscoelastic material damping to equivalent mass as acoustic treatments to aircraft fuselage structure under various excitations}, journal = {38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009}, year = {2009}, volume = {4}, pages = {2673-2681}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870023852&partnerID=40&md5=9d01688f2f7f88c61999d29733801e5b} } |
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Costantino, M., Micheau, P., Shaffer, T., Tredici, S. and Wolfson, M. | Clinical design functions: Round table discussions on the bioengineering of liquid ventilators | 2009 | ASAIO Journal Vol. 55(3), pp. 206-208 |
article | DOI URL |
Abstract: During the 6th International Symposium on Perfluorocarbon Application and Liquid Ventilation, a round table discussion on bioengineering was held in which different experts shared their opinions and experiences about the use of a total liquid ventilator design for clinical applications. To structure the discussion, all experts were invited to contribute their knowledge within the context of three matrixes related to the liquid ventilators: 1) function and technology, 2) ventilation modes, and 3) risk analyses. The outcome of this international conference recommends continued development of a total liquid ventilator toward clinical applications. ©2009Amercian Society of Artificial Internal Organs. | |||||
BibTeX:
@article{Costantino2009206, author = {Costantino, M.L. and Micheau, P. and Shaffer, T.H. and Tredici, S. and Wolfson, M.R.}, title = {Clinical design functions: Round table discussions on the bioengineering of liquid ventilators}, journal = {ASAIO Journal}, year = {2009}, volume = {55}, number = {3}, pages = {206-208}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67650400221&doi=10.1097%2fMAT.0b013e318199c167&partnerID=40&md5=d416a86c9713aa0eaad7796525c7efcc}, doi = {https://doi.org/10.1097/MAT.0b013e318199c167} } |
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Couillard, M., Masson, P. and Micheau, P. | Identification of friction parameters for limited relative displacement contacts | 2009 | Shock and Vibration Vol. 16(5), pp. 481-493 |
article | DOI URL |
Abstract: Damping using dry friction has long been recognized as an effective control method for many vibration problems. However, given the strong nonlinear nature of friction, the theoretical and experimental investigations of associated non-linear control methods are much more difficult than for linear control methods. Moreover, the difficulty of identifying friction models parameters for Limited Relative Displacement (LRD) contacts is still a subject of research. This study first proposes an identification procedure to evaluate the ability of the LuGre friction model to predict small amplitude (30 µm-150 µm) frictionally damped vibrations for a LRD contact. An experimental setup implementing an ideal frictionally damped Single Degree Of Freedom (SDOF) oscillator connected to an electrodynamic shaker is then presented to study friction damping. The simulation results are assessed against the experimental results, demonstrating that the identification procedure is well suited to estimate the parameters of the LuGre friction model and that the model captures very well the friction phenomenon for small amplitude vibrations. © 2009 - IOS Press and the authors. All rights reserved. | |||||
BibTeX:
@article{Couillard2009481, author = {Couillard, M. and Masson, P. and Micheau, P.}, title = {Identification of friction parameters for limited relative displacement contacts}, journal = {Shock and Vibration}, year = {2009}, volume = {16}, number = {5}, pages = {481-493}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349143113&doi=10.3233%2fSAV-2009-0482&partnerID=40&md5=975f9ec503c8d4bb2e9c7ac2439cf3a6}, doi = {https://doi.org/10.3233/SAV-2009-0482} } |
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Dhifaoui, H., Atalla, N., Panneton, R. and Amedin, C. | A non-linear impedance model for acoustic liners | 2009 | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 Vol. 5, pp. 2964-2971 |
conference | URL |
Abstract: Acoustic treatments are extensively used in commercial gas turbine engine nacelle system to reduce aircraft noise in flight by providing appropriate impedance boundary conditions. Current single degree of freedom liners typically possess a perforated face sheet backed by honeycomb cells and rigid plate. These liners exhibit nonlinear impedance characteristics that are usually parameterized as a function of sound pressure level (SPL). At high sound pressure levels, the resistance and reactance are modified to account for nonlinear effects. In this paper, such a model is presented and compared to three classical acoustic impedance models, namely Herch's, GE's and Crandall's. Normal incidence impedance measurements, on both 1 SDOF systems, in a high intensity impedance tube, are presented to corroborate the validity of the developed model. | |||||
BibTeX:
@conference{Dhifaoui20092964, author = {Dhifaoui, H. and Atalla, N. and Panneton, R. and Amedin, C.K.}, title = {A non-linear impedance model for acoustic liners}, journal = {38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009}, year = {2009}, volume = {5}, pages = {2964-2971}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870009859&partnerID=40&md5=e213759c84d590f678df9c28d6926a97} } |
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Dorel, S., Drouet, J.-M., Couturier, A., Champoux, Y. and Hug, F. | Changes of pedaling technique and muscle coordination during an exhaustive exercise | 2009 | Medicine and Science in Sports and Exercise Vol. 41(6), pp. 1277-1286 |
article | DOI URL |
Abstract: PURPOSE:: Alterations of the mechanical patterns during an exhaustive pedaling exercise have been previously shown. We designed the present study to test the hypothesis that these alterations in the biomechanics of pedaling, which occur during exhaustive exercise, are linked to changes in the activity patterns of lower limb muscles. METHODS:: Ten well-trained cyclists were tested during a limited time to exhaustion, performing 80% of maximal power tolerated. Pedal force components were measured continuously using instrumented pedals and were synchronized with surface EMG signals measured in 10 lower limb muscles. RESULTS:: The results confirmed most of the alterations of the mechanical patterns previously described in the literature. The magnitude of the root mean squared of the EMG during the complete cycle (RMScycle) for tibialis anterior and gastrocnemius medialis decreased significantly (P < 0.05) from 85% and 75% of Tlim, respectively. A higher RMScycle was obtained for gluteus maximus (P < 0.01) and biceps femoris (P < 0.05) from 75% of Tlim. The k values that resulted from the cross-correlation technique indicated that the activities of six muscles (gastrocnemius medialis, gastrocnemius lateralis, tibialis anterior, vastus lateralis, vastus medialis, and rectus femoris) were shifted forward in the cycle at the end of the exercise. CONCLUSIONS:: The large increases in activity for gluteus maximus and biceps femoris, which are in accordance with the increase in force production during the propulsive phase, could be considered as instinctive coordination strategies that compensate for potential fatigue and loss of force of the knee extensors (i.e., vastus lateralis and vastus medialis) by a higher moment of the hip extensors. | |||||
BibTeX:
@article{Dorel20091277, author = {Dorel, S. and Drouet, J.-M. and Couturier, A. and Champoux, Y. and Hug, F.}, title = {Changes of pedaling technique and muscle coordination during an exhaustive exercise}, journal = {Medicine and Science in Sports and Exercise}, year = {2009}, volume = {41}, number = {6}, pages = {1277-1286}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67650080476&doi=10.1249%2fMSS.0b013e31819825f8&partnerID=40&md5=f477fd029cdc1accf21913a01c3d6d3b}, doi = {https://doi.org/10.1249/MSS.0b013e31819825f8} } |
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Francoeur, D., Micheau, P. and Masson, P. | Parametric identification of a transmission line model for in situ damage characterization in lap joints | 2009 | Smart Materials and Structures Vol. 18(4) |
article | DOI URL |
Abstract: This paper presents an in situ damage identification method to characterize the thickness and location of a notch in a one-dimensional lap joint. The approach uses the propagation of flexural waves generated by a piezoceramic (PZT) to evaluate the global reflection coefficient of a complex structure such as a lap joint. A transmission line model (TLM) is used to describe the theoretical reflection coefficient from healthy and damaged lap joints. Parameters from the lap joint are identified in two steps from the experimental measurement of the reflection coefficient. The first step is a calibration step which gives, for the healthy lap joint, the length of the lap joint and distance between the measurement point and the lap joint. The identification of these parameters is performed by minimizing a cost function evaluated for different combinations of parameters. The second step allows us to obtain the parameters associated with the notch, which are its location and thickness. Several cases of healthy and damaged lap joints are conducted and very good results are achieved for the identification of the parameters. © 2009 IOP Publishing Ltd. | |||||
BibTeX:
@article{Francoeur2009, author = {Francoeur, D. and Micheau, P. and Masson, P.}, title = {Parametric identification of a transmission line model for in situ damage characterization in lap joints}, journal = {Smart Materials and Structures}, year = {2009}, volume = {18}, number = {4}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-68549096382&doi=10.1088%2f0964-1726%2f18%2f4%2f045005&partnerID=40&md5=3744f3275ff58044368834be5f4a7f9a}, doi = {https://doi.org/10.1088/0964-1726/18/4/045005} } |
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Francoeur, D., Masson, P. and Micheau, P. | Sensitivity analysis of a transmission line model for damage characterization in complex structures | 2009 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 7295 |
conference | DOI URL |
Abstract: With the goal to detect relatively small damage while minimizing signal processing burden, an approach in the medium frequency range (10 kHz - 50 kHz) is proposed for the characterization of a damage in a complex assembly structure and more specifically, a lap joint. The approach is based on the identification of the parameters of a reference transmission line model of a damaged lap joint structure through the experimental measurement of a reflection coefficient. The transmission line model of the lap joint is first presented, where symmetrical thickness variations on a beam are used to represent the lap joint region and a notch within this region. The cost function used in the model identification approach is then defined as the squared difference between simulated and measured reflection coefficients in a given frequency range. A sensitivity analysis is conducted using the Hessian of the cost function and simulation results are presented to demonstrate the sensitivity of the cost function to variations in the sought parameters, i.e. location and depth of the notch, in the frequency domain. Experimental results are then presented to assess the sensitivity of the cost function to the variation of the depth of the notch. These experimental results confirm the simulation results which indicate that the sensitivity of the cost function to the depth of the notch increases as this depth increases. Moreover, cross-sensitivity results indicate that the sensitivity of the cost function to the location of the notch also increases as the depth of the notch increases. © 2009 SPIE. | |||||
BibTeX:
@conference{Francoeur2009, author = {Francoeur, D. and Masson, P. and Micheau, P.}, title = {Sensitivity analysis of a transmission line model for damage characterization in complex structures}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2009}, volume = {7295}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-66749156705&doi=10.1117%2f12.811935&partnerID=40&md5=cb79758d9cad615286f1f9e7a01b9b99}, doi = {https://doi.org/10.1117/12.811935} } |
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Gérard, A., Berry, A., Masson, P. and Gervais, Y. | Modelling of tonal noise control from subsonic axial fans using flow control obstructions | 2009 | Journal of Sound and Vibration Vol. 321(1-2), pp. 26-44 |
article | DOI URL |
Abstract: This paper investigates the analytical calculation of blade unsteady lift spectrum when interacting with a neighboring obstruction, designed to control tonal noise. The approach used in this paper is to add a secondary unsteady lift mode, of equal intensity but opposite in phase with the primary unsteady lift mode which radiates most of tonal noise, so that the resultant of both primary and secondary modes is null. To control one unsteady lift mode (consequently an acoustic tone) without affecting the harmonics of the controlled mode (consequently the harmonics of the acoustic tone to be controlled), it is important for the secondary unsteady lift to be harmonically selective. We have therefore evaluated the harmonic content of the blade unsteady lift generated by the proposed control obstructions. To this purpose, an original equation is derived using the infinitesimal radial strips theory coupled with the one-dimensional Sears gust analysis. The spectrum of the blade unsteady lift is then analyzed for three types of obstructions: a series of B-trapezoidal obstructions, a B-periodic sinusoidal obstruction and a series of B-rectangular obstructions (where B is the number of blades). The use of salient obstructions leads to a large unsteady lift harmonic content. An optimized wake width of the trapezoidal obstruction leads to a low harmonic content rate of 5.5 %. A Gaussian approximation of the measured inflow velocity profile generated by a sinusoidal obstruction leads to a relatively low harmonic content rate of 18.8 %, which indicates that most of the energy is contained in the fundamental mode of the blade unsteady lift. Finally, a rotor/rectangular interaction shows that the use of small-width rectangular obstructions leads to a higher harmonic content rate of 58.6 %. © 2008 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Gérard200926, author = {Gérard, A. and Berry, A. and Masson, P. and Gervais, Y.}, title = {Modelling of tonal noise control from subsonic axial fans using flow control obstructions}, journal = {Journal of Sound and Vibration}, year = {2009}, volume = {321}, number = {1-2}, pages = {26-44}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-59649096436&doi=10.1016%2fj.jsv.2008.09.027&partnerID=40&md5=d5edaf30d70568e20f616354aa8a2765}, doi = {https://doi.org/10.1016/j.jsv.2008.09.027} } |
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Gérard, A., Berry, A., Masson, P. and Gervais, Y. | Experimental validation of tonal noise control from subsonic axial fans using flow control obstructions | 2009 | Journal of Sound and Vibration Vol. 321(1-2), pp. 8-25 |
article | DOI URL |
Abstract: This paper presents the acoustic performance of a novel approach for the passive adaptive control of tonal noise radiated from subsonic fans. Tonal noise originates from non-uniform flow that causes circumferentially varying blade forces and gives rise to a considerably larger radiated dipolar sound at the blade passage frequency (BPF) and its harmonics compared to the tonal noise generated by a uniform flow. The approach presented in this paper uses obstructions in the flow to destructively interfere with the primary tonal noise arising from various flow conditions. The acoustic radiation of the obstructions is first demonstrated experimentally. Indirect on-axis acoustic measurements are used to validate the analytical prediction of the circumferential spectrum of the blade unsteady lift and related indicators generated by the trapezoidal and sinusoidal obstructions presented in Ref. [A. Gérard, A. Berry, P. Masson, Y. Gervais, Modelling of tonal noise control from subsonic axial fans using flow control obstructions, Journal of Sound and Vibration (2008), this issue, doi:10.1016/j.jsv.2008.09.027.] and also by cylindrical obstructions used in the literature. The directivity and sound power attenuation are then given in free field for the control of the BPF tone generated by rotor/outlet guide vane (OGV) interaction and the control of an amplified BPF tone generated by the rotor/OGV interaction with an added triangular obstruction between two outlet guide vanes to enhance the primary non-uniform flow. Global control was demonstrated in free field, attenuation up to 8.4 dB of the acoustic power at BPF has been measured. Finally, the aerodynamic performances of the automotive fan used in this study are almost not affected by the presence of the control obstruction. © 2008 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Gérard20098, author = {Gérard, A. and Berry, A. and Masson, P. and Gervais, Y.}, title = {Experimental validation of tonal noise control from subsonic axial fans using flow control obstructions}, journal = {Journal of Sound and Vibration}, year = {2009}, volume = {321}, number = {1-2}, pages = {8-25}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-59649122811&doi=10.1016%2fj.jsv.2008.09.019&partnerID=40&md5=8d061aab3bb41db0f568808ba4bf0a49}, doi = {https://doi.org/10.1016/j.jsv.2008.09.019} } |
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Legault, J. and Atalla, N. | Transmission loss through mounts connected double wall lightweight structures | 2009 | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 Vol. 4, pp. 2690-2698 |
conference | URL |
Abstract: This paper integrates four-pole method formulations describing trim mounts dynamic behavior in the modeling of sound transmission through lightweight aeronautic-like double panel structures. The trim (interior panel) is attached to ring frames that are ribbed to the skin (exterior panel) through periodically spaced resilient mounts. For simplicity, the structure is considered infinite and flat, but a full 3D incident field is allowed and the absorption provided by the fiberglass filling the cavity between the leaves is addressed with an equivalent fluid model. The model also allows the panels to be metallic and/or composite. Simulation results are presented for both types of structures. By using trim mounts, structureborne sound is reduced at mid and high frequencies (f > 300 Hz) and simulation results show that the gain in transmission loss they can potentially provide varies from 3 to 15 dB depending on the frequency. | |||||
BibTeX:
@conference{Legault20092690, author = {Legault, J. and Atalla, N.}, title = {Transmission loss through mounts connected double wall lightweight structures}, journal = {38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009}, year = {2009}, volume = {4}, pages = {2690-2698}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870015330&partnerID=40&md5=3e4b757138f93f2669d937b5a552a912} } |
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Legault, J. and Atalla, N. | Numerical and experimental investigation of the effect of structural links on the sound transmission of a lightweight double panel structure | 2009 | Journal of Sound and Vibration Vol. 324(3-5), pp. 712-732 |
article | DOI URL |
Abstract: This paper examines various models predicting the influence of periodically spaced structural links on sound transmission through lightweight double panel structures. A baseline configuration made up from two aluminum plates connected through aluminum C-section channels and a fiberglass filled cavity has been specifically built and its TL measured for comparison and validation of the investigated models. First, classical decoupled approaches are outlined and adapted for the studied case. Next, a periodic model based on existing formulations is presented. The model allows for a 3D incident field and accounts for the absorption in the cavity with the help of an equivalent fluid model for the fiberglass. Three cases of coupling conditions are considered for the links: a mass-spring-mass approximation, a beam-type approximation and a beam-type approximation where the rigidity and the inertia of the beams are neglected. The measurements show that the bridged configuration strongly reduces the TL at mid and high frequency and exhibits pass/stop bands characteristic of periodic structures. The predictions of decoupled approaches capture the physics of the problem only approximately and with the integration of the mass of the connectors in the context of thin lightweight panels, their agreement with experimental data is further reduced. On the other hand, the results obtained with the periodic model are excellent over most of the studied frequency range. However, in the vicinity of the critical frequency of the thicker panel (around 6 kHz), an overestimation of the TL is observed. This suggests that the model will have to account better for damping and resonant transmission. © 2009 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Legault2009712, author = {Legault, J. and Atalla, N.}, title = {Numerical and experimental investigation of the effect of structural links on the sound transmission of a lightweight double panel structure}, journal = {Journal of Sound and Vibration}, year = {2009}, volume = {324}, number = {3-5}, pages = {712-732}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349284289&doi=10.1016%2fj.jsv.2009.02.019&partnerID=40&md5=1e1a97768e3c30758ca6a687c1a24d4a}, doi = {https://doi.org/10.1016/j.jsv.2009.02.019} } |
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Leroy, P., Atalla, N., Berry, A. and Herzog, P. | Three dimensional finite element modeling of smart foam | 2009 | Journal of the Acoustical Society of America Vol. 126(6), pp. 2873-2885 |
article | DOI URL |
Abstract: The "smart foam" concept and design originate from the combination of the passive dissipation capability of foam in the medium and high frequency ranges and the active absorption ability of piezoelectric actuator (generally polyvinylidene fluoride) in the low frequency range. This results into a passive/active absorption control device that can efficiently operate over a broad range of frequencies. In this paper, a full three dimensional finite element model of smart foam is presented including its experimental validation. The modeling tool uses quadratic poroelastic elements, as well as elastic, fluid, and piezoelectric elements. The weak integral formulation of the different media involved is presented with the associated coupling conditions. A simplified orthotropic model of poroelastic media is presented. To validate the developed model, a prototype of a smart foam has been realized and its passive absorption and radiation measured in an impedance tube and compared to predictions. The experimental validation demonstrates the validity of the model. This modeling tool constitutes a general platform to simulate and optimize various configurations of smart foams. © 2009 Acoustical Society of America. | |||||
BibTeX:
@article{Leroy20092873, author = {Leroy, P. and Atalla, N. and Berry, A. and Herzog, P.}, title = {Three dimensional finite element modeling of smart foam}, journal = {Journal of the Acoustical Society of America}, year = {2009}, volume = {126}, number = {6}, pages = {2873-2885}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-72549113593&doi=10.1121%2f1.3238241&partnerID=40&md5=c4556a57fa65763a40ea71652cfb321d}, doi = {https://doi.org/10.1121/1.3238241} } |
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Manning, J. and Panneton, R. | Establishing relationships between acoustic and physical properties of shoddy-based fibre absorbers | 2009 | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 Vol. 2, pp. 1044-1049 |
conference | URL |
Abstract: Post industrial recycled fibres or "shoddies" have found widespread use in the production of fibrous sound absorbers but they are not easily characterized due to the variability of the fibres present. This paper presents the results of acoustic and physical property testing on fibrous absorbers composed in whole or in part by shoddies. Testing was completed on various different shoddy constructions processed by three different methods: thermal bonding, chemical bonding, and mechanical bonding. The parameters measured were: open porosity, static airflow resistivity, bulk density, Young's modulus and structural loss factor. Furthermore, empirical relationships between acoustic properties and measured physical properties, such as bulk density and porosity are presented. A relationship between airflow resistivity and bulk density using a modified Bies- Hansen formulation is also proposed. The more complex acoustical models require several material properties that may be difficult to measure. It is anticipated that the above relationships can be used to reduce the amount and difficulty of testing required when employing an appropriate acoustic model. | |||||
BibTeX:
@conference{Manning20091044, author = {Manning, J. and Panneton, R.}, title = {Establishing relationships between acoustic and physical properties of shoddy-based fibre absorbers}, journal = {38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009}, year = {2009}, volume = {2}, pages = {1044-1049}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870015326&partnerID=40&md5=2c5f4fe92379f0dcf0fe6ae257d91f06} } |
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Masson, P. and Halkyard, C. | Structural intensity in dual-mode propagation for damage characterization. | 2009 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 7295 |
conference | DOI URL |
Abstract: In complex structures such as lap joints, extracting the information associated with damage from the measured signal can be challenging. An approach is presented, based on the use of high frequency bursts injected into a structure using an actuator and the measurement of structural intensity using a compact array of sensors, located remotely from the damage. The approach implements structural intensity estimation using the Timoshenko beam formulation, including dual-mode propagation above the cut-off frequency of the A1 Lamb mode. The structural intensity is first expressed within Timoshenko beam theory and the use of the wave decomposition approach is proposed to allow its measurement. Simulations are then conducted to illustrate localized time-domain structural intensity measurement for a burst propagating in a semi-infinite beam with a notch represented by a thickness variation. Results show that below the cut-off frequency, the burst propagates as a shear-dominated wave (mode A0) while a moment-dominated burst also propagates above the cut-off frequency (mode A1). Experimental results show that both shear and moment components of intensity can be measured for frequencies below and above the cut-off frequency and that the notch can be detected. Structural intensity measurement is then applied to the detection of a notch in a simulated lap joint region of a beam. The results demonstrate the potential benefit of using the structural intensity to extract useful information from the dual-mode interference for characterizing the location and depth of the notch. © 2009 SPIE. | |||||
BibTeX:
@conference{Masson2009, author = {Masson, P. and Halkyard, C.R.}, title = {Structural intensity in dual-mode propagation for damage characterization.}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2009}, volume = {7295}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-66749084011&doi=10.1117%2f12.811937&partnerID=40&md5=4b37a80e888beeb60c8e95f40162206d}, doi = {https://doi.org/10.1117/12.811937} } |
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Masson, P. and Micheau, P. | Compact piezoelectric arrays for imaging strategies in damage detection | 2009 | Structural Health Monitoring 2009: From System Integration to Autonomous Systems - Proceedings of the 7th International Workshop on Structural Health Monitoring, IWSHM 2009 Vol. 2, pp. 1256-1263 |
conference | URL |
Abstract: In this paper, the performance of a compact piezoelectric array is assessed for damage detection in a simple test case by implementing several array processing techniques. The test coupon consists of an aluminium plate with a notched hole, and is instrumented with two sensing arrays. Each linear array of seven sensing elements is fabricated in a bulk piezoceramic (PZT) using laser micro-machining. The first imaging technique to be implemented to process the signals measured by the elements of the array is related to the Embedded Ultrasonic Structural Radar (EUSR). The second technique implements the Multiple Signal Classification (MUSIC) algorithm which has the potential to discriminate between sources in the inspected area. This algorithm can be implemented either to obtain the pseudo-spectrum in the wavenumber domain for directive scanning, or in the time domain using a synthetic approach. The third technique exploits a synthetic time reversal approach based on the Time Domain Topological Gradient (TDTG) algorithm. Imaging results are presented for each technique with AO and SO modes propagating in the coupon at different frequencies. Although the results reveal that a 2 mm long notch can be detected using these imaging techniques, the TDTG algorithm seems the most promising for discrimination between the echoes from the notch and the hole. | |||||
BibTeX:
@conference{Masson20091256, author = {Masson, P. and Micheau, P.}, title = {Compact piezoelectric arrays for imaging strategies in damage detection}, journal = {Structural Health Monitoring 2009: From System Integration to Autonomous Systems - Proceedings of the 7th International Workshop on Structural Health Monitoring, IWSHM 2009}, year = {2009}, volume = {2}, pages = {1256-1263}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953494188&partnerID=40&md5=b0334d0d51526ab7a7a335414babda24} } |
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Panneton, R. | Sound transmission loss evaluation of trim panel samples by surface impedance measurements | 2009 | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 Vol. 2, pp. 1050-1056 |
conference | URL |
Abstract: This paper presents some experimental validations of a recently developed method to deduce the normal incidence sound transmission loss (nSTL) of an acoustical element from upstream surface impedance (USI) measurements in a classical two-microphone impedance tube. From three surface impedance measurements, an equivalent transfer matrix is found and the nSTL deduced. From this equivalent transfer matrix, an attempt is made to estimate the diffuse field sound transmission loss (dSTL) from normal incidence measurements. The nSTL and dSTL measured with the USI method are compared to the classical four-microphone/two-load method and to diffused field measurements, respectively. In general, good correlations are obtained. However, some problems are identified and discussed. | |||||
BibTeX:
@conference{Panneton20091050, author = {Panneton, R.}, title = {Sound transmission loss evaluation of trim panel samples by surface impedance measurements}, journal = {38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009}, year = {2009}, volume = {2}, pages = {1050-1056}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870013763&partnerID=40&md5=e745d858cf0ebb501d971f6a7cc71023} } |
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Panneton, R. | Normal incidence sound transmission loss evaluation by upstream surface impedance measurements | 2009 | Journal of the Acoustical Society of America Vol. 125(3), pp. 1490-1497 |
article | DOI URL |
Abstract: A method is developed to obtain the normal incidence sound transmission loss of noise control elements used in piping systems from upstream surface impedance measurements only. The noise control element may be a small material specimen in an impedance tube, a sealing part in an automotive hollow body network, an expansion chamber, a resonator, or a muffler. The developments are based on a transfer matrix (four-pole) representation of the noise control element and on the assumption that only plane waves propagate upstream and downstream the element. No assumptions are made on its boundary conditions, dimensions, shape, and material properties (i.e., the element may be symmetrical or not along its thickness, homogeneous or not, isotropic or not). One-load and two-load procedures are also proposed to identify the transfer matrix coefficients needed to obtain the true transmission loss of the tested element. The method can be used with a classical two-microphone impedance tube setup (i.e., no additional downstream tube and downstream acoustical measurements). The method is tested on three different noise control elements: two impedance tube multilayered specimens and one expansion chamber. The results found using the developed method are validated using numerical simulations. © 2009 Acoustical Society of America. | |||||
BibTeX:
@article{Panneton20091490, author = {Panneton, R.}, title = {Normal incidence sound transmission loss evaluation by upstream surface impedance measurements}, journal = {Journal of the Acoustical Society of America}, year = {2009}, volume = {125}, number = {3}, pages = {1490-1497}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-62249163654&doi=10.1121%2f1.3076929&partnerID=40&md5=02714cb57d432ce3c159c2bf78ba5bf6}, doi = {https://doi.org/10.1121/1.3076929} } |
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Quaegebeur, N., Micheau, P. and Berry, A. | Decentralized harmonic control of sound radiation and transmission by a plate using a virtual impedance approach | 2009 | Journal of the Acoustical Society of America Vol. 125(5), pp. 2978-2986 |
article | DOI URL |
Abstract: The problem under study in this article is the active control of sound transmission and radiation of a panel under a periodic excitation. The control strategy investigated uses independent control loops between an individual polyvinylidene fluoride (PVDF) sensor and an individual lead zirconate titanate (PZT) actuator. The specific approach employed here uses the concept of virtual impedance. The aim is to determine for each frequency the optimal impedance between each PVDF sensor and the corresponding PZT actuator in order to reduce the sound power radiated by the plate. Theoretical predictions are compared to measurements of the sound radiated and transmission loss of a panel mounted with eight PZT-PVDF units. Reductions of up to 20 dB of the acoustic power can be achieved around mechanical resonances of the system, while the control strategy has little effect for off-resonance excitations. © 2009 Acoustical Society of America. | |||||
BibTeX:
@article{Quaegebeur20092978, author = {Quaegebeur, N. and Micheau, P. and Berry, A.}, title = {Decentralized harmonic control of sound radiation and transmission by a plate using a virtual impedance approach}, journal = {Journal of the Acoustical Society of America}, year = {2009}, volume = {125}, number = {5}, pages = {2978-2986}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-65549119717&doi=10.1121%2f1.3106124&partnerID=40&md5=ff53ec863f28cab590e58a267e1e93c0}, doi = {https://doi.org/10.1121/1.3106124} } |
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Rakic, A., Amédin, C., Atalla, N. and Panneton, R. | Comparison between experimental measurements of the flow resistance at high speed and the theoretical models | 2009 | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 Vol. 2, pp. 1037-1043 |
conference | URL |
Abstract: Liners are generally used for the design of aircraft nacelles in order to reduce noise. A typical liner consists of a honeycomb core sandwiched between a perforated plate and a rigid plate. The thickness of the core and the flow resistance of the perforated plate are the main parameters controlling the acoustic response of the liner. The measurement of the flow resistance of the perforated plate is usually performed using a high speed flow rig. Such a rig was constructed and compared to theoretical models. An alternative method is investigated to predict a flow resistance of perforated plates. It is an acoustical method and some results are shown in this paper. More investigation is necessary to conclude on validity of this method. | |||||
BibTeX:
@conference{Rakic20091037, author = {Rakic, A. and Amédin, C.K. and Atalla, N. and Panneton, R.}, title = {Comparison between experimental measurements of the flow resistance at high speed and the theoretical models}, journal = {38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009}, year = {2009}, volume = {2}, pages = {1037-1043}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870013542&partnerID=40&md5=28e34b99329c69f4e9287b2d03191ed7} } |
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Ren, Z., Atalla, N. and Ghinet, S. | Identification of dynamic properties of linearly viscoelastic materials using Vibrating Beam Technique and optimization | 2009 | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 Vol. 2, pp. 1116-1124 |
conference | URL |
Abstract: Sandwich structures with viscoelastic material core and metal faces can be used to greatly reduce the vibration in automobile industry. Several experimental methods such as Dynamical Mechanical Analysis (DMA) and Vibrating Beam Technique (VBT) are available to characterize the dynamic properties of viscoelastic materials as a function of frequency and tmperature. In an attempt to better control the effect of boundary conditions in the clamped-free VBT, especially for the laminated steel, and to automate the creation of the nomogram, this paper investigates the use of a free-free beam setup in combination with an optimisation method to derive the core properties of viscoelastic materials. Based on measured input mobilities, a frequency response function based optimization method is proposed to identify the dynamic properties. In the method, the normal mode superposition method, considering the added mass effect, is used as a solver for the optimization. The sandwich model is based on RKU equations and the fourparameter fractional derivative model is used in conjunction with WLF equation to describe the frequency temperature dependent behaviour of the viscoelastic material. The nomogram is a direct result of the optimization process. Several applications are described to assess the performance of this method. In particular, a systematic comparison with both the VBT and DMA is presented. | |||||
BibTeX:
@conference{Ren20091116, author = {Ren, Z. and Atalla, N. and Ghinet, S.}, title = {Identification of dynamic properties of linearly viscoelastic materials using Vibrating Beam Technique and optimization}, journal = {38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009}, year = {2009}, volume = {2}, pages = {1116-1124}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869995032&partnerID=40&md5=eaac71996e2a91f28253fe11f076b6e7} } |
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Robert, R., Micheau, P., Beaulieu, A., Avoine, O. and Walti, H. | Two distinct controllers for pressure regulation in total liquid ventilation | 2009 | IFAC Proceedings Volumes (IFAC-PapersOnline) Vol. 7(PART 1), pp. 234-239 |
conference | DOI URL |
Abstract: Total liquid ventilation is an experimental method of mechanical assisted ventilation in which lungs are totally filled and then ventilated with a tidal volume of perfluorochemical liquid by using a liquid ventilator. However to apply this approach to humans, liquid ventilators must reach the same level of reliability as conventional mechanical gas ventilators. In control terms, the problem is to design a controller to perform pressure regulated ventilation in spite of large uncertainties on physiological parameters, and nonlinear behavior of the lungs. The presented pressure controlled ventilation mode is similar to those used in conventional gas ventilator excepted that the airway pressure and the positive end-expiratory pressure require two distinct controllers. Simulations, in-vitro experiments and in-vivo results with 5 healthy term newborn lambs have validated the presented controllers. © 2009 IFAC. | |||||
BibTeX:
@conference{Robert2009234, author = {Robert, R. and Micheau, P. and Beaulieu, A. and Avoine, O. and Walti, H.}, title = {Two distinct controllers for pressure regulation in total liquid ventilation}, journal = {IFAC Proceedings Volumes (IFAC-PapersOnline)}, year = {2009}, volume = {7}, number = {PART 1}, pages = {234-239}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051598515&doi=10.3182%2f20090812-3-DK-2006.0078&partnerID=40&md5=7f53ffdb8b1b93f202f842a9d89934ee}, doi = {https://doi.org/10.3182/20090812-3-DK-2006.0078} } |
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Robert, R., Micheau, P. and Walti, H. | Optimal expiratory volume profile in tidal liquid ventilation under steady state conditions, based on a symmetrical lung model | 2009 | ASAIO Journal Vol. 55(1), pp. 63-72 |
article | DOI URL |
Abstract: Liquid-assisted ventilation (LAV) using perfluorochemicals (PFC) offers clear theoretical advantages over gas ventilation. During tidal liquid ventilation (TLV) the residual capacity of the lungs is filled with PFC and a liquid ventilator is necessary to inhale and exhale the tidal volume of PFC. However, during the expiration phase, a flow limitation (choked flow) can be observed, which compromises minute ventilation and consequently the gas exchange. The hypothesis of the presented works is that the choked flow can be avoided by profiling the expiratory volume. To validate this concept, an elastic symmetrical lung numerical model, used to characterize forced expiration in gas ventilation, was transposed to TLV. The parameters of the developed numerical model were fitted from experimental data obtained on a newborn lamb. The results obtained demonstrate that general observations made with gas ventilation still hold, however, in TLV: flow limitation in the central airways is the result of a coupling between viscous pressure losses and airway compliance, and the flow limiting segment is located in the central airways. Using the model results, an optimal theoretical expiratory profile seems to be exponential as first approximation, and its time constant is dependent on the chocked flow mechanism and not on the product of resistance by compliance. This optimal profile is used to compute the maximal minute ventilation allowable with an acceptable risk of collapse. Also, the sensitivity of minute ventilation to different parameter variations were analyzed and practical recommendations are proposed. © 2009 Amercian Society of Artificial Internal Organs. | |||||
BibTeX:
@article{Robert200963, author = {Robert, R. and Micheau, P. and Walti, H.}, title = {Optimal expiratory volume profile in tidal liquid ventilation under steady state conditions, based on a symmetrical lung model}, journal = {ASAIO Journal}, year = {2009}, volume = {55}, number = {1}, pages = {63-72}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-62449293208&doi=10.1097%2fMAT.0b013e3181911821&partnerID=40&md5=284e5cad80c847883465d304d930434b}, doi = {https://doi.org/10.1097/MAT.0b013e3181911821} } |
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Roy, R., Micheau, P. and Bourassa, P. | Intermittent predictive steering control as an automobile driver model | 2009 | Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME Vol. 131(1), pp. 1-6 |
article | DOI URL |
Abstract: The originality of this paper is the evaluation of intermittent control as a viable candidate to represent an automobile driver in a path tracking scenario. The control algorithm is based on general predictive control where the road curvature is considered known for a horizon in front of the automobile. The computed steering wheel command is used in an intermittent fashion, the intermittence period being one of the system parameter to study. Simulations are carried out and parameters of the driver, the automobile, and the road are varied. An intermittence period range giving satisfactory performances is observed. A comparison is made with actual car/driver behavior measurements for a lane change maneuver. It is concluded that, according to this driver model, there is a wide range of intermittence period that the automobile driver may be operating. Moreover, it is suggested to consider the intermittency of information as an important parameter for vehicle safety systems. Copyright © 2009 by ASME. | |||||
BibTeX:
@article{Roy20091, author = {Roy, R. and Micheau, P. and Bourassa, P.}, title = {Intermittent predictive steering control as an automobile driver model}, journal = {Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME}, year = {2009}, volume = {131}, number = {1}, pages = {1-6}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955904964&doi=10.1115%2f1.3023127&partnerID=40&md5=4eb6fb2cb0f4c6ea6e1844d09e314c91}, doi = {https://doi.org/10.1115/1.3023127} } |
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Salissou, Y. and Panneton, R. | A general wave decomposition formula for the measurement of normal incidence sound transmission loss in impedance tube | 2009 | Journal of the Acoustical Society of America Vol. 125(4), pp. 2083-2090 |
article | DOI URL |
Abstract: Two types of general methods can be found in the literature for the determination of the normal incidence sound transmission loss (nSTL) of acoustical elements. The first one is based on the transfer matrix (TM) approach, and the second one is based on the wavefield decomposition (WD) theory. From all the techniques proposed in the literature, the general TM methods (two-load or two-source location) are the only methods yielding the exact nSTL of an acoustical element without any assumptions on its symmetry and on the termination (i.e., the load). Except for the case of an anechoic termination, there is no method based on the WD theory which yields exact nSTL. This paper presents a general WD method to measure the exact nSTL of an acoustical element without any assumptions on its symmetry and on the termination. Similar to general TM methods for non-symmetrical elements, four microphones and two loads will be required. As a first validation of the method, symmetrical and non-symmetrical porous materials are investigated. Results are discussed and compared with some existing methods and with the classical two-load method. A perfect agreement is found with the classical two-load method. © 2009 Acoustical Society of America. | |||||
BibTeX:
@article{Salissou20092083, author = {Salissou, Y. and Panneton, R.}, title = {A general wave decomposition formula for the measurement of normal incidence sound transmission loss in impedance tube}, journal = {Journal of the Acoustical Society of America}, year = {2009}, volume = {125}, number = {4}, pages = {2083-2090}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-64649093827&doi=10.1121%2f1.3081504&partnerID=40&md5=e426caa88c731befce7b64e0ef7c3d20}, doi = {https://doi.org/10.1121/1.3081504} } |
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Sgard, F., Nélisse, H., Atalla, N., Amedin, C. and Oddo, R. | Prediction of the insertion loss of large enclosures using a combined SEA/image sources approach | 2009 | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 Vol. 4, pp. 2835-2843 |
conference | URL |
Abstract: Large enclosures are a well-known solution to reduce the sound exposure of workers to the noise radiated by machinery. However no simple and fast tool is available to predict reliably their acoustical performance taking into account their complexity. Given the large size of studied enclosures and uncertainties related to the properties of panels and their mounting conditions, a statistical energy analysis (SEA) approach is relevant. This paper presents a hybrid model for the prediction of the acoustic performance of enclosures over a large frequency range. It combines SEA for the sound transmission across the various elements of the enclosure and the image sources method for better describing the sound field inside the enclosure. More precisely, the internal space is substructured into subcavities and the image sources technique is used to calculate sound pressure levels at several points inside each subcavity. These levels are then spatially averaged and assigned to each sub-cavity which amounts to imposing the sound energy in each acoustical SEA subsystem. This paper investigates the effect of the substructuring scheme of the internal space on the predicted insertion loss of rectangular and L-shape enclosures surrounding a point source using experimental data as a reference. | |||||
BibTeX:
@conference{Sgard20092835, author = {Sgard, F.C. and Nélisse, H. and Atalla, N. and Amedin, C.K. and Oddo, R.}, title = {Prediction of the insertion loss of large enclosures using a combined SEA/image sources approach}, journal = {38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009}, year = {2009}, volume = {4}, pages = {2835-2843}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870013185&partnerID=40&md5=dd5c25313ba015784cacef8e27bd10d7} } |
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Ahmed, M., Atalla, N. and Park, C. | Assessment of the potentiality of microcellular plastic foams for passive noise control in automotive structures | 2008 | Technical Papers, Regional Technical Conference - Society of Plastics Engineers Vol. 2, pp. 1109-1112 |
conference | URL |
Abstract: Microcellular foams have a unique structure and morphology as compared to conventional acoustical foams. The structure is highly dense (in the range of 10E9 to 10E12 cells/cm3) and highly random. The objective of this study is to assess the potentiality of this new acoustical material for passive noise control in automotive structures. In this context, statistical and fundamental studies of the sound absorption behaviors of microcellular foams are performed. The study concluded that a localized behavior is in effect due to the unique microstructure, and therefore, it should be taken into account while modeling this class of materials. Finally some design recommendations are provided based on the newly developed model along with the understanding of the effects of morphology on the absorption behavior. | |||||
BibTeX:
@conference{Ahmed20081109, author = {Ahmed, M.Y.S. and Atalla, N. and Park, C.B.}, title = {Assessment of the potentiality of microcellular plastic foams for passive noise control in automotive structures}, journal = {Technical Papers, Regional Technical Conference - Society of Plastics Engineers}, year = {2008}, volume = {2}, pages = {1109-1112}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-52349083471&partnerID=40&md5=5a43289eaceea808530d9491f82b37a5} } |
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Ahmed, M., Wang, C., Atalla, N. and Park, C. | Investigation of the acoustical behaviors of microcellular ceramic foams | 2008 | Technical Papers, Regional Technical Conference - Society of Plastics Engineers Vol. 2, pp. 1287-1291 |
conference | URL |
Abstract: The processing method for fabricating high porosity microcellular ceramic foams for sound absorption applications is discussed. By controlling the microsphere content and that of the base elastomer, it was possible to adjust the porosity with a very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9E8 - 1.6E9 cells/cm3) and desired expansion ratios (3-6 folds). Sound absorption testing was performed by using standard test methods, followed by a statistical and theoretical study that was performed to investigate the acoustical behavior of this class of materials. The study shows that due the unique structure of these foams, localized effects took place and therefore, application of the new morphology-based model was necessary to account for the effects of microstructure and morphology on the sound absorption behaviors of ceramic foams. | |||||
BibTeX:
@conference{Ahmed20081287, author = {Ahmed, M.Y.S. and Wang, C. and Atalla, N. and Park, C.B.}, title = {Investigation of the acoustical behaviors of microcellular ceramic foams}, journal = {Technical Papers, Regional Technical Conference - Society of Plastics Engineers}, year = {2008}, volume = {2}, pages = {1287-1291}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-52349121231&partnerID=40&md5=9fa5e13a893be94f3ef717b1b8d8bc8f} } |
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Amichi, K., Atalla, N. and Ruokolainen, R. | An efficient sandwich plate element for predicting the vibroacoustic response of laminated steel panels | 2008 | American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCAD, pp. 389-396 | conference | DOI URL |
Abstract: A New finite element sandwich plate is presented. It is based on discrete displacement approach and allows for both symmetrical and unsymmetrical configurations. The validity and accuracy of the presented element is assessed through comparisons with both tests and classical FE modeling. The tests consist of various configurations of sandwich panels in a coupled plate-cavity system. A parametric study, using the developed element, is finally presented to highlights the effects of skin and core properties on the vibration and radiation of such structures under both airborne and structure-borne excitations. Copyright © 2008 by ASME. | |||||
BibTeX:
@conference{Amichi2008389, author = {Amichi, K. and Atalla, N. and Ruokolainen, R.}, title = {An efficient sandwich plate element for predicting the vibroacoustic response of laminated steel panels}, journal = {American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCAD}, year = {2008}, pages = {389-396}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80053125510&doi=10.1115%2fNCAD2008-73080&partnerID=40&md5=d1fa4fb41d19b876f981256b175177f2}, doi = {https://doi.org/10.1115/NCAD2008-73080} } |
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Bédard, M. and Berry, A. | Development of a directivity-controlled piezoelectric transducer for sound reproduction | 2008 | Journal of Sound and Vibration Vol. 311(3-5), pp. 1271-1285 |
article | DOI URL |
Abstract: Present sound reproduction systems do not attempt to simulate the spatial radiation of musical instruments, or sound sources in general, even though the spatial directivity has a strong impact on the psychoacoustic experience. A transducer consisting of 4 piezoelectric elemental sources made from curved PVDF films is used to generate a target directivity pattern in the horizontal plane, in the frequency range of 5 - 20 kHz. The vibratory and acoustical response of an elemental source is addressed, both theoretically and experimentally. Two approaches to synthesize the input signals to apply to each elemental source are developed in order to create a prescribed, frequency-dependent acoustic directivity. The circumferential Fourier decomposition of the target directivity provides a compromise between the magnitude and the phase reconstruction, whereas the minimization of a quadratic error criterion provides a best magnitude reconstruction. This transducer can improve sound reproduction by introducing the spatial radiation aspect of the original source at high frequency. © 2007 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Bédard20081271, author = {Bédard, M. and Berry, A.}, title = {Development of a directivity-controlled piezoelectric transducer for sound reproduction}, journal = {Journal of Sound and Vibration}, year = {2008}, volume = {311}, number = {3-5}, pages = {1271-1285}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-38749092050&doi=10.1016%2fj.jsv.2007.10.016&partnerID=40&md5=9d09d67bbcde32bf51da2d323617655c}, doi = {https://doi.org/10.1016/j.jsv.2007.10.016} } |
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Chevillotte, F., Panneton, R., Bougrab, H., Chaut, C. and Wojtowicki, J.-L. | Coupling transfer matrix method to finite element method for the analysis of hollow body networks with passive or reactive elements | 2008 | Proceedings - European Conference on Noise Control, pp. 6351-6354 | conference | URL |
Abstract: This work shows how to couple transfer matrix method to finite element method with a view to analyze the acoustic response of an automotive hollow body network with a minimum of memory requirements and computational time. A hollow body network is made up from a series of elongated fluid partitions similar to waveguides. These fluid partitions are generally separated by sealing parts. In the proposed hybrid model, the elongated fluid partitions are modeled using one-dimensional fluid finite elements, and the sealing parts using transfer matrices. After discretization of the acoustic pressure and application of the variational principle, the global finite element matrix system is obtained, where only the nodal pressures in the fluid partitions remain. During this process, each transfer matrix has been converted into a kind of admittance matrix, where no additional degrees of freedom are necessary to take into account the sealing parts into the finite element model. The so called TM-FEM method is applied on a simple hollow body network and compared to experimental measurements. Good correlations are obtained. | |||||
BibTeX:
@conference{Chevillotte20086351, author = {Chevillotte, F. and Panneton, R. and Bougrab, H. and Chaut, C. and Wojtowicki, J.-L.}, title = {Coupling transfer matrix method to finite element method for the analysis of hollow body networks with passive or reactive elements}, journal = {Proceedings - European Conference on Noise Control}, year = {2008}, pages = {6351-6354}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874841435&partnerID=40&md5=d9fde5a88d5cc4a4512116375a60ddb2} } |
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Chu, R., Naguib, H. and Atalla, N. | Synthesis and characterization of open-cell foams for sound absorption with rotational molding method | 2008 | Technical Papers, Regional Technical Conference - Society of Plastics Engineers Vol. 2, pp. 1029-1033 |
conference | URL |
Abstract: Open-cell foams have better sound absorption abilities over conventional closed-cell foams. One approach to develop new foamed materials with improved acoustic abilities is to control their cellular-structural properties through the manipulation of processing parameters. This paper presents a novel method to process open-cell polymeric foams. A combined process of rotational foam molding and particulate leaching was used to produce open-cell foams for acoustic absorption. Foamed samples were characterized on their cellular morphologies and acoustic properties. | |||||
BibTeX:
@conference{Chu20081029, author = {Chu, R.K.M. and Naguib, H.E. and Atalla, N.}, title = {Synthesis and characterization of open-cell foams for sound absorption with rotational molding method}, journal = {Technical Papers, Regional Technical Conference - Society of Plastics Engineers}, year = {2008}, volume = {2}, pages = {1029-1033}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-52349102386&partnerID=40&md5=8d1bdfcba540c63cf6122d773849b689} } |
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Couillard, M., Micheau, P. and Masson, P. | Improved clipped periodic optimal control for semi-active harmonic disturbance rejection | 2008 | Journal of Sound and Vibration Vol. 318(4-5), pp. 737-756 |
article | DOI URL |
Abstract: This paper presents a new approach for harmonic disturbance rejection using semi-active vibration control. The approach is illustrated through application to the problem of maximizing the energy dissipated by a semi-active damper under harmonic excitation. In order to establish a baseline for the evaluation of the performance of the semi-active damper, the effectiveness of the optimal passive and active cases are first presented. The study then examines the ability of the clipped optimal control (or clipping control) approach to improve the energy dissipation capacity of the semi-active damper over the optimal passive damper. An approximate solution to the nonlinear dynamic problem, obtained using the method of averaging, and a time integration based numerical method indicate that this approach improves the energy dissipated by the semi-active damper over the optimal passive damper. The approach presented in this paper intends to further "improve", or "fine tune", the control parameters given by the clipped optimal control approach. This is done using an approximated solution of the problem and an appropriate optimization algorithm. Results clearly indicate that this new approach provides significant improvement on energy dissipation over the clipped optimal control approach for the semi-active damper. © 2008 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Couillard2008737, author = {Couillard, M. and Micheau, P. and Masson, P.}, title = {Improved clipped periodic optimal control for semi-active harmonic disturbance rejection}, journal = {Journal of Sound and Vibration}, year = {2008}, volume = {318}, number = {4-5}, pages = {737-756}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-55349125346&doi=10.1016%2fj.jsv.2008.04.034&partnerID=40&md5=c4421565988b0dcaf56b202b58725ca9}, doi = {https://doi.org/10.1016/j.jsv.2008.04.034} } |
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Dazel, O., Sgard, F., Becot, F.-X. and Atalla, N. | Expressions of dissipated powers and stored energies in poroelastic media modeled by u,U and u,P formulations | 2008 | Journal of the Acoustical Society of America Vol. 123(4), pp. 2054-2063 |
article | DOI URL |
Abstract: This paper is devoted to the rigorous obtention of the energy balance in porous materials. The wave propagation in the porous media is described by Biot-Allard's u,U and u,P formulations. The paper derives the expressions for stored kinetic and strain energies together with dissipated energies. It is shown that, in the case of mixed formulations, these expressions do not correspond to the real and imaginary parts of the variational formulations. A quantitative convergence analysis of finite element scheme is then undertaken with the help of these indicators. It is shown that the order of convergence of these indicators for linear finite-element is one and that they are then well fitted to check the validity of finite-element models. © 2008 Acoustical Society of America. | |||||
BibTeX:
@article{Dazel20082054, author = {Dazel, O. and Sgard, F. and Becot, F.-X. and Atalla, N.}, title = {Expressions of dissipated powers and stored energies in poroelastic media modeled by u,U and u,P formulations}, journal = {Journal of the Acoustical Society of America}, year = {2008}, volume = {123}, number = {4}, pages = {2054-2063}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-41849085902&doi=10.1121%2f1.2874520&partnerID=40&md5=f292d6fd3f3645109017c2143380d01c}, doi = {https://doi.org/10.1121/1.2874520} } |
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Duvareille, C., Samson, N., St-Hilaire, M., Micheau, P., Bournival, V. and Praud, J.-P. | Effects of hypercapnia on non-nutritive swallowing in newborn lambs | 2008 | Advances in Experimental Medicine and Biology Vol. 605, pp. 413-417 |
article | DOI URL |
Abstract: The purpose of this study was to determine the effect of hypercapnia on non-nutritive swallowing (NNS) frequency and on NNS-breathing coordination in newborn lambs. Six lambs were chronically instrumented for recording electroencephalogram, eye movements, diaphragm and thyroarytenoid muscle activity, nasal airflow and electrocardiogram. Each lamb was placed in a Plexiglas chamber and exposed to a hypercapnic gas mixture (21% O2, 5% CO2). Polysomnographic recordings were conducted in non-sedated lambs using a custom-designed radiotelemetry system. Results show that hypercapnia increased NNS frequency in all three states of alertness (p < 0.0001 to 0.03), through a specific increase in ie-type NNS. Causal mechanisms and potential consequences of such observations on aspirations and apneas, as well as on swallowing maturation, will require further studies. © 2008 Springer Science+Business Media, LLC. | |||||
BibTeX:
@article{Duvareille2008413, author = {Duvareille, C. and Samson, N. and St-Hilaire, M. and Micheau, P. and Bournival, V. and Praud, J.-P.}, title = {Effects of hypercapnia on non-nutritive swallowing in newborn lambs}, journal = {Advances in Experimental Medicine and Biology}, year = {2008}, volume = {605}, pages = {413-417}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-38449111832&doi=10.1007%2f978-0-387-73693-8_72&partnerID=40&md5=9c6e67faf440def4e1be7521872adb46}, doi = {https://doi.org/10.1007/978-0-387-73693-8_72} } |
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Francoeur, D. and Berry, A. | Time reversal of flexural waves in a beam at audible frequency | 2008 | Journal of the Acoustical Society of America Vol. 124(2), pp. 1006-1017 |
article | DOI URL |
Abstract: There has been very limited work on the application of time Reversal to the propagation of audible frequency waves in mechanical structures. The present work concentrates on the application of time reversal to the focusing of audible range, flexural waves in an infinite beam, and to the detection of local heterogeneity in such a beam. Practical applications of time reversal of flexural waves in structures include vibration energy focusing, detection of vibratory or acoustic sources, and detection of defects in mechanical structures. An analytical model of flexural wave propagation in the beam as well as sensing and emission using piezoelectric transducers is presented. Time reversal experiments are conducted and compared to the model results in either a homogeneous beam or a beam with point mass heterogeneities. In the various situations tested, it is shown that time reversal effectively compensates the spreading in time of the impulse due to the dispersive propagation of flexural waves. One interesting aspect of this property is the generation of large amplitude impulsive responses in the beam using remote actuators. Finally, the "Décomposition de l'Opérateur de Retournement Temporel" approach is examined to detect and localize point mass scatterers in the beam. © 2008 Acoustical Society of America. | |||||
BibTeX:
@article{Francoeur20081006, author = {Francoeur, D. and Berry, A.}, title = {Time reversal of flexural waves in a beam at audible frequency}, journal = {Journal of the Acoustical Society of America}, year = {2008}, volume = {124}, number = {2}, pages = {1006-1017}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-49249085786&doi=10.1121%2f1.2945160&partnerID=40&md5=f7e618b73ae649252690ade57dbb522d}, doi = {https://doi.org/10.1121/1.2945160} } |
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Gauthier, P.-A. and Berry, A. | Adaptive wave field synthesis for active sound field reproduction: Experimental results | 2008 | Journal of the Acoustical Society of America Vol. 123(4), pp. 1991-2002 |
article | DOI URL |
Abstract: Sound field reproduction has applications in music reproduction, spatial audio, sound environment reproduction, and experimental acoustics. Sound field reproduction can be used to artificially reproduce the spatial character of natural hearing. The objective is then to reproduce a sound field in a real reproduction environment. Wave field synthesis (WFS) is a known open-loop technology which assumes that the reproduction environment is anechoic. The room response thus reduces the quality of the physical sound field reproduction by WFS. In recent research papers, adaptive wave field synthesis (AWFS) was defined as a potential solution to compensate for these quality reductions from which WFS objective performance suffers. In this paper, AWFS is experimentally investigated as an active sound field reproduction system with a limited number of reproduction error sensors to compensate for the response of the listening environment. Two digital signal processing algorithms for AWFS are used for comparison purposes, one of which is based on independent radiation mode control. AWFS performed propagating sound field reproduction better than WFS in three tested reproduction spaces (hemianechoic chamber, standard laboratory space, and reverberation chamber). © 2008 Acoustical Society of America. | |||||
BibTeX:
@article{Gauthier20081991, author = {Gauthier, P.-A. and Berry, A.}, title = {Adaptive wave field synthesis for active sound field reproduction: Experimental results}, journal = {Journal of the Acoustical Society of America}, year = {2008}, volume = {123}, number = {4}, pages = {1991-2002}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-41849129905&doi=10.1121%2f1.2875844&partnerID=40&md5=15426be1b7b33ca358470b493f16791b}, doi = {https://doi.org/10.1121/1.2875844} } |
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Gauthier, P.-A. and Berry, A. | Adaptive wave field synthesis for broadband active sound field reproduction: Signal processing | 2008 | Journal of the Acoustical Society of America Vol. 123(4), pp. 2003-2016 |
article | DOI URL |
Abstract: Sound field reproduction is a physical approach to the reproduction of the natural spatial character of hearing. It is also useful in experimental acoustics and psychoacoustics. Wave field synthesis (WFS) is a known open-loop technology which assumes that the reproduction environment is anechoic. A real reflective reproduction space thus reduces the objective accuracy of WFS. Recently, adaptive wave field synthesis (AWFS) was defined as a combination of WFS and active compensation. AWFS is based on the minimization of reproduction errors and on the penalization of departure from the WFS solution. This paper focuses on signal processing for AWFS. A classical adaptive algorithm is modified for AWFS: filtered-reference least-mean-square. This modified algorithm and the classical equivalent leaky algorithm have similar convergence properties except that the WFS solution influences the adaptation rule of the modified algorithm. The paper also introduces signal processing for independent radiation mode control of AWFS on the basis of plant decoupling. Simulation results for AWFS are introduced for free-field and reflective spaces. The two algorithms effectively reproduce the sound field and compensate for the reproduction errors at the error sensors. The independent radiation mode control allows a more flexible tuning of the algorithm. © 2008 Acoustical Society of America. | |||||
BibTeX:
@article{Gauthier20082003, author = {Gauthier, P.-A. and Berry, A.}, title = {Adaptive wave field synthesis for broadband active sound field reproduction: Signal processing}, journal = {Journal of the Acoustical Society of America}, year = {2008}, volume = {123}, number = {4}, pages = {2003-2016}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-41849116671&doi=10.1121%2f1.2875269&partnerID=40&md5=24483ff5de87219f1b1a379ee69146cd}, doi = {https://doi.org/10.1121/1.2875269} } |
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Gauthier, J.-P. and Micheau, P. | Extremal harmonic active control of power for rotating machines | 2008 | Journal of Sound and Vibration Vol. 318(4-5), pp. 663-677 |
article | DOI URL |
Abstract: Most of the time, the speed of rotating machines oscillates in synchronization with the rotor position. Those speed fluctuations, generated by disturbance torques, can be actively controlled with a second torque source coupled to the shaft of the machine. To achieve this active control, the problem is reformulated in the harmonic domain with regard to the main order of the fluctuations. The control objective is to extremalize an energetic criterion like kinetic energy (cancelling the speed ripple), reactive power (to add a virtual flywheel) or active power (to charge a battery). To reach those objectives, two extremal controllers are proposed with implicit or explicit criterion management. The controllers are tested on an academic test bed. The results show that the controllers converge at the extremum of each criterion. © 2008 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Gauthier2008663, author = {Gauthier, J.-P. and Micheau, P.}, title = {Extremal harmonic active control of power for rotating machines}, journal = {Journal of Sound and Vibration}, year = {2008}, volume = {318}, number = {4-5}, pages = {663-677}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-55349141107&doi=10.1016%2fj.jsv.2008.04.049&partnerID=40&md5=ca648c2db5677ecf5f34b2cf01a3a548}, doi = {https://doi.org/10.1016/j.jsv.2008.04.049} } |
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Ghinet, S. and Atalla, N. | Noise transmission loss of orthotropic sandwich composite panels | 2008 | Institute of Noise Control Engineering of the USA - 23rd National Conference on Noise Control Engineering, NOISE-CON 08 and Sound Quality Symposium, SQS 08 Vol. 2, pp. 574-582 |
conference | URL |
Abstract: The majority of published vibroacoustic models for sandwich composite panels assume mainly antisymmetric motion in which the core is considered to principally support shearing deformations without any compression deformation over the thickness. Such modeling is appropriate for panels with relatively stiff and thin core but symmetric motion becomes important when the core is thick and soft. Under symmetric motion conditions the compression deformations over the core's thickness become significant. The paper deals with the modeling of diffuse field transmission of symmetrical sandwich panels with thin composite skins and soft compressible core. The layers of the panel are assumed orthotropic. Both symmetric and antisymmetric modes of propagation are accounted for analytically and their impact on the transmission loss is presented. It is shown that the noise transmission loss is largely affected by the orthotropy of the layers as well as the symmetric propagating behaviors. Experimental and literature results are compared with numerical simulations using the present theoretical approach to demonstrate its validity and effectiveness. Copyright © 2008, The Institute of Noise Control Engineering. | |||||
BibTeX:
@conference{Ghinet2008574, author = {Ghinet, S. and Atalla, N.}, title = {Noise transmission loss of orthotropic sandwich composite panels}, journal = {Institute of Noise Control Engineering of the USA - 23rd National Conference on Noise Control Engineering, NOISE-CON 08 and Sound Quality Symposium, SQS 08}, year = {2008}, volume = {2}, pages = {574-582}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870014468&partnerID=40&md5=4c61f577d6ea4e961b916552d33e85e2} } |
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Hug, F., Drouet, J., Champoux, Y., Couturier, A. and Dorel, S. | Interindividual variability of electromyographic patterns and pedal force profiles in trained cyclists | 2008 | European Journal of Applied Physiology Vol. 104(4), pp. 667-678 |
article | DOI URL |
Abstract: The aim of this study was to determine whether high inter-individual variability of the electromyographic (EMG) patterns during pedaling is accompanied by variability in the pedal force application patterns. Eleven male experienced cyclists were tested at two submaximal power outputs (150 and 250 W). Pedal force components (effective and total forces) and index of mechanical effectiveness were measured continuously using instrumented pedals and were synchronized with surface electromyography signals measured in ten lower limb muscles. The intersubject variability of EMG and mechanical patterns was assessed using standard deviation, mean deviation, variance ratio and coefficient of cross-correlation (R0 with lag time = 0). The results demonstrated a high intersubject variability of EMG patterns at both exercise intensities for biarticular muscles as a whole (and especially for Gastrocnemius lateralis and Rectus femoris) and for one monoarticular muscle (Tibialis anterior). However, this heterogeneity of EMG patterns is not accompanied by a so high intersubject variability in pedal force application patterns. A very low variability in the three mechanical profiles (effective force, total force and index of mechanical effectiveness) was obtained in the propulsive downstroke phase, although a greater variability in these mechanical patterns was found during upstroke and around the top dead center, and at 250 W when compared to 150 W. Overall, these results provide additional evidence for redundancy in the neuromuscular system. © Springer-Verlag 2008. | |||||
BibTeX:
@article{Hug2008667, author = {Hug, F. and Drouet, J.M. and Champoux, Y. and Couturier, A. and Dorel, S.}, title = {Interindividual variability of electromyographic patterns and pedal force profiles in trained cyclists}, journal = {European Journal of Applied Physiology}, year = {2008}, volume = {104}, number = {4}, pages = {667-678}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-53749097052&doi=10.1007%2fs00421-008-0810-y&partnerID=40&md5=bd4e233b8645f3fafb871db237055f39}, doi = {https://doi.org/10.1007/s00421-008-0810-y} } |
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Lemieux, R., Michaud, F., Masson, P., Bellemarre, C., Martin, M., Bernard, M.-È., Fauteux, P., Julien, C., Lalonde-Filion, M., Morier, C., Morin-Guimond, A., Patry, M.-A. and Saint-Pierre, A. | Robotized camera system for real-time coaching of clinicians in emergency room | 2008 | International Journal of Computer Assisted Radiology and Surgery Vol. 3(3-4), pp. 241-248 |
article | DOI URL |
Abstract: Purpose: To compensate for the shortage of emergency specialists and to maintain quality of medical care in remote regions. Methods: Develop and validate the concept of real-time coaching using a robotized camera system ceiling-mounted above a stretcher. Exploit a final prototype to evaluate its impact on surgical procedures under controlled conditions. Results: Preliminary results demonstrate: (1) the system allows a remote practitioner to easily view all surgical procedures used in emergency room, and (2) a specialist can coach a non-specialist to perform a surgical procedure using proper kinesiologic gestual with many individuals surrounding the stretcher. Conclusion: The system could provide help on demand and improve the level of services in trauma medicine for the population of regions where trauma surgeons are unavailable. The system could also decrease medical cost by providing remote support on surgical procedures used to stabilize unstable polytraumatized patients at their arrival in the trauma room. © CARS 2008. | |||||
BibTeX:
@article{Lemieux2008241, author = {Lemieux, R. and Michaud, F. and Masson, P. and Bellemarre, C. and Martin, M. and Bernard, M.-È. and Fauteux, P. and Julien, C. and Lalonde-Filion, M. and Morier, C. and Morin-Guimond, A. and Patry, M.-A. and Saint-Pierre, A.}, title = {Robotized camera system for real-time coaching of clinicians in emergency room}, journal = {International Journal of Computer Assisted Radiology and Surgery}, year = {2008}, volume = {3}, number = {3-4}, pages = {241-248}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-49349085422&doi=10.1007%2fs11548-008-0236-3&partnerID=40&md5=5d592b7933f1904ef94eb15992bdda55}, doi = {https://doi.org/10.1007/s11548-008-0236-3} } |
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Leroy, P., Herzog, P., Berry, A. and Atalla, N. | Experimental assessment of the performance of a 'smart foam' absorber | 2008 | Proceedings - European Conference on Noise Control, pp. 5499-5504 | conference | URL |
Abstract: The signal processing implementation of a hybrid passive/active absorber (smart foam) made up from the combination of a passive absorbent (foam) and a bonded, curved PVDF film, to enhance low frequency performance is considered. Three methods for obtaining the control signal are experimentally compared in the case of a plane wave excitation. Three prototypes of such smart foam have been built and tested in a waveguide (rectangular impedance tube) at frequencies between 100 Hz and 1500Hz. The performances in term of the absorption coefficient and the control input normalized by the incident pressure are presented and discussed, comparing the three methods. The first method uses estimations of the transfer functions between the sources and two microphones in the tube to calculate off-line an optimal filter in the frequency domain. The two other methods are based on a real-time adaptive control using a nFXLMS algorithm, a unidirectional microphone as error sensor, and the primary source signal as reference signal. The control filter is obtained after the initial convergence, using either pure tone disturbance (2nd method) or broad band disturbance (3rd method). | |||||
BibTeX:
@conference{Leroy20085499, author = {Leroy, P.M.J. and Herzog, P. and Berry, A. and Atalla, N.}, title = {Experimental assessment of the performance of a 'smart foam' absorber}, journal = {Proceedings - European Conference on Noise Control}, year = {2008}, pages = {5499-5504}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874862546&partnerID=40&md5=150904d815bd9429e11cd344ae35e359} } |
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McRae, J., Naguib, H. and Atalla, N. | Acoustic performance and compression behaviour of perforated aluminium foam | 2008 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 6929 |
conference | DOI URL |
Abstract: The acoustic performance of multifunctional aluminium foam panels has been studied in this paper. The closed cell foam structure was perforated using hole drilling techniques to produce an open cell structure for use in acoustic applications. Opening the cell structure allows permeability through the foam, thus improving acoustic absorption. The study analyzes the effects of hole size, perforation ratio and foam surface skin on acoustic performance. Mechanical testing was conducted to quantify the reduction in stiffness and strength of the perforated aluminum foam structure. Finally, optimal parameters for use in stiff automotive panel applications are identified. | |||||
BibTeX:
@conference{McRae2008, author = {McRae, J. and Naguib, H.E. and Atalla, N.}, title = {Acoustic performance and compression behaviour of perforated aluminium foam}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2008}, volume = {6929}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-44949096703&doi=10.1117%2f12.776467&partnerID=40&md5=7469687d9031f6526735fac753149e13}, doi = {https://doi.org/10.1117/12.776467} } |
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McRae, J., Naguib, H. and Atalla, N. | Mechanical and acoustic performance of compression molded open cell polypropylene foams | 2008 | Proceedings of the ASME Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS2008 Vol. 1, pp. 76-84 |
conference | DOI URL |
Abstract: The mechanical and acoustic performance of open cell polypropylene (PP) foam has been studied in this paper. The particulate leaching method was used to fabricate the open cell PP samples. Foaming parameters such as salt size and salt/polymer mass ratio were controlled to produce samples with different open cell morphologies. The study analyzes the effects cell size, cell density, and relative density have on mechanical and acoustic performance. Mechanical testing was conducted to quantify stiffness and strength of the open cell PP foams. Optimal cellular morphologies for acoustic absorption and mechanical performance were identified. Copyright © 2008 by ASME. | |||||
BibTeX:
@conference{McRae200876, author = {McRae, J.D. and Naguib, H.E. and Atalla, N.}, title = {Mechanical and acoustic performance of compression molded open cell polypropylene foams}, journal = {Proceedings of the ASME Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS2008}, year = {2008}, volume = {1}, pages = {76-84}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78149390140&doi=10.1115%2fSMASIS2008-447&partnerID=40&md5=c5cdd1b695da3eb7310b782c0df9a1f1}, doi = {https://doi.org/10.1115/SMASIS2008-447} } |
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Muanke, P., Masson, P. and Micheau, P. | Determination of normal force for optimal energy dissipation of harmonic disturbance in a semi-active device | 2008 | Journal of Sound and Vibration Vol. 311(3-5), pp. 633-651 |
article | DOI URL |
Abstract: A semi-active device is presented for vibration control using energy dissipation by dry friction at contact surfaces. The device uses two piezoelectric stack actuators to apply a normal force between a moving mass component and two friction pads. The objective is to adjust the normal force in order to reach the maximal power dissipated. The theoretical optimal normal force is predicted with an analytical model of the device. The normal force generator is modelled using the piezoelectric constitutive equations. The LuGre model is proposed for the dry friction modelling and then reduced to the Coulomb model. The parameters of the spring-mass-damper, force generator and dry friction models were identified experimentally. The dissipated power is obtained from the experimental measurements and presented with respect to the operating parameters (voltage, frequency, excitation force) and the results validate the presented optimal constant normal force to maximize the energy dissipated. © 2007 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Muanke2008633, author = {Muanke, P.B. and Masson, P. and Micheau, P.}, title = {Determination of normal force for optimal energy dissipation of harmonic disturbance in a semi-active device}, journal = {Journal of Sound and Vibration}, year = {2008}, volume = {311}, number = {3-5}, pages = {633-651}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-38749138426&doi=10.1016%2fj.jsv.2007.09.021&partnerID=40&md5=5e396d388cf2f511717428e7dc5d25bf}, doi = {https://doi.org/10.1016/j.jsv.2007.09.021} } |
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Olny, X. and Panneton, R. | Acoustical determination of the parameters governing thermal dissipation in porous media | 2008 | Journal of the Acoustical Society of America Vol. 123(2), pp. 814-824 |
article | DOI URL |
Abstract: In this paper, the question of the acoustical determination of macroscopic thermal parameters used to describe heat exchanges in rigid open-cell porous media subjected to acoustical excitations is addressed. The proposed method is based on the measurement of the dynamic bulk modulus of the material, and analytical inverse solutions derived from different semiphenomenological models governing the thermal dissipation of acoustic waves in the material. Three models are considered: (1) Champoux-Allard model [J. Appl. Phys. 20, 1975-1979 (1991)] requiring knowledge of the porosity and thermal characteristic length, (2) Lafarge model [J. Acoust. Soc. Am. 102, 1995-2006 (1997)] using the same parameters and the thermal permeability, and (3) Wilson model [J. Acoust. Soc. Am. 94, 1136-1145 (1993)] that requires two adjusted parameters. Except for the porosity that is obtained from direct measurement, all the other thermal parameters are derived from the analytical inversion of the models. The method is applied to three porous materials-a foam, a glass wool, and a rock wool-with very different thermal properties. It is shown that the method can be used to assess the validity of the descriptive models for a given material. © 2008 Acoustical Society of America. | |||||
BibTeX:
@article{Olny2008814, author = {Olny, X. and Panneton, R.}, title = {Acoustical determination of the parameters governing thermal dissipation in porous media}, journal = {Journal of the Acoustical Society of America}, year = {2008}, volume = {123}, number = {2}, pages = {814-824}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-38849088096&doi=10.1121%2f1.2828066&partnerID=40&md5=4bda1cba90335f28d4eb4185fd37ad20}, doi = {https://doi.org/10.1121/1.2828066} } |
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Perrot, C., Chevillotte, F. and Panneton, R. | Optimal sound absorbing and manufacturable two-dimensional, hexagonal-like porous structure | 2008 | Proceedings of Meetings on Acoustics Vol. 4 |
conference | DOI URL |
Abstract: Results from a numerical study examining micro-macro relations linking local geometry parameters to sound absorption properties are presented. For an hexagonal structure of solid fibers, the porosity f, the thermal characteristic length ?', the static viscous permeability ? 0, the tortuosity a 8, the viscous characteristic length ?, and the sound absorption coefficient are computed. Numerical solutions of the steady Stokes and electrical equations are employed to provide ? 0, a 8, and ?. Hybrid estimates based on direct numerical evaluation of f, ?', ? 0, a 8, ? and the analytical model derived by Johnson, Allard, and Champoux are used to relate varying (i) throat size, (ii) pore size, and (iii) fibers cross-section shapes to the sound absorption spectrum. The result of this paper tends to demonstrate the important effect of throat size in the sound absorption level, cell size in the sound absorption frequency selectivity, fibers cross-section shape in the porous material weight reduction. In a hexagonal porous structure with solid fibers, the sound absorption level will tend to be maximized with a 48 ± 10 µm throat size corresponding to an intermediate resistivity, a 13 ± 8 µm fiber radius associated with relatively small inter-fiber distances, and convex triangular cross-section shape fibers allowing weight reduction. © 2008 Acoustical Society of America. | |||||
BibTeX:
@conference{Perrot2008, author = {Perrot, C. and Chevillotte, F. and Panneton, R.}, title = {Optimal sound absorbing and manufacturable two-dimensional, hexagonal-like porous structure}, journal = {Proceedings of Meetings on Acoustics}, year = {2008}, volume = {4}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865988257&doi=10.1121%2f1.2972138&partnerID=40&md5=f4992799b16d71f0ecd11637aba4b8a8}, doi = {https://doi.org/10.1121/1.2972138} } |
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Perrot, C., Chevillotte, F., Panneton, R., Allard, J.-F. and Lafarge, D. | On the dynamic viscous permeability tensor symmetry | 2008 | Journal of the Acoustical Society of America Vol. 124(4), pp. EL210-EL217 |
article | DOI URL |
Abstract: Based on a direct generalization of a proof given by Torquato for symmetry property in static regime, this express letter clarifies the reasons why the dynamic permeability tensor is symmetric for spatially periodic structures having symmetrical axes which do not coincide with orthogonal pairs being perpendicular to the axis of three-, four-, and sixfold symmetry. This somewhat nonintuitive property is illustrated by providing detailed numerical examples for a hexagonal lattice of solid cylinders in the asymptotic and frequency dependent regimes. It may be practically useful for numerical implementation validation andor convergence assessment. © 2008 Acoustical Society of America. | |||||
BibTeX:
@article{Perrot2008, author = {Perrot, C. and Chevillotte, F. and Panneton, R. and Allard, J.-F. and Lafarge, D.}, title = {On the dynamic viscous permeability tensor symmetry}, journal = {Journal of the Acoustical Society of America}, year = {2008}, volume = {124}, number = {4}, pages = {EL210-EL217}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-53949101386&doi=10.1121%2f1.2968300&partnerID=40&md5=b8866ff4dee5cfbf4772886690ef1882}, doi = {https://doi.org/10.1121/1.2968300} } |
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Perrot, C., Chevillotte, F. and Panneton, R. | Dynamic viscous permeability of an open-cell aluminum foam: Computations versus experiments | 2008 | Journal of Applied Physics Vol. 103(2) |
article | DOI URL |
Abstract: Is it possible to find a two-dimensional (2D) periodic unit cell representative of the dynamic viscous dissipation properties of a real porous media? This is a challenging question addressed in this paper through a review of tools and methods of experimental and computational micro(poro)mechanics. The combination of advanced experimental imaging and numerical homogenization techniques provides a unique opportunity to understand and assess the limits of two-dimensional models of microstructures, as a potential basis for the engineering prediction of macroscopic properties of acoustical materials. This is illustrated for a real sample of open-cell aluminum foam. The conclusion, based on this analysis, is that the 2D periodic foam model geometry provides a reliable estimate of the dynamic permeability, except in the low frequency range. This is not surprising because in the 2D periodic foam model geometry, ligaments are always perpendicular to the flow direction, thus decreasing artificially the static permeability of the viscous flow. © 2008 American Institute of Physics. | |||||
BibTeX:
@article{Perrot2008, author = {Perrot, C. and Chevillotte, F. and Panneton, R.}, title = {Dynamic viscous permeability of an open-cell aluminum foam: Computations versus experiments}, journal = {Journal of Applied Physics}, year = {2008}, volume = {103}, number = {2}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-38849114282&doi=10.1063%2f1.2829774&partnerID=40&md5=c7238a7d5a1369721a4bcf54d477955f}, doi = {https://doi.org/10.1063/1.2829774} } |
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Perrot, C., Chevillotte, F., Panneton, R. and Olny, X. | Periodic unit cell reconstruction of porous media: Acoustic properties of an open cell aluminum foam | 2008 | MetFoam 2007 - Proceedings of the 5th International Conference on Porous Metals and Metallic Foams, pp. 433-436 | conference | URL |
Abstract: The issue of reconstructing an idealized periodic unit-cell of porous medium is examined in this paper, thanks to a sample of open cell aluminum foam that has been analyzed by a desktop of X-ray computed microtomography. Cellular shape and size properties are directly measured on selected cells of the imaged sample. This is used in order to reconstruct a porous medium by means of a periodic unit cell: a tetrakaidecahedron with ligaments of triangular cross-sections, whose characteristic dimensions have been identified experimentally. Averaged geometrical properties of the real experimental sample and the reconstructed one are then compared. The porosity and the thermal characteristic length are found to be in good agreement. This provides us with an idealized periodic unit cell of the real porous media. It can be used to solve in it the partial differential equations governing the dissipation and propagation phenomena of acoustic waves in order to study the micro-physical basis of the acoustical macro-behavior. | |||||
BibTeX:
@conference{Perrot2008433, author = {Perrot, C. and Chevillotte, F. and Panneton, R. and Olny, X.}, title = {Periodic unit cell reconstruction of porous media: Acoustic properties of an open cell aluminum foam}, journal = {MetFoam 2007 - Proceedings of the 5th International Conference on Porous Metals and Metallic Foams}, year = {2008}, pages = {433-436}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-56549088806&partnerID=40&md5=6da05120ae7b1e68e826977746c5e8fb} } |
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Perrot, C., Chevillotte, F. and Panneton, R. | Optimal sound absorbing and manufacturable two-dimensional, hexagonal-like porous structure | 2008 | Proceedings - European Conference on Noise Control, pp. 7-10 | conference | URL |
Abstract: Results from a numerical study examining micro-macro relations linking local geometry parameters to sound absorption properties are presented. For an hexagonal structure of solid fibers, the porosity f, the thermal characteristic length ?', the static viscous permeability ?0, the tortuosity a8, the viscous characteristic length ?, and the sound absorption coefficient are computed. Numerical solutions of the steady Stokes and electrical equations are employed to provide ?0, a8, and ?. Hybrid estimates based on direct numerical evaluation of f, ?', ?0, a8, ? and the analytical model derived by Johnson, Allard, and Champoux are used to relate varying (i) throat size, (ii) pore size, and (iii) fibers cross-section shapes to the sound absorption spectrum. The result of this paper tends to demonstrate the important effect of throat size in the sound absorption level, cell size in the sound absorption frequency selectivity, fibers cross-section shape in the porous material weight reduction. In a hexagonal porous structure with solid fibers, the sound absorption level will tend to be maximized with a 48 ± 10 µm throat size corresponding to an intermediate resistivity, a 13 ± 8 µm fiber radius associated with relatively small inter-fiber distances, and convex triangular cross-section shape fibers allowing weight reduction. | |||||
BibTeX:
@conference{Perrot20087, author = {Perrot, C. and Chevillotte, F. and Panneton, R.}, title = {Optimal sound absorbing and manufacturable two-dimensional, hexagonal-like porous structure}, journal = {Proceedings - European Conference on Noise Control}, year = {2008}, pages = {7-10}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874828688&partnerID=40&md5=83f87bcfa1f43cc7250a70efe00ce1d3} } |
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Perrot, C., Chevillotte, F. and Panneton, R. | Bottom-up approach for microstructure optimization of sound absorbing materials | 2008 | Journal of the Acoustical Society of America Vol. 124(2), pp. 940-948 |
article | DOI URL |
Abstract: Results from a numerical study examining micro-/macrorelations linking local geometry parameters to sound absorption properties are presented. For a hexagonal structure of solid fibers, the porosity f, the thermal characteristic length ?', the static viscous permeability k 0, the tortuosity a8, the viscous characteristic length ?, and the sound absorption coefficient are computed. Numerical solutions of the steady Stokes and electrical equations are employed to provide k0, a8, and ?. Hybrid estimates based on direct numerical evaluation of f, ?', k0, a8, ?, and the analytical model derived by Johnson, Allard, and Champoux are used to relate varying (i) throat size, (ii) pore size, and (iii) fibers' cross-section shapes to the sound absorption spectrum. The result of this paper tends to demonstrate the important effect of throat size in the sound absorption level, cell size in the sound absorption frequency selectivity, and fibers' cross-section shape in the porous material weight reduction. In a hexagonal porous structure with solid fibers, the sound absorption level will tend to be maximized with a 48±10 µm throat size corresponding to an intermediate resistivity, a 13±8 µm fiber radius associated with relatively small interfiber distances, and convex triangular cross-section shape fibers allowing weight reduction. © 2008 Acoustical Society of America. | |||||
BibTeX:
@article{Perrot2008940, author = {Perrot, C. and Chevillotte, F. and Panneton, R.}, title = {Bottom-up approach for microstructure optimization of sound absorbing materials}, journal = {Journal of the Acoustical Society of America}, year = {2008}, volume = {124}, number = {2}, pages = {940-948}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-49249093904&doi=10.1121%2f1.2945115&partnerID=40&md5=f7899f8d73404f0cd132ce22b8ad73a3}, doi = {https://doi.org/10.1121/1.2945115} } |
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Pilon, D., Labbé, S., Touzin, J.-F., Marsan, B., Panneton, R., Fréchette, L. and Gros, E. | Characterization of high surface area open-cell metal foams and application to thermal management and electrochemistry | 2008 | MetFoam 2007 - Proceedings of the 5th International Conference on Porous Metals and Metallic Foams, pp. 501-504 | conference | URL |
Abstract: MetaFoam is an open-cell metal foam manufacturer which commercializes its novel materials in various fields of applications, including thermal management and electrochemistry. The powder metallurgy based production process, developed by the National Research Council Canada, leads to high process repeatability combined with the highest specific surface area and the lowest production costs in the industry. The main challenge is to identify applications that can fully take advantage of this material's unique combination of properties. With that in mind, many test benches have been developed to characterize the physical properties and performance of these open-cell metal foams. In the following, test benches are detailed and characterization results are presented for copper and nickel foams manufactured by MetaFoam. Measured characteristics include 1) thermal conductivity, 2) air and water permeability, pressure drop, and Nusselt number, and 3) roughness factor and electrode over-potential. It is shown that MetaFoam's open-cell materials have distinct advantages in many fields of applications, which leads to promising business opportunities because of its low production costs and mass production capabilities. | |||||
BibTeX:
@conference{Pilon2008501, author = {Pilon, D. and Labbé, S. and Touzin, J-F. and Marsan, B. and Panneton, R. and Fréchette, L. and Gros, E.}, title = {Characterization of high surface area open-cell metal foams and application to thermal management and electrochemistry}, journal = {MetFoam 2007 - Proceedings of the 5th International Conference on Porous Metals and Metallic Foams}, year = {2008}, pages = {501-504}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-56549119804&partnerID=40&md5=ea4f637ae0e05b7b86a1b7bbfd6cfcbe} } |
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Quaegebeur, N. and Chaigne, A. | Nonlinear vibrations of loudspeaker-like structures | 2008 | Journal of Sound and Vibration Vol. 309(1-2), pp. 178-196 |
article | DOI URL |
Abstract: During high amplitudes of vibration, nonlinearities affect the electroacoustical behavior of electrodynamic transducers and are responsible for audible distortions. We distinguish two types of nonlinearities: electrical and mechanical. In this study, attention is paid to the mechanical and geometrical properties of loudspeaker-like structures. The loudspeaker is viewed as a combination of an annular plate with a circular plate. Nonlinear vibrations of such a structure are investigated, using the dynamic analog of the Von-Kármán equations. Furthermore, the influence of both material properties and geometrical parameters is studied. It is shown that nonlinear effects can be substantially reduced by choosing appropriate material and geometrical parameters. © 2007 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Quaegebeur2008178, author = {Quaegebeur, N. and Chaigne, A.}, title = {Nonlinear vibrations of loudspeaker-like structures}, journal = {Journal of Sound and Vibration}, year = {2008}, volume = {309}, number = {1-2}, pages = {178-196}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35448929915&doi=10.1016%2fj.jsv.2007.06.040&partnerID=40&md5=3dcc6113027f3c66defc714b347982c8}, doi = {https://doi.org/10.1016/j.jsv.2007.06.040} } |
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Quaegebeur, N. and Chaigne, A. | Mechanical resonances and geometrical nonlinearities in electrodynamic loudspeakers | 2008 | AES: Journal of the Audio Engineering Society Vol. 56(6), pp. 462-472 |
article | URL |
Abstract: For high amplitudes of vibration loudspeakers are subject to nonlinear phenomena that are responsible for audible distortions such as intermodulation or harmonic distortion. The lowfrequency model uses nonlinear lumped parameters and is only valid around the first mechanical resonance since it assumes a rigid body movement. In the present study a model of the electromechanical problem including the effects of diaphragm modal resonances using the state-space formalism is proposed. No approximation of the nonlinear behavior of the electrical parameters is necessary for the direct calculation of the vibration pattern. The model is developed for one degree of freedom (plane piston approximation) and then expanded to an n-degree-of-freedom system. allowing one to model mechanical resonances and geometrical nonlinearities of the system. | |||||
BibTeX:
@article{Quaegebeur2008462, author = {Quaegebeur, N. and Chaigne, A.}, title = {Mechanical resonances and geometrical nonlinearities in electrodynamic loudspeakers}, journal = {AES: Journal of the Audio Engineering Society}, year = {2008}, volume = {56}, number = {6}, pages = {462-472}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-46749128902&partnerID=40&md5=266c6d7d68b51a74d94b36e48e738c70} } |
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Salissou, Y. and Panneton, R. | Quantifying the through-thickness asymmetry of sound absorbing porous materials | 2008 | Journal of the Acoustical Society of America Vol. 124(2), pp. EL28-EL33 |
article | DOI URL |
Abstract: A method to quantify the through-thickness asymmetry of a sound absorbing porous material is proposed and discussed. Its calculation only requires impedance tube measurements of the acoustical surface impedance performed on both sides of the tested material. The method may be used for quality control or to assess the level of asymmetry of the material in terms of its acoustic properties. As a first validation, a two-layered porous system seen as an equivalent asymmetrical single porous layer with a sudden change in its physical properties is studied. From this study, a criterion of asymmetry is suggested and experimentally tested. © 2008 Acoustical Society of America. | |||||
BibTeX:
@article{Salissou2008, author = {Salissou, Y. and Panneton, R.}, title = {Quantifying the through-thickness asymmetry of sound absorbing porous materials}, journal = {Journal of the Acoustical Society of America}, year = {2008}, volume = {124}, number = {2}, pages = {EL28-EL33}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-49249092479&doi=10.1121%2f1.2947625&partnerID=40&md5=c31b8fd5700bf7150bfe4c02a37a4857}, doi = {https://doi.org/10.1121/1.2947625} } |
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Salissou, Y. and Panneton, R. | Pressure/mass method to measure open porosity of porous solids | 2008 | Canadian Acoustics - Acoustique Canadienne Vol. 36(3), pp. 142-143 |
article | URL |
Abstract: A new method is proposed, to measure the open porosity of porous solids. The method needs a simple apparatus and its accuracy is predictable from the knowledge of the total bulk volume of the tested porous sample. Volume needs to be evaluated first, to apply the proposed method. The method demonstrates the minimum bulk volume per balance readability, as a function of open porosity for different operating conditions. It shows that larger bulk volume, larger high pressure, and gas with larger density are desirable to increase the applicability of the method and to detect open porosity closer to unity. | |||||
BibTeX:
@article{Salissou2008142, author = {Salissou, Y. and Panneton, R.}, title = {Pressure/mass method to measure open porosity of porous solids}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2008}, volume = {36}, number = {3}, pages = {142-143}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-54949138746&partnerID=40&md5=b9575ba84a50d5b3a0fa52ba0c05eeaf} } |
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Sgard, F., Nelisse, H., Atalla, N., Amedin, C. and Oddo, R. | A hybrid SEA/image sources approach for the prediction of the insertion loss of enclosures | 2008 | Proceedings - European Conference on Noise Control, pp. 3287-3292 | conference | URL |
Abstract: Enclosures are a classical solution to reduce the sound exposure of workers to the noise radiated by machinery. Their acoustic design can be achieved with the help of predictive tools based on simple analytical tools or sophisticated numerical deterministic models. However, there is no simple and fast tool allowing to account for the complexity of the enclosure configuration, capable of better simulating the non-diffuse nature of the field inside the enclosure and covering the typical frequency range [100Hz; 5000Hz]. This paper presents the development of such a tool for the prediction of the acoustic performance of enclosures. It is based on a hybrid model: the statistical energy analysis (SEA) for the sound transmission across the various elements of the enclosure and the method of image sources for the sound field inside the enclosure. The approach is validated by comparing calculation and experimental results carried out in a semi-anechoic room on rectangular and L-shape enclosures for several inner source locations. The effect of an opening is also investigated. The comparisons between the models and the experimental results show a good agreement for most of the tested configurations. | |||||
BibTeX:
@conference{Sgard20083287, author = {Sgard, F.C. and Nelisse, H. and Atalla, N. and Amedin, C.K. and Oddo, R.}, title = {A hybrid SEA/image sources approach for the prediction of the insertion loss of enclosures}, journal = {Proceedings - European Conference on Noise Control}, year = {2008}, pages = {3287-3292}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874908478&partnerID=40&md5=3e003628061e7ef6f8818121bed813d7} } |
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Ahmed, M., Wang, C., Park, C. and Atalla, N. | Microcellular ceramic foams: Manufacturing and study of acoustical properties | 2007 | SAE Technical Papers | article | DOI URL |
Abstract: A novel processing method for fabricating high porosity microcellular ceramic foams for sound absorption applications has been developed. The strategy for fabricating the ceramic foams involves: (i) forming some shapes using a mixture of preceramic polymer and expandable microspheres by a conventional ceramic forming method, (ii) foaming the compact by heating, (iii) cross-linking the foamed body, and (iv) transforming the foamed body into ceramic foams by pyrolysis. By controlling the microsphere content and that of the base elastomer, it was possible to adjust the porosity with a very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9 × 108 - 1.6 × 109 cells/cm3) and desired expansion ratios (3 - 6 folds). Sound absorption testing has been performed using ASTM C-384 standard test. The preliminary results show that ceramic foams are candidate sound absorption materials. Copyright © 2007 SAE International. | |||||
BibTeX:
@article{Ahmed2007, author = {Ahmed, M.Y.S. and Wang, C. and Park, C.B. and Atalla, N.}, title = {Microcellular ceramic foams: Manufacturing and study of acoustical properties}, journal = {SAE Technical Papers}, year = {2007}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877428502&doi=10.4271%2f2007-01-2187&partnerID=40&md5=999d0b7cab070fdb6be243a2b7f6d2f0}, doi = {https://doi.org/10.4271/2007-01-2187} } |
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Allard, J., Brouard, B., Atalla, N. and Ghinet, S. | Excitation of soft porous frame resonances and evaluation of rigidity coefficients | 2007 | Journal of the Acoustical Society of America Vol. 121(1), pp. 78-84 |
article | DOI URL |
Abstract: Recent works have been performed concerning the guided elastic waves in soft porous elastic frames and the related normal displacement of the surface generated by a mechanical excitation. In this work, the mechanical excitation is replaced by a monopole acoustic field in air above the porous structure. Two cases are considered: a frame bonded on a rigid impervious layer and a free frame. The normal and the radial velocity induced by the monopole field at the surface of the frame is predicted with the Biot theory and the Sommerfeld representation of the monopole field. Measurements are performed with a laser vibrometer on a urethane foam. It is shown that the characterization of the excited modes can lead to an evaluation of the rigidity coefficients of the frames at acoustical frequencies. © 2007 Acoustical Society of America. | |||||
BibTeX:
@article{Allard200778, author = {Allard, J.F. and Brouard, B. and Atalla, N. and Ghinet, S.}, title = {Excitation of soft porous frame resonances and evaluation of rigidity coefficients}, journal = {Journal of the Acoustical Society of America}, year = {2007}, volume = {121}, number = {1}, pages = {78-84}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33846223292&doi=10.1121%2f1.2387127&partnerID=40&md5=f00c48fa5969ebeba6093c779ad3c1c9}, doi = {https://doi.org/10.1121/1.2387127} } |
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Amichi, K. and Atalla, N. | A new 3D finite element for sandwich structures with a viscoelastic core | 2007 | Canadian Acoustics - Acoustique Canadienne Vol. 35(3), pp. 198-199 |
article | URL |
Abstract: A new sandwich finite element model has been developed for sandwich structures with a viscoelastic core. The model allows for both symmetrical and unsymmetrical configurations. The rotational influence of the transversal shearing in the core on the skins behaviors ensure a displacements consistency over the interfaces between the viscoelastic core and the elastic skins resulting in an accurate representations of the physics. Validations are performed versus both analytical and classical Finite elements models using MSC/Nastran®(Nastran). The Nastran model uses solid finite elements for the core and shell finite elements for the skins. The proposed element sandwich is accurate for the modeling of the studied laminated steels. | |||||
BibTeX:
@article{Amichi2007198, author = {Amichi, K. and Atalla, N.}, title = {A new 3D finite element for sandwich structures with a viscoelastic core}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2007}, volume = {35}, number = {3}, pages = {198-199}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35448933165&partnerID=40&md5=4ca1db720fbd5097e92b475a2aa8f28e} } |
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Atalla, N. and Sgard, F. | Modeling of perforated plates and screens using rigid frame porous models | 2007 | Journal of Sound and Vibration Vol. 303(1-2), pp. 195-208 |
article | DOI URL |
Abstract: There are several models and approaches for predicting the acoustic response of perforated plates and screens. Classical models are devoted to specific configurations: particular geometrical parameters including the size and shape of the perforations, excitations type, mounting of the screen (bonded vs. free), and interfacing media involved in multilayers sound packages. This paper reviews these models and presents a simple and general model that can handle easily and automatically the miscellaneous configurations in the context of the transfer matrix method. In particular, it is shown that a perforated plate or screen can be modeled as an equivalent fluid following the Johnson-Allard approach with an equivalent tortuosity. This equivalent tortuosity is shown to depend on the media interfacing with the perforated system. Experimental results depicting various practical configurations are shown to corroborate the validity of the proposed model and to evaluate its performance compared to classical ones. © 2007 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Atalla2007195, author = {Atalla, N. and Sgard, F.}, title = {Modeling of perforated plates and screens using rigid frame porous models}, journal = {Journal of Sound and Vibration}, year = {2007}, volume = {303}, number = {1-2}, pages = {195-208}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33947647834&doi=10.1016%2fj.jsv.2007.01.012&partnerID=40&md5=bf2de309e97951c3f55d59b4ce776144}, doi = {https://doi.org/10.1016/j.jsv.2007.01.012} } |
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Champoux, Y., Richard, S. and Drouet, J.-M. | Bicycle structural dynamics | 2007 | Sound and Vibration Vol. 41(7), pp. 16-24 |
article | URL |
Abstract: Research group at the Université de Sherbrooke VéIUS commits to help the bicycle industry by developing materials, technologies, and design procedures, which improves the comfort and durability of the bicycle. Results of tests with a cyclist signifies that both (single input multiple output) SIMO and (multiple input multiple output) MIMO analyses give similar results for natural frequencies and mode shapes. The technique of operating deflection shapes (ODS) is very useful for understanding and evaluating the real-life dynamic behavior of a machine component or an entire structure. The aim of European standards EN 14781 and EN 14766 is to ensure that bicycles will be safe as practically possible. The study shows that an appropriate curve and the hot-spot technique can be used to predict the fatigue such as life of bike frames and components fabricated with thin, circular, and aluminum tubes. | |||||
BibTeX:
@article{Champoux200716, author = {Champoux, Y. and Richard, S. and Drouet, J.-M.}, title = {Bicycle structural dynamics}, journal = {Sound and Vibration}, year = {2007}, volume = {41}, number = {7}, pages = {16-24}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548773870&partnerID=40&md5=0a81e780da2b8d4af1ec2451b295e859} } |
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Chevillotte, F., Panneton, R., Wojtowicki, J.-L. and Chaut, C. | Characterization of the bulk elastic properties of expanding foams from impedance tube absorption tests | 2007 | SAE Technical Papers | article | DOI URL |
Abstract: A method is presented to determine the bulk elastic properties of isotropic elastic closed-cell foams from impedance tube sound absorption tests. For such foams, resonant sound absorption is generally observed, where acoustic energy is transformed into mechanical vibration, which in turn is dissipated into heat due to structural damping. This paper shows how the bulk Young's modulus and damping loss factor can be deduced from the resonant absorption. Also, an optimal damping loss factor yielding 100% of absorption at the first resonance is defined from the developed theory. It is shown how this optimal factor can be used to properly design efficient sound absorbing treatments. The method is experimentally tested on one expanding closed-cell foam to find its elastic properties. Using the found properties, sound absorption predictions using an equivalent solid model with and without surface absorption are compared to measurements. Excellent correlations are obtained when considering surface absorption. Copyright © 2007 SAE International. | |||||
BibTeX:
@article{Chevillotte2007, author = {Chevillotte, F. and Panneton, R. and Wojtowicki, J.-L. and Chaut, C.}, title = {Characterization of the bulk elastic properties of expanding foams from impedance tube absorption tests}, journal = {SAE Technical Papers}, year = {2007}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877425814&doi=10.4271%2f2007-01-2191&partnerID=40&md5=f5edb4f587fc38b29543375908c7bbd8}, doi = {https://doi.org/10.4271/2007-01-2191} } |
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Chevillotte, F. and Panneton, R. | Impedance tube characterization of elastic properties of expanding foams | 2007 | Canadian Acoustics - Acoustique Canadienne Vol. 35(3), pp. 158-159 |
article | URL |
Abstract: A method was proposed to determine the bulk elastic properties of soft equivalent solids or closed cell foams from simple impedance tube absorption tests. Development of the method is based on sound absorption measurements, for the characterization of the bulk elastic properties of closed-cell foams or those from heat expanding foam process. The theory behind the method is first reminded for the sliding edge condition for which the bulk's modulus and damping loss factor can be deduced. The method has been extended to the bonded edge condition which additionally allows the identification of the Poisson's ratio. The method is experimentally tested for characterizing the bulk elastic properties of foam with the bonded edge condition. The accuracy of the method relies mostly on the proper control of the mounting conditions in the impedance tube. | |||||
BibTeX:
@article{Chevillotte2007158, author = {Chevillotte, F. and Panneton, R.}, title = {Impedance tube characterization of elastic properties of expanding foams}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2007}, volume = {35}, number = {3}, pages = {158-159}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35448978276&partnerID=40&md5=0e8129d3602c6265ab41e0f5e8bf2be3} } |
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Chevillotte, F. and Panneton, R. | Elastic characterization of closed cell foams from impedance tube absorption tests | 2007 | Journal of the Acoustical Society of America Vol. 122(5), pp. 2653-2660 |
article | DOI URL |
Abstract: A method is presented to determine the bulk elastic properties of isotropic elastic closed-cell foams from impedance tube sound absorption tests. For such foams, a resonant sound absorption is generally observed, where acoustic energy is transformed into mechanical vibration, which in turn is dissipated into heat due to structural damping. This article shows how the bulk Young's modulus, Poisson's ratio, and damping loss factor can be deduced from the resonant absorption. Also, an optimal damping loss factor yielding 100% of absorption at the first resonance is defined from the developed theory. The method is introduced for a sliding edge condition which is an ideal condition. Then, the method is extended to a bonded edge condition which is more easily achievable and additionally enables the identification of the Poisson's ratio. The method is experimentally tested on expanding closed-cell foams to find their elastic properties in both cases. Using the found properties, sound absorption predictions using an equivalent solid model with and without surface absorption are compared to measurements. Good correlations are obtained when considering surface absorption. © 2007 Acoustical Society of America. | |||||
BibTeX:
@article{Chevillotte20072653, author = {Chevillotte, F. and Panneton, R.}, title = {Elastic characterization of closed cell foams from impedance tube absorption tests}, journal = {Journal of the Acoustical Society of America}, year = {2007}, volume = {122}, number = {5}, pages = {2653-2660}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35448974690&doi=10.1121%2f1.2783126&partnerID=40&md5=250f3de2695b5d0b5f0220c09410e118}, doi = {https://doi.org/10.1121/1.2783126} } |
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Couillard, M., Micheau, P. and Masson, P. | Frictionally damped SDOF oscillator: Experimental realization and friction modeling for small displacements | 2007 | Proceedings of the 9th IASTED International Conference on Control and Applications, CA 2007, pp. 337-342 | conference | URL |
Abstract: The damping of structural vibrations using dry friction is an effective control method for many vibration problems. The strong nonlinear nature of friction has however made the theoretical and experimental investigations much more difficult than for linear control methods. This paper first outlines an experimental setup implementing an ideal frictionally damped Single-Degree-Of-Freedom (SDOF) oscillator through the use of an electrodynamic shaker to study friction damping. By relating the shaker current to the force input and including the shaker armature dynamics in the modelling of the experimental setup, it is shown that the ideal frictionally damped SDOF can be realized. The second part of this paper intends to determine a suitable friction model for small amplitude (<100µm) frictionally damped vibrations. Two friction models are presented, which are the KFM algebraic model and the LuGre dynamic model. Experimental results are then compared to simulation results to show that the LuGre dynamic model captures very well the behaviour of friction for small amplitude vibrations in contrast with the KFM algebraic model. | |||||
BibTeX:
@conference{Couillard2007337, author = {Couillard, M. and Micheau, P. and Masson, P.}, title = {Frictionally damped SDOF oscillator: Experimental realization and friction modeling for small displacements}, journal = {Proceedings of the 9th IASTED International Conference on Control and Applications, CA 2007}, year = {2007}, pages = {337-342}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-54949117564&partnerID=40&md5=af033734426daf696e2411d5d1329851} } |
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Cuerrier, J.-P., Paré, D., Beaudoin, A.-J., Smeesters, C. and Champoux, Y. | A new segment length measurement method [Une nouvelle méthode de mesure de longueurs segmentaires] | 2007 | Science and Sports Vol. 22(3-4), pp. 149-154 |
article | DOI URL |
Abstract: Aims: To develop a faster segment length measurement method than the classical one proposed by the ISAK without modifying the nature and accuracy of the measurements. Methods: Nine segment lengths were chosen and evaluated in 12 subjects with the ISAK method as the "gold standard". The method proposed herein included the marking of anatomical landmarks on the skin and the scanning of these landmarks with a digitizing arm used in computer aided design of mechanical parts. In order to obtain acceptable data, the subject had to stand in a stabilizing device conceived exclusively for this purpose. Results: Paired T-tests between data collected from both methods indicates that a significant difference exists only for the forearm measurement (P = 0.009). The new method is therefore adequate for all segment lengths except at the forearm, where prosupination must be standardized. Conclusion: The time saved with this new method, which is its main advantage, was estimated at 42% in these settings and increases with the number of length measurements on each subject. The proposed method is thus well suited for large measurement volumes or if the time spent with the subjects implies significant costs. © 2007 Elsevier Masson SAS. All rights reserved. | |||||
BibTeX:
@article{Cuerrier2007149, author = {Cuerrier, J.-P. and Paré, D. and Beaudoin, A.-J. and Smeesters, C. and Champoux, Y.}, title = {A new segment length measurement method [Une nouvelle méthode de mesure de longueurs segmentaires]}, journal = {Science and Sports}, year = {2007}, volume = {22}, number = {3-4}, pages = {149-154}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547850199&doi=10.1016%2fj.scispo.2007.04.006&partnerID=40&md5=0f6fa393cb5f8e657e64b029b58da5df}, doi = {https://doi.org/10.1016/j.scispo.2007.04.006} } |
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Delas, O., Berry, A., Masson, P. and Pasco, Y. | Optimizing the thickness of piezoceramic actuators for bending vibration of planar structures | 2007 | Journal of Intelligent Material Systems and Structures Vol. 18(11), pp. 1191-1201 |
article | DOI URL |
Abstract: An analytical approach is proposed to optimize the thickness of piezoceramic (PZT) actuators bonded on structures for active shape, noise, or vibration control. The optimal thickness corresponds to maximal mechanical coupling between the PZT actuator and the substrate. The analysis is carried out for a planar geometry, considering a square simply supported flexural plate with a square and a centered PZT actuator bonded either in symmetric or asymmetric configuration. Optimal thicknesses obtained from explicit analytical expressions are compared with finite element (FE) results for various substrate thicknesses and for various values of actuator coverage ratio. Static and dynamic strain profiles through the thickness of the plate-actuator system are plotted. Laboratory experiments are carried out on aluminum and steel plates with free and clamped boundary conditions to verify the analytical and FE predictions in terms of optimal PZT actuator thickness. © SAGE Publications 2007. | |||||
BibTeX:
@article{Delas20071191, author = {Delas, O. and Berry, A. and Masson, P. and Pasco, Y.}, title = {Optimizing the thickness of piezoceramic actuators for bending vibration of planar structures}, journal = {Journal of Intelligent Material Systems and Structures}, year = {2007}, volume = {18}, number = {11}, pages = {1191-1201}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35548962359&doi=10.1177%2f1045389X07082381&partnerID=40&md5=61dd1663b034188e2481765c9cb784b5}, doi = {https://doi.org/10.1177/1045389X07082381} } |
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Desbiens, J.-P. and Masson, P. | ArF excimer laser micromachining of Pyrex, SiC and PZT for rapid prototyping of MEMS components | 2007 | Sensors and Actuators, A: Physical Vol. 136(2), pp. 554-563 |
article | DOI URL |
Abstract: The ablation process has been characterized in the past for a number of laser sources in silicon (Si) micromachining. However, very few results can be found in the literature for excimer laser technology at 193 nm on Si and even fewer for other materials like piezoceramics (PZT) and silicon carbide (SiC). This work presents a parametric study of the dynamic interaction between the machining parameters involved in the ablation of materials with an ArF excimer laser using a mask dragging approach. The influence of the fluence, the repetition rate of the laser and the linear speed of the sample on the etch rate of material are quantified by experimental results for three different materials (Si, PZT and Pyrex). The main tendencies are discussed and supported with experimental measurement of trench profiles. The results obtained from ablation are then related to the optical and mechanical properties of materials. The interdependence between machining parameters, materials properties and the etch rate of materials is demonstrated. Optimal ranges of parameters are identified and then used to micromachine SiC, in addition to the previous materials. Two case studies are presented to demonstrate the potential complementarity of excimer laser micromachining systems with conventional lithographic microfabrication techniques for MEMS prototyping. © 2007 Elsevier B.V. All rights reserved. | |||||
BibTeX:
@article{Desbiens2007554, author = {Desbiens, J.-P. and Masson, P.}, title = {ArF excimer laser micromachining of Pyrex, SiC and PZT for rapid prototyping of MEMS components}, journal = {Sensors and Actuators, A: Physical}, year = {2007}, volume = {136}, number = {2}, pages = {554-563}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34247616734&doi=10.1016%2fj.sna.2007.01.002&partnerID=40&md5=551c3acc8c6f54211b81cfffd904714a}, doi = {https://doi.org/10.1016/j.sna.2007.01.002} } |
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Duvareille, C., Lafrance, M., Samson, N., St-Hilaire, M., Pladys, P., Micheau, P., Bournival, V., Langlois, C. and Praud, J.-P. | Effects of hypoxia and hypercapnia on nonnutritive swallowing in newborn lambs | 2007 | Journal of Applied Physiology Vol. 103(4), pp. 1180-1188 |
article | DOI URL |
Abstract: The aim of the present study was to investigate the effect of hypercapnia and hypoxia on apnea and nonnutritive swallowing (NNS) frequency, as well as on the coordination between NNS and phases of the respiratory cycle in newborn lambs, while taking into account the potential effects of states of alertness. Six lambs were chronically instrumented for recording electroencephalogram, eye movements, diaphragm and thyroarytenoid muscle (a glottal adductor) activity, nasal airflow, and electrocardiogram. Polysomnographic recordings were performed in nonsedated lambs exposed to air (control), 10% O2, and 5% CO 2 in a random order at 3, 4, and 5 days of age. Although hypercapnia decreased apnea frequency in wakefulness and active sleep (P = 0.002 vs. air and hypoxia), hypoxia had no significant effect on apnea. In addition, although hypercapnia increased NNS frequency during wakefulness and quiet sleep (P < 0.005 vs. air and hypoxia), hypoxia tended to decrease NNS frequency. Finally, only hypercapnia altered NNS-breathing coordination by increasing NNS at the transition from inspiration to expiration (ie-type NNS; P < 0.001 vs. air and hypoxia). In conclusion, whereas hypercapnia increases overall NNS frequency by specifically increasing ie-type NNS, hypoxia has the inverse tendency. Results were identical in all three states of alertness. Copyright © 2007 the American Physiological Society. | |||||
BibTeX:
@article{Duvareille20071180, author = {Duvareille, C. and Lafrance, M. and Samson, N. and St-Hilaire, M. and Pladys, P. and Micheau, P. and Bournival, V. and Langlois, C. and Praud, J.-P.}, title = {Effects of hypoxia and hypercapnia on nonnutritive swallowing in newborn lambs}, journal = {Journal of Applied Physiology}, year = {2007}, volume = {103}, number = {4}, pages = {1180-1188}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35349016810&doi=10.1152%2fjapplphysiol.00318.2007&partnerID=40&md5=18bc218e5c3124b9d67dd716758aa281}, doi = {https://doi.org/10.1152/japplphysiol.00318.2007} } |
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Gauthier, P.-A. and Berry, A. | Adaptive wave field synthesis for sound field reproduction: Theory, experiments, and future perspectives | 2007 | AES: Journal of the Audio Engineering Society Vol. 55(12), pp. 1107-1124 |
article | URL |
Abstract: Wave field synthesis (WFS) is a sound field reproduction technology that assumes that the reproduction environment is anechoic. A real reproduction space thus reduces the objective accuracy of WFS. Adaptive wave field synthesis (AWFS) is defined as a combination of WFS and active compensation. With AWFS the reproduction errors are minimized along with a departure penalty from the WFS solution. Analysis based on the singular value decomposition connects WFS, active compensation, and Ambisonics. The decomposition allows the practical implementation of AWFS based on independent radiation mode control. Results of experiments in different rooms support the theoretical propositions and show the efficiency of AWFS for sound field reproduction. | |||||
BibTeX:
@article{Gauthier20071107, author = {Gauthier, P.-A. and Berry, A.}, title = {Adaptive wave field synthesis for sound field reproduction: Theory, experiments, and future perspectives}, journal = {AES: Journal of the Audio Engineering Society}, year = {2007}, volume = {55}, number = {12}, pages = {1107-1124}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-38349182551&partnerID=40&md5=bacd828f03f01b4490f05ab2d502a90d} } |
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Gauthier, P.-A. and Berry, A. | Adaptive wave field synthesis for sound field reproduction: Theory, experiments and future perspectives | 2007 | Audio Engineering Society - 123rd Audio Engineering Society Convention 2007 Vol. 3, pp. 1361-1382 |
conference | URL |
Abstract: Wave field synthesis is a sound field reproduction technology which assumes that the reproduction environment is anechoic. A real reproduction space thus reduces the objective accuracy of wave field synthesis. Adaptive wave field synthesis is defined as a combination of wave field synthesis and active compensation. With adaptive wave field synthesis the reproduction errors are minimized along with the departure penalty from the wave field synthesis solution. Analysis based on the singular value decomposition connects wave field synthesis, active compensation and Ambisonics". The decomposition allows the practical implementation of adaptive wave field synthesis based on independent radiation mode control. Results of experiments in different rooms support the theoretical propositions and show the efficiency of adaptive wave field synthesis for sound field reproduction. | |||||
BibTeX:
@conference{Gauthier20071361, author = {Gauthier, P.-A. and Berry, A.}, title = {Adaptive wave field synthesis for sound field reproduction: Theory, experiments and future perspectives}, journal = {Audio Engineering Society - 123rd Audio Engineering Society Convention 2007}, year = {2007}, volume = {3}, pages = {1361-1382}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866508729&partnerID=40&md5=442835620d4b79b8428a8d6b69a3a8aa} } |
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Gauthier, P.-A. and Berry, A. | Objective evaluation of room effects on wave field synthesis | 2007 | Acta Acustica united with Acustica Vol. 93(5), pp. 824-836 |
article | URL |
Abstract: This technical paper reports the objective evaluation of sound field reproduction using wave field synthesis (WFS) in a listening room. WFS is an open-loop technology for spatial audio and it assumes a free field as the reproduction space. The main objective of this experiment was to understand how much, and how, WFS performance is reduced in-room situation in comparison with free-field situation. These undesirable effects are characterized by the coloration of the frequency response functions (FRFs) and the presence of echoes and reverberation in the reproduced impulse responses of the WFS system. This paper only addresses the objective performance (frequency response functions and wavefront shape; not the perceptual appreciation) of sound field reproduction. On that matter, this technical paper thus validates and complements other objective evaluations previously published and performed with various WFS systems in different listening rooms. A comparative review of spatial aliasing frequency definitions is also discussed in the context of sound field reproduction. © S. Hirzel Verlag - EAA. | |||||
BibTeX:
@article{Gauthier2007824, author = {Gauthier, P.-A. and Berry, A.}, title = {Objective evaluation of room effects on wave field synthesis}, journal = {Acta Acustica united with Acustica}, year = {2007}, volume = {93}, number = {5}, pages = {824-836}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35948963255&partnerID=40&md5=58c88bc8b08328eef0dd03986edaffec} } |
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Gérard, A., Berry, A. and Masson, P. | A compact active control system for tonal noise reduction in axial fans | 2007 | Noise and Vibration Worldwide Vol. 38(4), pp. 12-18 |
article | DOI URL |
Abstract: The objective of this paper is to show the feasibility of active control of tonal noise from automotive engine cooling fans using a single unbaffled loudspeaker in front of the fan. A simplified model is described for preliminary design using this configuration. A single input single output (SISO) filtered X-LMS has been implemented to control the first tones in real time. At the error microphone, the sound pressure attenuation at blade passage frequency (BPF) and its first harmonics are reduced down to the broadband noise level. At low frequency, for large sound wavelength compared to the fan radius, the sound radiation is reduced in all directions, since the dipolar directivity of the secondary noise emitted by the unbaffled loudspeaker is similar to the directivity of the primary noise emitted by the fan. | |||||
BibTeX:
@article{Gérard200712, author = {Gérard, A. and Berry, A. and Masson, P.}, title = {A compact active control system for tonal noise reduction in axial fans}, journal = {Noise and Vibration Worldwide}, year = {2007}, volume = {38}, number = {4}, pages = {12-18}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36248988616&doi=10.1260%2f095745607780886433&partnerID=40&md5=3400644ccdf8101457103cf886e18e71}, doi = {https://doi.org/10.1260/095745607780886433} } |
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Gérard, A., Berry, A., Masson, P. and Gervais, Y. | Evaluation of tonal aeroacoustic sources in subsonic fans using inverse models | 2007 | AIAA Journal Vol. 45(1), pp. 98-109 |
article | DOI URL |
Abstract: This paper aims at quantifying the most acoustically radiating modes of the blade unsteady lift and inflow velocity in the circumferential spectral domain and at localizing "hot spot" interaction areas over the fan. The proposed method is based on the inversion of the Blake model for tonal noise from subsonic fans. The unsteady lift formulation is first used to reconstruct the circumferential blade loading variations from the tonal noise radiation in free field. Then the unsteady lift is related to the inflow velocity distortions by a compressible blade response function. Discretizing the lift and velocity in the direct model leads to ill-conditioned aeroacoustic transfer matrices. The Tikhonov regularization technique is used to stabilize the inversion. The curvature of the L-curve is used to choose the regularization parameter such that the sources' strength vectors are optimally reconstructed. The singular value decomposition and the discrete Picard condition are also used to analyze the stability of the sources' reconstructions. One experimental case is considered to demonstrate the capability of the inverse model to qualitatively reconstruct the blade loading and inflow velocity variations from acoustic pressure measurements in the case of an automotive engine cooling fan. | |||||
BibTeX:
@article{Gérard200798, author = {Gérard, A. and Berry, A. and Masson, P. and Gervais, Y.}, title = {Evaluation of tonal aeroacoustic sources in subsonic fans using inverse models}, journal = {AIAA Journal}, year = {2007}, volume = {45}, number = {1}, pages = {98-109}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33846682467&doi=10.2514%2f1.21957&partnerID=40&md5=278d66957ea676350fc8176399375cea}, doi = {https://doi.org/10.2514/1.21957} } |
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Ghinet, S. and Atalla, N. | Modeling of general laminate composite structures with viscoelastic layer | 2007 | Canadian Acoustics - Acoustique Canadienne Vol. 35(3), pp. 202-203 |
article | URL |
Abstract: The modeling of a thick composite laminate plates and beams with linear viscoelastic damping is described. The problem is solved by discrete laminate method in a wave approach context. The discrete laminate approach assumes each layer described by a Reissner-Mindlin displacement field, which leads to equilibrium relations accounting for membrane, transverse shearing, bending and full inertial terms. The discrete description of each layer allows for accurate handling of thin/thick laminates and sandwich panels over the audible frequency range. The model is also applied to the calculation of the structural loss factor associated to the bending wave-type. The pure arithmetically real solution with the highest amplitude corresponds to the bending wavenumber. This solution has three asymptotical behaviors for sandwich configurations, which are pure bending at low frequencies, core's transversal shearing at mid-frequencies and pure bending of skins at high frequencies. | |||||
BibTeX:
@article{Ghinet2007202, author = {Ghinet, S. and Atalla, N.}, title = {Modeling of general laminate composite structures with viscoelastic layer}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2007}, volume = {35}, number = {3}, pages = {202-203}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35448994748&partnerID=40&md5=3b7d4fc1805307a2cb6e7b1b1dd0434d} } |
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Hamoudi, A. and Panneton, R. | Inverse acoustical characterization of porous media | 2007 | Canadian Acoustics - Acoustique Canadienne Vol. 35(3), pp. 200-201 |
article | URL |
Abstract: A six-parameter model by Johnson Lafarge is used to focus the inversion acoustical characterization of porous media. The model is used to describe the viscous and thermal dissipations of acoustic waves in the porous material. The six macroscopic parameters of the model are open porosity, static airflow resistivity, tortuosity, viscous characteristic dimension, thermal characteristic dimension, and static thermal permeability. The material can be modeled as an equivalent fluid under acoustical excitations if the frame of the porous material is assumed motionless. This equivalent fluid is described by its dynamic density and dynamic bulk modulus. Both dynamic properties are related to the macroscopic parameters of the material and depend on the frequency of excitation. | |||||
BibTeX:
@article{Hamoudi2007200, author = {Hamoudi, A. and Panneton, R.}, title = {Inverse acoustical characterization of porous media}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2007}, volume = {35}, number = {3}, pages = {200-201}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35448996042&partnerID=40&md5=da7093891e72692d4489cd8250c2eae4} } |
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Horoshenkov, K., Khan, A., Bécot, F.-X., Jaouen, L., Sgard, F., Renault, A., Amirouche, N., Pompoli, F., Prodi, N., Bonfiglio, P., Pispola, G., Asdrubali, F., Hübelt, J., Atalla, N., Amédin, C., Lauriks, W. and Boeckx, L. | Reproducibility experiments on measuring acoustical properties of rigid-frame porous media (round-robin tests) | 2007 | Journal of the Acoustical Society of America Vol. 122(1), pp. 345-353 |
article | DOI URL |
Abstract: This paper reports the results of reproducibility experiments on the interlaboratory characterization of the acoustical properties of three types of consolidated porous media: granulated porous rubber, reticulated foam, and fiberglass. The measurements are conducted in several independent laboratories in Europe and North America. The studied acoustical characteristics are the surface complex acoustic impedance at normal incidence and plane wave absorption coefficient which are determined using the standard impedance tube method. The paper provides detailed procedures related to sample preparation and installation and it discusses the dispersion in the acoustical material property observed between individual material samples and laboratories. The importance of the boundary conditions, homogeneity of the porous material structure, and stability of the adopted signal processing method are highlighted. © 2007 Acoustical Society of America. | |||||
BibTeX:
@article{Horoshenkov2007345, author = {Horoshenkov, K.V. and Khan, A. and Bécot, F.-X. and Jaouen, L. and Sgard, F. and Renault, A. and Amirouche, N. and Pompoli, F. and Prodi, N. and Bonfiglio, P. and Pispola, G. and Asdrubali, F. and Hübelt, J. and Atalla, N. and Amédin, C.K. and Lauriks, W. and Boeckx, L.}, title = {Reproducibility experiments on measuring acoustical properties of rigid-frame porous media (round-robin tests)}, journal = {Journal of the Acoustical Society of America}, year = {2007}, volume = {122}, number = {1}, pages = {345-353}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547492948&doi=10.1121%2f1.2739806&partnerID=40&md5=c60d3058b617424783ec514dfee1a73f}, doi = {https://doi.org/10.1121/1.2739806} } |
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Lemieux, R., Martin, M., Bellemare, C., Masson, P., Michaud, F., Bernard, M.-E., Fauteux, P., Julien, C., Lalonde-Filion, M., Morier, C., Morin-Guimond, A., Patry, M.-A. and Saint-Pierre, A. | Real-time coaching using robot-based semi-teleoperated cameras | 2007 | Proceedings of the 3rd IASTED International Conference on Telehealth, pp. 82-87 | conference | URL |
Abstract: To compensate for the shortage of emergency specialists and maintain quality of medical care in remote regions, this paper presents two robotic systems enabling real-time telecoaching on surgical procedures in emergency rooms. The first one uses two robotized cameras moving on rails mounted on the ceiling and perpendicular to the stretcher. Cricothyroidotomy, thoracic drain, comb tube installation, endotracheal intubation and venous access were performed and assisted by a trauma surgeon on a corpse in a controlled environment using this system. The second system increases the range of motion of one of the camera, by installing it on a two-axis rail system. This paper describes these two prototypes, the evaluation done in controlled environment, and the on-going work in improving further the robotic system. | |||||
BibTeX:
@conference{Lemieux200782, author = {Lemieux, R. and Martin, M. and Bellemare, C. and Masson, P. and Michaud, F. and Bernard, M.-E. and Fauteux, P. and Julien, C. and Lalonde-Filion, M. and Morier, C. and Morin-Guimond, A. and Patry, M.-A. and Saint-Pierre, A.}, title = {Real-time coaching using robot-based semi-teleoperated cameras}, journal = {Proceedings of the 3rd IASTED International Conference on Telehealth}, year = {2007}, pages = {82-87}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-54949094676&partnerID=40&md5=8d1d9e145e4c0f618ca4613700a8718a} } |
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Micheau, P., Louviot, R. and Berry, A. | Decentralized resonant controller for vibroacoustic active control | 2007 | 2007 Mediterranean Conference on Control and Automation, MED | conference | DOI URL |
Abstract: The problem addressed in this paper concerns the stability of decentralized resonant controller (DRC) for the disturbance rejection of a harmonic vibration disturbance. A resonant controller is presented within the formalism of the complex envelope. It is shown that the problem of stability only concerns the frequency responses at the disturbance frequency: a necessary condition of stability is to have the matrix of transfer functions Hurwitz stable at the disturbance frequency. To illustrate this condition, simulations and experimental results are presented in the case of a simply-supported panel with collocated actuator-sensor pairs. ©2007 IEEE. | |||||
BibTeX:
@conference{Micheau2007, author = {Micheau, P. and Louviot, R. and Berry, A.}, title = {Decentralized resonant controller for vibroacoustic active control}, journal = {2007 Mediterranean Conference on Control and Automation, MED}, year = {2007}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-50249113779&doi=10.1109%2fMED.2007.4433963&partnerID=40&md5=200c623998bf77839d7d8f5620751bc6}, doi = {https://doi.org/10.1109/MED.2007.4433963} } |
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Panneton, R. | Comments on the limp frame equivalent fluid model for porous media | 2007 | Journal of the Acoustical Society of America Vol. 122(6), pp. EL217-EL222 |
article | DOI URL |
Abstract: In this letter, the low and high frequency limits of the effective density characterizing a limp frame porous medium are investigated. These theoretical limits are compared to the ones found for a classical rigid frame porous medium, and to experimental measurements. While the high frequency asymptotic behaviors of both limp and rigid effective densities are usually only slightly different, their low frequency behaviors are significantly different. Compared to experimental measurements performed on a limp frame fibrous layer, only the limp frame effective density yields good correlations over the whole frequency range. © 2007 Acoustical Society of America. | |||||
BibTeX:
@article{Panneton2007, author = {Panneton, R.}, title = {Comments on the limp frame equivalent fluid model for porous media}, journal = {Journal of the Acoustical Society of America}, year = {2007}, volume = {122}, number = {6}, pages = {EL217-EL222}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-38849107002&doi=10.1121%2f1.2800895&partnerID=40&md5=c0cfde9aba235b3402d463e00509e1d4}, doi = {https://doi.org/10.1121/1.2800895} } |
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Perrot, C., Panneton, R. and Olny, X. | Computation of the dynamic thermal dissipation properties of porous media by Brownian motion simulation: Application to an open-cell aluminum foam | 2007 | Journal of Applied Physics Vol. 102(7) |
article | DOI URL |
Abstract: This paper reports simulation results of frequency dependent heat conduction through three-dimensional reconstructed unit cells of an open-cell aluminum foam under acoustic excitations. First, a three-dimensional random walk based algorithm is proposed to calculate the dynamic thermal permeability or dynamic bulk modulus of periodic complex porous geometries. Second, the error and convergence of the implemented calculation algorithm are quantified in terms of the random walk population, normalized trapping distance, and type of geometry. Finally, the algorithm is applied to the calculation of the dynamic bulk modulus of an aluminum foam and compared to laboratory measurements. Good agreement is obtained between simulations and measurements. © 2007 American Institute of Physics. | |||||
BibTeX:
@article{Perrot2007, author = {Perrot, C. and Panneton, R. and Olny, X.}, title = {Computation of the dynamic thermal dissipation properties of porous media by Brownian motion simulation: Application to an open-cell aluminum foam}, journal = {Journal of Applied Physics}, year = {2007}, volume = {102}, number = {7}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35348919439&doi=10.1063%2f1.2786899&partnerID=40&md5=35e02611f43f46af647b0e1ae47fb6de}, doi = {https://doi.org/10.1063/1.2786899} } |
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Perrot, C., Panneton, R. and Olny, X. | Periodic unit cell reconstruction of porous media: Application to open-cell aluminum foams | 2007 | Journal of Applied Physics Vol. 101(11) |
article | DOI URL |
Abstract: In this article, the issue of reconstructing an idealized periodic unit cell (PUC) to represent a porous medium is examined by means of microcomputed tomography (µCT). Using µCT, three-dimensional images of open-cell foam are collected and used to characterize the representative parameters of its cellular morphology. These parameters are used in order to reconstruct the porous medium by means of an idealized PUC: a tetrakaidecahedron with ligaments of triangular cross sections, whose characteristic dimensions have been measured on the µCT images. The proposed reconstruction of the idealized PUC is applied to four aluminum foams. The averaged macroscopic properties of the foams (open porosity and thermal characteristic length) are deduced from their respective PUC model and compared to experimental measurements and literature data. Good correlations are obtained. For each of the foams, this provides a parameterized idealized periodic unit cell on which the partial differential equations governing sound dissipation and propagation in foams can be solved with a view to studying the microphysical basis of the acoustical macrobehavior. © 2007 American Institute of Physics. | |||||
BibTeX:
@article{Perrot2007, author = {Perrot, C. and Panneton, R. and Olny, X.}, title = {Periodic unit cell reconstruction of porous media: Application to open-cell aluminum foams}, journal = {Journal of Applied Physics}, year = {2007}, volume = {101}, number = {11}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250671632&doi=10.1063%2f1.2745095&partnerID=40&md5=63f3c602c07d34c6dea75c760ff0f5e6}, doi = {https://doi.org/10.1063/1.2745095} } |
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Perrot, C., Chevillotte, F. and Panneton, R. | Symmetry of viscous permeability tensor in porous media | 2007 | Canadian Acoustics - Acoustique Canadienne Vol. 35(3), pp. 204-205 |
article | URL |
Abstract: The symmetry of the viscous permeability tensor in a porous media is analyzed. The practical importance of this property is that it can be used to assess the validity and accuracy of numerical simulations in the emerging field of bottom-up approaches for microstructure optimization of sound absorbing materials. The statistical properties of the porous frame can be defined in homogenization volumes with dimensions much smaller than the wavelength of the acoustic waves that propagate in the saturating fluid. Viscous permeability tensor is reduced to a constant diagonal element in a plane perpendicular to the axis of a porous material with hexagonal symmetry. This property can be used for error estimation of numerical computation. | |||||
BibTeX:
@article{Perrot2007204, author = {Perrot, C. and Chevillotte, F. and Panneton, R.}, title = {Symmetry of viscous permeability tensor in porous media}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2007}, volume = {35}, number = {3}, pages = {204-205}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35448975998&partnerID=40&md5=a4910bc8eb3f1f55aec0c6b7488938d9} } |
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Rhazi, D. and Atalla, N. | Modeling the vibroacoustic response of multi-materials complex structures under mechanical excitation | 2007 | Canadian Acoustics - Acoustique Canadienne Vol. 35(3), pp. 96-97 |
article | URL |
Abstract: Modeling of vibroacoustic response of multi-materials complex structure, made up of parallel and homogenous layers, under mechanical excitation is demonstrated. The first approach is based on the propagation of plane waves im the main structure and layers of the NCT, the second uses Statistical Energy Analysis (SEA) for the main structure and the layers of the NCT, while the last approach uses the model technique by calculating the equivalent impedance for the added treatment. The panel size of the aircraft is accounted for in the calculation of the acoustic indicators using the Finite Transfer Matrix Method (FEMM) and the term represents a geometrical correction to account for the finite size effect. The results show that the combination of methods can be used to eliminate the assumption of low coupling that is assumed in SEA calculations. | |||||
BibTeX:
@article{Rhazi200796, author = {Rhazi, D. and Atalla, N.}, title = {Modeling the vibroacoustic response of multi-materials complex structures under mechanical excitation}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2007}, volume = {35}, number = {3}, pages = {96-97}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35448933589&partnerID=40&md5=ee0f0660356ab477aae898db933e77d4} } |
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Richard, S. and Champoux, Y. | Evaluating the influence of damping material applied on an aluminum bike fork | 2007 | Conference Proceedings of the Society for Experimental Mechanics Series | conference | URL |
Abstract: In road cycling, several factors can influence the cyclist's comfort level: bike stability, frame compliance and geometry, material, components and accessories (wheels, fork, saddle, handlebar, etc.). A recent trend has seen the addition of damping material (elastomer capsules) on bike components such as the handlebar, saddle tube, chain stay and fork to absorb undesirable road vibrations that reduce the cyclist's comfort. The purpose of this paper is to evaluate the influence of constrained-layer damping (CLD) on an aluminum bicycle fork. Two different tests have been carried out for this study: impact hammer test on a fork in free-free boundary conditions and simulation of road impacts on a treadmill. The results of the impact hammer test show that the viscoelastic material is very effective in attenuating the fork's vibration in free-free boundary conditions. However, the effect of viscoelastic material seems to disappear when the fork is installed on the bike and subjected to road-like impacts on the treadmill. | |||||
BibTeX:
@conference{Richard2007, author = {Richard, S. and Champoux, Y.}, title = {Evaluating the influence of damping material applied on an aluminum bike fork}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2007}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861567137&partnerID=40&md5=32e54db211a6a7fed6c3ef9d7e0776b4} } |
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Robert, R., Micheau, P. and Walti, H. | A supervisor for volume-controlled tidal liquid ventilator using independent piston pumps | 2007 | Biomedical Signal Processing and Control Vol. 2(3), pp. 267-274 |
article | DOI URL |
Abstract: Liquid ventilation using perfluorochemicals (PFC) offers clear theoretical advantages over gas ventilation, such as decreased lung damage, recruitment of collapsed lung regions and lavage of inflammatory debris. This paper presents the control of a total liquid ventilator (TLV) dedicated to ventilate patients with completely filled lungs with a tidal volume of perfluorochemical liquid. The two independent piston pumps are volume controlled and pressure limited. Measurable pumping errors are corrected by a programmed supervisor module, which modifies the inserted or withdrawn volume. Pump independence also allows easy FRC modifications during ventilation. The prototype was tested on eight healthy term newborn lambs (<5 days old). © 2007. | |||||
BibTeX:
@article{Robert2007267, author = {Robert, R. and Micheau, P. and Walti, H.}, title = {A supervisor for volume-controlled tidal liquid ventilator using independent piston pumps}, journal = {Biomedical Signal Processing and Control}, year = {2007}, volume = {2}, number = {3}, pages = {267-274}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35348816203&doi=10.1016%2fj.bspc.2007.07.010&partnerID=40&md5=43c8e3e1f2bde5bbecb0f46e9236f52b}, doi = {https://doi.org/10.1016/j.bspc.2007.07.010} } |
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Salissou, Y. and Panneton, R. | Pressure/mass method to measure open porosity of porous solids | 2007 | Journal of Applied Physics Vol. 101(12) |
article | DOI URL |
Abstract: This work presents a method to directly determine the open porosity of porous solids, and more particularly those used in sound absorbing liners. The method is based on the measurement of four masses at four static pressures from which the open porosity and true mass density are deduced using the perfect gas law. The precision of the method in relation with the used experimental setup is studied, and a simple expression is derived to predict the experimental error in function of the bulk volume of the sample to test. For a given experimental setup, this simple expression can be used to select the amount of bulk volume to test to reach a given precision. The method and its error prediction are tested experimentally on different samples of theoretically known open porosity. Good correlations are obtained for low and high porosity samples. © 2007 American Institute of Physics. | |||||
BibTeX:
@article{Salissou2007, author = {Salissou, Y. and Panneton, R.}, title = {Pressure/mass method to measure open porosity of porous solids}, journal = {Journal of Applied Physics}, year = {2007}, volume = {101}, number = {12}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547375326&doi=10.1063%2f1.2749486&partnerID=40&md5=b9e65f43f1c12bae2e1e52b6a4151e5b}, doi = {https://doi.org/10.1063/1.2749486} } |
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Salissou, Y. and Panneton, R. | An index of heterogeneity of sound absorbing porous materials | 2007 | Canadian Acoustics - Acoustique Canadienne Vol. 35(3), pp. 196-197 |
article | URL |
Abstract: An Index of heterogeneity, through-thickness homogeneity (TTH), of sound absorbing porous materials is calculated. The calculation of this TTH index only requires impedance tube measurements of the acoustical surface impedance on both faces of the tested material. A two-layer rigid frame porous system representing a single porous layer with a sudden change in its physical properties is studied to verify the validity of this TTH index. The sound absorption coefficient, complex wave number, and characteristic impedance of this equivalent single layer are computed in the normal and inverted positions. The heterogeneity of a material can be quantified by the average relative standard deviation (ARSD) of a bulk property measured respectively in both normal and inverted configurations. The ARSD of the three latter bulk properties are computed to identify the most sensitive bulk property to TTH. | |||||
BibTeX:
@article{Salissou2007196, author = {Salissou, Y. and Panneton, R.}, title = {An index of heterogeneity of sound absorbing porous materials}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2007}, volume = {35}, number = {3}, pages = {196-197}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35448981820&partnerID=40&md5=a568fb82d45e4b528474a4d44fed6916} } |
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Serry Ahmed, M., Kim, S., Park, C. and Atalla, N. | Production of novel sound absorption microcellular foams using high internal phase emulsion polymerization | 2007 | Annual Technical Conference - ANTEC, Conference Proceedings Vol. 3, pp. 1491-1496 |
conference | URL |
Abstract: High internal phase emulsion (HIPE) polymerization foaming process is controlled for production of novel foams with various microcellular structures and morphologies. The objective is to produce lighter weight sound insulation packages with superior acoustical performance for passive noise control in automotive structures using microcellular foams. This was achieved through the control of the foaming process for production of variable microcellular structures and morphologies for the novel foams under investigation. As an attempt to reduce the cell size and increase microcellular density and open cell content without sacrificing the mechanical prosperities, the microcellular foams combining viscosity improvers into the conventional formulation of styrene and water system were prepared via high internal phase emulsion polymerization. | |||||
BibTeX:
@conference{SerryAhmed20071491, author = {Serry Ahmed, M.Y. and Kim, S.G. and Park, C.B. and Atalla, N.}, title = {Production of novel sound absorption microcellular foams using high internal phase emulsion polymerization}, journal = {Annual Technical Conference - ANTEC, Conference Proceedings}, year = {2007}, volume = {3}, pages = {1491-1496}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34648847028&partnerID=40&md5=fa8674f4788c725b721dec9328dd23ec} } |
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Serry Ahmed, M., Kim, S., Atalla, N., Park, C. and Lee, S. | Production of novel sound absorption microcellular foams using high internal phase emulsion polymerization | 2007 | Annual Technical Conference - ANTEC, Conference Proceedings Vol. 3, pp. 1497-1502 |
conference | URL |
Abstract: High internal phase emulsion (HIPE) polymerization foaming process is controlled for production of novel foams with various microcellular structures and morphologies. The objective is to produce lighter weight sound insulation packages with superior acoustical performance for passive noise control in automotive structures using microcellular foams. This was achieved through the control of the foaming process for production of variable microcellular structures and morphologies for the novel foams under investigation. As an attempt to reduce the cell size and increase the microcellular density and the open cell content without sacrificing the mechanical properties, microcellular foams combining viscosity improvers into the conventional formulation of styrene and water system were prepared via high internal phase emulsion polymerization. | |||||
BibTeX:
@conference{SerryAhmed20071497, author = {Serry Ahmed, M.Y. and Kim, S.G. and Atalla, N. and Park, C.B. and Lee, S.J.}, title = {Production of novel sound absorption microcellular foams using high internal phase emulsion polymerization}, journal = {Annual Technical Conference - ANTEC, Conference Proceedings}, year = {2007}, volume = {3}, pages = {1497-1502}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34648823713&partnerID=40&md5=fd214a36579711555c9b10e234843298} } |
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Sgard, F., Atalla, N. and Amedin, C. | Vibro-acoustic behavior of a cavity backed by a plate coated with a meso-heterogeneous porous material | 2007 | Acta Acustica united with Acustica Vol. 93(1), pp. 106-114 |
article | URL |
Abstract: The acoustic absorption performance of heterogeneous materials made up from a combination of thin porous patches, with different acoustic properties has been investigated recently by the authors. It has been shown that absorption could be significantly increased in the case of properly designed macroperforated wools in a large frequency band. This paper concentrates on the damping induced by a porous material containing embedded meso-heterogeneities. This meso-heterogeneous porous material is made up of a porous substrate containing solid inclusions or air cavities. It is attached to the inner face of a panel radiating inside a cavity. The panel is either excited mechanically or acoustically using an oblique incidence plane wave. The numerical model is based on a finite element formulation for the different material components. The coupling between the inclusions (solid or acoustic) and the porous patches is accounted for naturally through the use of an appropriate mixed pressure-displacement formulation of Biot's poroelasticity equations. Numerical and experimental results are presented to show the influence of heterogeneities on the damping in the system. © S. Hirzel Verlag EAA. | |||||
BibTeX:
@article{Sgard2007106, author = {Sgard, F.C. and Atalla, N. and Amedin, C.K.}, title = {Vibro-acoustic behavior of a cavity backed by a plate coated with a meso-heterogeneous porous material}, journal = {Acta Acustica united with Acustica}, year = {2007}, volume = {93}, number = {1}, pages = {106-114}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33847104643&partnerID=40&md5=8c78bb23a856ea0c21704612e8bfcec7} } |
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Sgard, F., Nelisse, H. and Atalla, N. | Modeling of the sound transmission loss of leaks and openings | 2007 | 14th International Congress on Sound and Vibration 2007, ICSV 2007 Vol. 1, pp. 156-163 |
conference | URL |
Abstract: The airborne sound transmission performance of structures may be strongly affected by the presence of apertures. These apertures might be designed on purpose to allow for the circulation of matter (machinery enclosures) or for the passage of wires and pipes through the structure (vehicles, buildings). They are then referred to as openings. They could also be unwanted or not part of the initial design due to bad assembly and/or mounting conditions. They are then called leaks. These two kinds of apertures differ by their size relative to the acoustic wavelength. To predict the insulating performance of a structure involving apertures, it is often required to know the oblique incidence or diffuse field sound transmission loss (TL) of the aperture. Numerous models exist for the normal incidence TL but rigorous models for oblique incidence and diffuse field excitations have rarely been considered. The diffuse field TL is usually obtained using a correction factor applied to the normal incidence TL which ranges from Odb to 5dB depending on the authors. The purpose of this paper is to propose a general efficient model based on the description of the field inside the aperture in terms of propagating and evanescent acoustic modes together with an efficient computation of modal radiation impedance matrices to predict the oblique incidence and diffuse field TL of rectangular and circular apertures of finite depth. The model is validated by comparison with existing experimental data and models. Numerical results illustrating the normal incidence, oblique incidence and diffuse field TL of apertures are then provided and the relationships between these indicators are discussed. | |||||
BibTeX:
@conference{Sgard2007156, author = {Sgard, F. and Nelisse, H. and Atalla, N.}, title = {Modeling of the sound transmission loss of leaks and openings}, journal = {14th International Congress on Sound and Vibration 2007, ICSV 2007}, year = {2007}, volume = {1}, pages = {156-163}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881455850&partnerID=40&md5=290f92b3c2ebbb43960ca90506c39b98} } |
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Sgard, F., Nelisse, H. and Atalla, N. | On the modeling of the diffuse field sound transmission loss of finite thickness apertures | 2007 | Journal of the Acoustical Society of America Vol. 122(1), pp. 302-313 |
article | DOI URL |
Abstract: The modeling of the diffuse field sound transmission loss (TL) of apertures has been rarely considered in the literature. The aims of this paper are (i) to give a comprehensive review of the existing models, (ii) to propose a general efficient and rigorous numerical method to predict the diffuse field TL of apertures of rectangular and circular cross section, (iii) to provide the reader with numerical results regarding this indicator together with its relation with the normal incidence case for various geometrical configurations, and (iv) to conclude on the relevance of using such a sophisticated model compared to more classical normal incidence ones. The proposed approach is based on the description of the sound field inside the aperture in terms of propagating and evanescent acoustic modes. The radiation of the aperture is accounted for using a modal radiation impedance matrix. The coupled problem is solved in terms of modal contribution factors. The convergence of the approach is then investigated and the model is validated by comparisons with existing models for various configurations and excitations. Several numerical examples are provided regarding the normal incidence and diffuse field TL for various apertures and the relationship between these two indicators is discussed. © 2007 Acoustical Society of America. | |||||
BibTeX:
@article{Sgard2007302, author = {Sgard, F. and Nelisse, H. and Atalla, N.}, title = {On the modeling of the diffuse field sound transmission loss of finite thickness apertures}, journal = {Journal of the Acoustical Society of America}, year = {2007}, volume = {122}, number = {1}, pages = {302-313}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547482624&doi=10.1121%2f1.2735109&partnerID=40&md5=b30738d62d7ea5e22a9e0a7e958e2e87}, doi = {https://doi.org/10.1121/1.2735109} } |
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St-Hilaire, M., Samson, N., Nsegbe, E., Duvareille, C., Moreau-Bussière, F., Micheau, P., Lebon, J. and Praud, J.-P. | Postnatal maturation of laryngeal chemoreflexes in the preterm lamb | 2007 | Journal of Applied Physiology Vol. 102(4), pp. 1429-1438 |
article | DOI URL |
Abstract: Laryngeal chemoreflexes (LCR) are triggered by the contact of liquids with the laryngeal mucosa. In the mature organism, LCR trigger lower airway protective responses (coughing, effective swallowing, and arousal) to prevent aspiration. General belief holds that LCR are responsible for apnea and bradycardia in the newborn mammal, including humans. Our laboratory has recently shown that LCR in full-term lambs are consistently analogous to the mature LCR reported in adult mammals, without significant apneas and bradycardias (St-Hilaire M, Nsegbe E, Gagnon-Gervais K, Samson N, Moreau-Bussiere F, Fortier PH, and Praud J-P. J Appl Physiol 98: 2197-2203, 2005). The aim of the present study was to assess LCR in nonsedated, newborn preterm lambs born at 132 days of gestation (term = 147 days). The preterm lambs were instrumented for recording glottal adductor electromyogram, electroencephalogram, eye movements, heart rate, respiration, and oximetry. A chronic supraglottal catheter was used for injecting 0.5 ml of saline, distilled water, and HCl (pH 2) during quiet sleep, active sleep, and wakefulness on postnatal days 7 (D7) and 14 (D14). Laryngeal stimulation by water or HCl on D7 induced significant apneas, bradycardia, and desaturation, which, at times, appeared potentially life-threatening. No significant apneas, bradycardias, or desaturation were observed on D14. No consistent effects of sleep state could be shown in the present study. In conclusion, laryngeal stimulation by liquids triggers potentially dangerous LCR in preterm lambs on D7, but not on D14. It is proposed that maturation of the LCR between D7 and D14 is partly involved in the disappearance of apneas/bradycardias of prematurity with postnatal age. Copyright © 2007 by the American Physiological Society. | |||||
BibTeX:
@article{St-Hilaire20071429, author = {St-Hilaire, M. and Samson, N. and Nsegbe, E. and Duvareille, C. and Moreau-Bussière, F. and Micheau, P. and Lebon, J. and Praud, J.-P.}, title = {Postnatal maturation of laryngeal chemoreflexes in the preterm lamb}, journal = {Journal of Applied Physiology}, year = {2007}, volume = {102}, number = {4}, pages = {1429-1438}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34147154942&doi=10.1152%2fjapplphysiol.00977.2006&partnerID=40&md5=1c73d464bba84dc062209de4196932ea}, doi = {https://doi.org/10.1152/japplphysiol.00977.2006} } |
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Touchais, A., Atalla, N. and Panneton, R. | A new non-linear impedance model for liners | 2007 | Canadian Acoustics - Acoustique Canadienne Vol. 35(3), pp. 98-99 |
article | URL |
Abstract: A non-linear impedance model for linear part, the proposed non-linear resistance, and frequency shift effects is presented that allows simulations of various perforated plate configurations. The model considers only the effects of resonator geometry and incident sound pressure amplitude according to frequency. The perforated plate used in the experiment has a perforation diameter of 1mm, porosity of 4.5%, a thickness of 2mm, and a cavity depth of 25mm. It was seen that the absorption's maxima increases with SPL and shifts towards high frequency. The radius and thickness of the perforations are modified as a function of the acoustical Mach number. The results show that the effective radius and thickness if the perforations decrease at high SPL and the corrections are added to the Ma's model for the linear component of the impedance and Melling's model for the nonlinear effects on the resistance. | |||||
BibTeX:
@article{Touchais200798, author = {Touchais, A. and Atalla, N. and Panneton, R.}, title = {A new non-linear impedance model for liners}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2007}, volume = {35}, number = {3}, pages = {98-99}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35448996890&partnerID=40&md5=6eefb1682e5a8aecd6a433acbfe1ab5c} } |
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Yettou, E.-M., Desrochers, A. and Champoux, Y. | A new analytical model for pressure estimation of symmetrical water impact of a rigid wedge at variable velocities | 2007 | Journal of Fluids and Structures Vol. 23(3), pp. 501-522 |
article | DOI URL |
Abstract: In this paper we present an analytical solution to symmetrical water impact problems of a two-dimensional wedge. Unlike previous studies, we have taken into account the effect of velocity reduction of the solid body upon impact in order to determine impact pressure as well as the overall force acting on the body. This feature of our study provides a better estimate of the transitory nature of the phenomenon and leads to a more precise evaluation of the true dynamic load borne by the body. We obtained the solution to this problem through a generalization of the Wagner formulation and the use of an existing analytical prediction model of the entry velocity of the wedge. This approach allows us to obtain an original analytical equation for pressure in terms of the kinetics and geometrical parameters of the impact. The validity of the proposed model is demonstrated by a favourable comparison between the analytical results and the physical experiments carried out on several wedge models. © 2006 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Yettou2007501, author = {Yettou, E.-M. and Desrochers, A. and Champoux, Y.}, title = {A new analytical model for pressure estimation of symmetrical water impact of a rigid wedge at variable velocities}, journal = {Journal of Fluids and Structures}, year = {2007}, volume = {23}, number = {3}, pages = {501-522}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34047129616&doi=10.1016%2fj.jfluidstructs.2006.10.001&partnerID=40&md5=2e25bc97bc83419f06966df3e7db1f47}, doi = {https://doi.org/10.1016/j.jfluidstructs.2006.10.001} } |
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Ahmed, M., Lee, P., Park, C. and Atalla, N. | Application of novel viscoelastic microcellular foams for passive noise control in automotive body structures | 2006 | SAE Technical Papers | article | DOI URL |
Abstract: This paper discusses the development of lighter weight, superior acoustic performance and cost effective viscoelastic microcellular foams for the use in automotive passive noise control panels. The study incorporates the control of the foaming process for production of variable microcellular structures and morphologies for the novel foams under investigation. For that purpose, the foaming process was controlled for production of foam samples with various microcellular structures. Cross linked LDPE was used as a base material for the produced foams. Very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9E108 - 1.6E109 cells/cm3) and desired expansion ratios (3 - 9 folds) were successfully obtained. While the material is overly porous, it is noted that the unfoamed skins on the outer surfaces of the samples have prevented sound waves from penetrating the samples. Manual skin removal resulted in slight improvement in sound absorption testing. However, in order to get more reliable data, skinless samples need to be produced. Copyright © 2006 SAE International. | |||||
BibTeX:
@article{Ahmed2006, author = {Ahmed, M.Y.S. and Lee, P.C. and Park, C.B. and Atalla, N.}, title = {Application of novel viscoelastic microcellular foams for passive noise control in automotive body structures}, journal = {SAE Technical Papers}, year = {2006}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877436170&doi=10.4271%2f2006-01-0707&partnerID=40&md5=d54f5e42d3c57b62bf5bd2b98f9f28d3}, doi = {https://doi.org/10.4271/2006-01-0707} } |
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Ahmed, M., Lee, P., Park, C. and Atalla, N. | Microcellular open-cell foams for noise control in automotive body structures | 2006 | Annual Technical Conference - ANTEC, Conference Proceedings Vol. 1, pp. 27-31 |
conference | URL |
Abstract: Foaming process is controlled for production of novel foams with various microcellular structures and morphologies. The objective is to produce lighter weight sound insulation packages with superior acoustical performance for passive noise control in automotive structures using microcellular foams. This was achieved through the control of the foaming process for production of variable microcellular structures and morphologies for the novel foams under investigation. | |||||
BibTeX:
@conference{Ahmed200627, author = {Ahmed, M.Y.S. and Lee, P.C. and Park, C.B. and Atalla, N.}, title = {Microcellular open-cell foams for noise control in automotive body structures}, journal = {Annual Technical Conference - ANTEC, Conference Proceedings}, year = {2006}, volume = {1}, pages = {27-31}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745592224&partnerID=40&md5=f967e29aa3fe3e64fcfe5695f2775380} } |
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Ahmed, M., Park, C. and Atalla, N. | Control of the structure and morphology for production of novel LDPE acoustical foams | 2006 | Cellular Polymers Vol. 25(5), pp. 277-292 |
article | URL |
Abstract: This paper discusses the control of the foaming process for production of variable microcellular structures and morphologies for novel acoustical foams under investigation. For that purpose, the foaming process was controlled for production of foam samples with various microcellular structures. Crosslinked LDPE was used as a base material for the produced foams. Very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9×10 3 - 1.6×10 9 cells/cm 3) and desired expansion ratios (3 - 9 folds) were successfully obtained. While the material is overly porous, it is noted that the unfoamed skins on the outer surfaces of the samples have prevented sound waves from penetrating the samples. Manual skin removal resulted in slight improvement in sound absorption testing. However, in order to get more reliable data, skinless samples need to be produced. © Rapra Technology, 2006. | |||||
BibTeX:
@article{Ahmed2006277, author = {Ahmed, M.Y.S. and Park, C.B. and Atalla, N.}, title = {Control of the structure and morphology for production of novel LDPE acoustical foams}, journal = {Cellular Polymers}, year = {2006}, volume = {25}, number = {5}, pages = {277-292}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33751584087&partnerID=40&md5=e48e6c1ab9c63dbc4c11f6c2718d97d8} } |
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Atalla, Y., Atalla, N., Fu, J. and Naguib, H. | The effect of processing parameters on the acoustical efficiency of open-cell PMMA materials | 2006 | SAE Technical Papers | article | DOI URL |
Abstract: Porous materials are widely used for noise control in the automotive industry. However, due to the weight and space saving considerations, the use of bulky thicknesses of these materials is limited in industrial applications, thus reducing the effectiveness of the acoustic treatment. Consequently, thinner materials with improved acoustic properties are required to achieve a satisfactory noise reduction. One of the promising methods to enhance the acoustic performance of a porous material is the optimization of its macroscopic acoustic parameters through inner micro-structure properties control. Thematically, it is of interest to understand and link material inner micro-structure such as cell size, cell distribution, etc. to main macroscopic parameters which control the sound absorption of a material such as porosity, flow resistance, etc. This study presents a new processing technology to manufacture open-cell PMMA materials using a gas foaming/particulate leaching method and a constrained foam molding process. A parametric study is conducted by altering the processing parameters such as foaming temperature, size and percentage of foaming agent which affect the cell morphologies and control the macroscopic properties. The acoustic performance is controlled by adjusting the processing parameters with respect to the inner structure of the material. The correlations between the resulting cell morphologies and sound absorption effectiveness are investigated. The results conclude that understanding and controlling the porous material inner structure through adjusting the processing parameters are crucial for the development of porous materials with optimized acoustical efficiency. Copyright © 2006 SAE International. | |||||
BibTeX:
@article{Atalla2006, author = {Atalla, Y. and Atalla, N. and Fu, J. and Naguib, H.E.}, title = {The effect of processing parameters on the acoustical efficiency of open-cell PMMA materials}, journal = {SAE Technical Papers}, year = {2006}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877415199&doi=10.4271%2f2006-01-0711&partnerID=40&md5=5e0393bacdd45543c325ebb8c19ed9e3}, doi = {https://doi.org/10.4271/2006-01-0711} } |
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Atalla, N., Sgard, F. and Amedin, C. | On the modeling of sound radiation from poroelastic materials | 2006 | Journal of the Acoustical Society of America Vol. 120(4), pp. 1990-1995 |
article | DOI URL |
Abstract: Numerical approaches based on finite element discretizations of Biot's poroelasticity equations provide efficient tools to solve problems where the porous material is coupled to elastic structures and finite extent acoustic cavities. Sometimes, it may be relevant to evaluate the radiation of a poroelastic material into an infinite fluid medium. Examples include (i) the evaluation of the diffuse field sound absorption coefficient of a porous material and/or the sound transmission loss of an elastic plate coupled to a porous sheet, (ii) the assessment of the acoustic radiation damping of a porous material coupled to a vibrating structure. The latter is particularly important for the correct experimental characterization of the intrinsic damping of the material's frame. Up to now, the acoustic radiation of a porous medium into an unbounded fluid medium has usually been neglected. The classical approaches for modeling free field radiation of porous materials (i) assumes the interstitial pressure at the radiation surface to be zero or (ii) fixes the radiation impedance to an approximate value. This paper discusses the limitations of these assumptions and presents a numerical formulation for evaluating the sound radiation of baffled poroelastic media including fluid loading effects. The problem is solved using a mixed FEM-BEM approach where the fluid loading is accounted for using an admittance matrix. Both numerical examples and a transmission loss test are presented to illustrate the performance of the technique and its applications. © 2006 Acoustical Society of America. | |||||
BibTeX:
@article{Atalla20061990, author = {Atalla, N. and Sgard, F. and Amedin, C.K.}, title = {On the modeling of sound radiation from poroelastic materials}, journal = {Journal of the Acoustical Society of America}, year = {2006}, volume = {120}, number = {4}, pages = {1990-1995}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749574580&doi=10.1121%2f1.2261244&partnerID=40&md5=3e18f4a9d1678dee8c68be4ddade0fda}, doi = {https://doi.org/10.1121/1.2261244} } |
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Baudry, M., Micheau, P. and Berry, A. | Decentralized harmonic active vibration control of a flexible plate using piezoelectric actuator-sensor pairs | 2006 | Journal of the Acoustical Society of America Vol. 119(1), pp. 262-277 |
article | DOI URL |
Abstract: We have investigated decentralized active control of periodic panel vibration using multiple pairs combining PZT actuators and PVDF sensors distributed on the panel. By contrast with centralized MIMO controllers used to actively control the vibrations or the sound radiation of extended structures, decentralized control using independent local control loops only requires identification of the diagonal terms in the plant matrix. However, it is difficult to a priori predict the global stability of such decentralized control. In this study, the general situation of noncollocated actuator-sensor pairs was considered. Frequency domain gradient and Newton-Raphson adaptation of decentralized control were analyzed, both in terms of performance and stability conditions. The stability conditions are especially derived in terms of the adaptation coefficient and a control effort weighting coefficient. Simulations and experimental results are presented in the case of a simply supported panel with four PZT-PVDF pairs distributed on it. Decentralized vibration control is shown to be highly dependent on the frequency, but can be as effective as a fully centralized control even when the plant matrix is not diagonal-dominant or is not strictly positive real (not dissipative). © 2006 Acoustical Society of America. | |||||
BibTeX:
@article{Baudry2006262, author = {Baudry, M. and Micheau, P. and Berry, A.}, title = {Decentralized harmonic active vibration control of a flexible plate using piezoelectric actuator-sensor pairs}, journal = {Journal of the Acoustical Society of America}, year = {2006}, volume = {119}, number = {1}, pages = {262-277}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-30844450358&doi=10.1121%2f1.2139624&partnerID=40&md5=b169a84487e06a6a67b5978fdb7088d5}, doi = {https://doi.org/10.1121/1.2139624} } |
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Bélanger, P., Berry, A., Pasco, Y., St-Amant, Y. and Rajan, S. | Active structural acoustic control of a bell 407 transmission noise | 2006 | Annual Forum Proceedings - AHS International Vol. I, pp. 1-10 |
conference | URL |
Abstract: The aim of this research project is to evaluate the feasibility and effectiveness, under controlled conditions, of active structural acoustic control of a Bell 407 transmission on a laboratory set-up in order to attenuate the vibration of the receiving roof panel and its sound radiation, in the 500-3000 Hz range. The Bell 407 transmission has 2 stages, a bevel gear and a planetary gear train. The planetary gear train theory and the order tracking analysis are used to evaluate the frequencies generated by the transmission. For the active control experiments, a laboratory set-up is designed with an actual helicopter transmission, an aluminium plate representative of the rigidity of the helicopter roof and a rigid acoustic cavity. A finite element model of the laboratory installation is developed, in order to investigate several active vibration control strategies. Various piezoceramic actuator and structural sensor arrangements were simulated with an optimal active control algorithm. The best configuration was obtained when the control actuators are mounted on the transmission struts. In order to decrease the control effort as much as possible without degrading the control performance, a Principal Component analysis of the secondary path transfer matrix was investigated with promising results. © 2006 by the American Helicopter Society International, Inc. | |||||
BibTeX:
@conference{Bélanger20061, author = {Bélanger, P. and Berry, A. and Pasco, Y. and St-Amant, Y. and Rajan, S.}, title = {Active structural acoustic control of a bell 407 transmission noise}, journal = {Annual Forum Proceedings - AHS International}, year = {2006}, volume = {I}, pages = {1-10}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884322533&partnerID=40&md5=a8f6819c782c42b99975cf3311fbd55e} } |
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Bélanger, P., Berry, A., Pasco, Y., St-Amant, Y. and Rajan, S. | Active structural acoustic control of a Bell 407 transmission noise | 2006 | Annual Forum Proceedings - AHS International Vol. II, pp. 788-797 |
conference | URL |
Abstract: The aim of this research project is to evaluate the feasibility and effectiveness, under controlled conditions, of active structural acoustic control of a Bell 407 transmission on a laboratory set-up in order to attenuate the vibration of the receiving roof panel and its sound radiation, in the 500-3000 Hz range. The Bell 407 transmission has 2 stages, a bevel gear and a planetary gear train. The planetary gear train theory and the order tracking analysis are used to evaluate the frequencies generated by the transmission. For the active control experiments, a laboratory set-up is designed with an actual helicopter transmission, an aluminium plate representative of the rigidity of the helicopter roof and a rigid acoustic cavity. A finite element model of the laboratory installation is developed, in order to investigate several active vibration control strategies. Various piezoceramic actuator and structural sensor arrangements were simulated with an optimal active control algorithm. The best configuration was obtained when the control actuators are mounted on the transmission struts. In order to decrease the control effort as much as possible without degrading the control performance, a Principal Component analysis of the secondary path transfer matrix was investigated with promising results. Copyright © 2006 by the American Helicopter Society International, Inc. All right reserved. | |||||
BibTeX:
@conference{Bélanger2006788, author = {Bélanger, P. and Berry, A. and Pasco, Y. and St-Amant, Y. and Rajan, S.}, title = {Active structural acoustic control of a Bell 407 transmission noise}, journal = {Annual Forum Proceedings - AHS International}, year = {2006}, volume = {II}, pages = {788-797}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748444534&partnerID=40&md5=bebf70584d68d2797b9279a39faa9a2f} } |
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Cotoni, V., Masson, P. and Ccté, F. | A finite element for piezoelectric multilayered plates: Combined higher-order and piecewise linear C0 formulation | 2006 | Journal of Intelligent Material Systems and Structures Vol. 17(2), pp. 155-166 |
article | DOI URL |
Abstract: A finite element is presented for the static and dynamic analysis of smart multilayered plates. A fourth-order expansion is combined with a piecewise linear term to describe the distribution of the in-plane displacements through the thickness. The out-of-plane displacement is assumed constant through the thickness. Both free edges and interlaminar continuity conditions are satisfied, thus reducing the number of elastic unknowns to nine whatever be the number of layers. To this aim, two redundant unknowns describing the two derivatives of the out-of-plane displacement with respect to the in-plane coordinates are introduced and related to the out-of-plane displacement by the use of penalty functions. A quadratic distribution of the electric potential is used inside each piezoelectric layer to completely account for the piezoelectric coupling effects. © 2006 SAGE Publications. | |||||
BibTeX:
@article{Cotoni2006155, author = {Cotoni, V. and Masson, P. and Ccté, F.}, title = {A finite element for piezoelectric multilayered plates: Combined higher-order and piecewise linear C0 formulation}, journal = {Journal of Intelligent Material Systems and Structures}, year = {2006}, volume = {17}, number = {2}, pages = {155-166}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-32944462230&doi=10.1177%2f1045389X06056501&partnerID=40&md5=51851d7d82872f7b5115c284eae1c269}, doi = {https://doi.org/10.1177/1045389X06056501} } |
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Douville, H., Masson, P. and Berry, A. | On-resonance transmissibility methodology for quantifying the structure-borne road noise of an automotive suspension assembly | 2006 | Applied Acoustics Vol. 67(4), pp. 358-382 |
article | DOI URL |
Abstract: In this paper, a methodology is presented for the analysis of the structure-borne noise transmission paths for an automotive suspension assembly. First, a fully-instrumented test bench consisting of a wheel/suspension/lower suspension A-arm assembly was designed in order to identify the vibro-acoustic transmission paths (up to 250 Hz) for white noise excitation of the wheel. Second, frequency response function measurements between the excitation signal and each suspension/chassis linkages are used to characterize the different transmission paths that transmit energy through the chassis of the car. Finally, a synthesis of the major resonances of the suspension is drawn, with the objective of indicating which suspension transfer paths contribute the most to the structural forces transmitted to the chassis. On-resonance force transmissibility factors (ORTF) were calculated to provide an overall classification of the system resonances to the vibration transmission through the individual suspension linkages and in all axes. © 2005 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Douville2006358, author = {Douville, H. and Masson, P. and Berry, A.}, title = {On-resonance transmissibility methodology for quantifying the structure-borne road noise of an automotive suspension assembly}, journal = {Applied Acoustics}, year = {2006}, volume = {67}, number = {4}, pages = {358-382}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-29244479488&doi=10.1016%2fj.apacoust.2005.07.002&partnerID=40&md5=210579b34c72069382faac83f14d9fc7}, doi = {https://doi.org/10.1016/j.apacoust.2005.07.002} } |
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Fauteux, P., Micheau, P. and Bourassa, P. | Time-scaling control of a compass type biped robot | 2006 | Proceedings of the 8th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2005, pp. 277-284 | conference | DOI URL |
Abstract: This paper presents a robust control strategy driving an actuated compass gait robot towards steady gaits. The originality lies in the generation of the swing leg references as a simple function of the supporting leg angle. Simulations and experimentation showed that the system exhibits asymptotically stable walking cycles with large and strong basins of attraction. © 2006 Springer-Verlag Berlin Heidelberg. | |||||
BibTeX:
@conference{Fauteux2006277, author = {Fauteux, P. and Micheau, P. and Bourassa, P.}, title = {Time-scaling control of a compass type biped robot}, journal = {Proceedings of the 8th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2005}, year = {2006}, pages = {277-284}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881135270&doi=10.1007%2f3-540-26415-9-33&partnerID=40&md5=5f08318d9dd0230d0555aa6af7414561}, doi = {https://doi.org/10.1007/3-540-26415-9-33} } |
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Gauthier, P.-A. and Berry, A. | Adaptive wave field synthesis with independent radiation mode control for active sound field reproduction: Theory | 2006 | Journal of the Acoustical Society of America Vol. 119(5), pp. 2721-2737 |
article | DOI URL |
Abstract: Sound field reproduction finds applications in music or audio reproduction and experimental acoustics. For audio applications, sound field reproduction can be used to artificially reproduce the spatial character of natural hearing. The general objective is then to reproduce a sound field in a real reproduction environment. Wave field synthesis (WFS) is a known open-loop technology which assumes that the reproduction environment is anechoic. For classical WFS, the room response thus reduces the quality of the physical sound field reproduction. In this paper, adaptive wave field synthesis (AWFS) is analytically investigated as an adaptive sound field reproduction system combining WFS and active control with a limited number of reproduction error sensors to compensate the response of the listening environment. The primary point of this paper is the definition of AWFS. Therefore, the fundamental behavior of AWFS is illustrated by analytical considerations and simple free-field simulation results. As demonstrated, AWFS is fundamentally related to WFS and "Ambisonics." The paper introduces independent adaptive control of sound field reproduction on the basis of radiation modes, via the singular value decomposition of the transfer impedance matrix. Possible practical independent control of radiation modes for AWFS is discussed. © 2006 Acoustical Society of America. | |||||
BibTeX:
@article{Gauthier20062721, author = {Gauthier, P.-A. and Berry, A.}, title = {Adaptive wave field synthesis with independent radiation mode control for active sound field reproduction: Theory}, journal = {Journal of the Acoustical Society of America}, year = {2006}, volume = {119}, number = {5}, pages = {2721-2737}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646461135&doi=10.1121%2f1.2186514&partnerID=40&md5=a1818dc45437b2d37d82462fe7d4502a}, doi = {https://doi.org/10.1121/1.2186514} } |
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Ghinet, S. and Atalla, N. | Vibro-acoustic behaviors of flat sandwich composite panels | 2006 | Transactions of the Canadian Society for Mechanical Engineering Vol. 30(4), pp. 473-493 |
article | URL |
Abstract: The main objective of this paper is to present a theoretical approach to model the vibro-acoustic behavior of flat sandwich composite panels. Two models are studied: symmetrical laminate composite and sandwich composite panel. The theories are developed in a wave approach context. It is shown that a discrete layers sandwich composite panel modeling type leads to a 12th order relation of dispersion while a laminate composite panel modeling leads to a 6th order relation of dispersion. The two models give similar results at low frequencies but the modeling of a sandwich panel using the laminate panel theory leads to inaccuracies at high frequencies. The dispersion relations are first solved in the context of generalized polynomial complex eigenvalues problems. Next, the dispersion relations are used to derive the analytical expression of the critical frequencies and to calculate the natural frequencies of the panel. Using the dispersion relation's solutions, the study is then focused on the numerical computation of the group velocity, the modal density and the total transmission loss. | |||||
BibTeX:
@article{Ghinet2006473, author = {Ghinet, S. and Atalla, N.}, title = {Vibro-acoustic behaviors of flat sandwich composite panels}, journal = {Transactions of the Canadian Society for Mechanical Engineering}, year = {2006}, volume = {30}, number = {4}, pages = {473-493}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250877011&partnerID=40&md5=2926c3fe5579a9430b9b76b00b7f702a} } |
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Ghinet, S., Atalla, N. and Osman, H. | Diffuse field transmission into infinite sandwich composite and laminate composite cylinders | 2006 | Journal of Sound and Vibration Vol. 289(4-5), pp. 745-778 |
article | DOI URL |
Abstract: This paper is concerned with the modelling of diffuse field transmission into composite laminate and sandwich composite infinite cylinders. Two models are presented and compared: Symmetrical Laminate composite and discrete thick laminate composite. The latter is shown to handle accurately, as a particular case, the first model, and the important case of sandwich composite shells. In both models, membrane, bending, transverse shearing as well as rotational inertia effects and orthotropic ply angle of the layers are considered. Starting from the dynamic equilibrium relations and stress-strain-displacement relations, a dispersion system is given in a wave approach context. Next, expressions for the matrix systems governing the structural impedance, critical frequencies and ring frequency are given. The developed equations are applied to the calculation of the diffuse field transmission of an infinite cylinder. Predictions with the presented models are compared to results presented in the literature for both laminate composite and sandwich composite configurations. They confirm the accuracy of both models and the general nature of the presented discrete thick laminate composite model. © 2005 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Ghinet2006745, author = {Ghinet, S. and Atalla, N. and Osman, H.}, title = {Diffuse field transmission into infinite sandwich composite and laminate composite cylinders}, journal = {Journal of Sound and Vibration}, year = {2006}, volume = {289}, number = {4-5}, pages = {745-778}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33644542715&doi=10.1016%2fj.jsv.2005.02.028&partnerID=40&md5=ea4d9200694429c1ecfa6c513eedd81e}, doi = {https://doi.org/10.1016/j.jsv.2005.02.028} } |
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Horoshenkov, K., Khan, A., Sgard, F., Bécot, F.-X., Jaouen, L., Renaud, A., Amirouche, N., Hübelt, J., Pompoli, F., Prodi, N., Bonfiglio, P., Lauriks, W., Boeckx, L., Pispola, G., Asdrubali, F. and Atalla, N. | Reproducibility experiments on measuring acoustical and related non-Acoustical parameters of porous media (round-robin tests) | 2006 | 13th International Congress on Sound and Vibration 2006, ICSV 2006 Vol. 1, pp. 300-307 |
conference | URL |
Abstract: A series of reproducibility experiments on the characterisation of acoustical parameters of selected samples of porous media is carried out on a range of porous samples in several independent laboratories in Europe and North America. The studied acoustical characteristics are the characteristic acoustic impedance and complex propagation constant. The data on the normal incidence, plane wave sound absorption coefficient is presented in this paper. The assessment of the related geometrical parameters required for model, namely the steady-state flow resistivity, porosity, tortuosity, viscous and thermal characteristic lengths and thermal permeability, will be discussed in the oral presentation. Detailed procedures related to sample preparation, installation are discussed together with data on the material property variation observed between individual material samples and laboratories.© (2006) by the International Institute of Acoustics & Vibration. | |||||
BibTeX:
@conference{Horoshenkov2006300, author = {Horoshenkov, K.V. and Khan, A. and Sgard, F. and Bécot, F.-X. and Jaouen, L. and Renaud, A. and Amirouche, N. and Hübelt, J. and Pompoli, F. and Prodi, N. and Bonfiglio, P. and Lauriks, W. and Boeckx, L. and Pispola, G. and Asdrubali, F. and Atalla, N.}, title = {Reproducibility experiments on measuring acoustical and related non-Acoustical parameters of porous media (round-robin tests)}, journal = {13th International Congress on Sound and Vibration 2006, ICSV 2006}, year = {2006}, volume = {1}, pages = {300-307}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883335435&partnerID=40&md5=ad7a41ac7588c45258753fb4508350dc} } |
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Mencik, J.-M. and Berry, A. | A diffusion model for a one-dimensional structure, coupled with an auxiliary system | 2006 | Journal of Sound and Vibration Vol. 294(4), pp. 894-915 |
article | DOI URL |
Abstract: This paper extends the concept of a local energy approach to homogeneous structures which are coupled with an auxiliary resonant system. The case of a one-dimensional homogeneous master structure (bar, beam) coupled over its length with a homogeneous auxiliary system composed of resonant arbitrary subsystems is analyzed. It is shown that under specific assumptions, the vibrational energy density of the coupled master structure can be predicted by solving a simple energetic boundary value problem that accounts for the mechanical coupling with the auxiliary subsystem. In the context of vibrational energy propagation, an important question is whether heterogeneity introduced by the auxiliary system enhances the diffusive behavior of the master structure. Numerical results for various types of auxiliary systems show that the effective diffusion coefficient of the coupled system is generally increased compared to the uncoupled master structure. © 2006 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Mencik2006894, author = {Mencik, J.-M. and Berry, A.}, title = {A diffusion model for a one-dimensional structure, coupled with an auxiliary system}, journal = {Journal of Sound and Vibration}, year = {2006}, volume = {294}, number = {4}, pages = {894-915}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646747880&doi=10.1016%2fj.jsv.2005.12.036&partnerID=40&md5=417ecc5d64d8290e6f3a424fbccb0027}, doi = {https://doi.org/10.1016/j.jsv.2005.12.036} } |
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Micheau, P., Chatellier, L., Laumonier, J. and Gervais, Y. | Stability analysis of active control of self-sustained pressure fluctuations due to flow over a cavity | 2006 | Journal of the Acoustical Society of America Vol. 119(3), pp. 1496-1503 |
article | DOI URL |
Abstract: The problem addressed in this paper is the stability analysis of self-sustained pressure fluctuations due to low Mach number turbulent flow over a large shallow cavity in a wing-shaped model. In the studied configuration, sound pressure was generated by the instability of the mixing layer. An original active device, a vibrating surface located at the trailing edge, and an adjustable narrow-band controller were used to control the self-oscillation: to amplify it in an open loop, and to attenuate it in a closed loop. A complete analysis of the system based on the describing function analysis is presented. Experimental data, obtained in an Eiffel-type wind-tunnel compare favorably with the prediction of the model. With the active control, the instability is controlled: the pressure fluctuations measured in the cavity are attenuated to the ground level. Moreover, with the proposed model and the original device, the equivalent volume velocity of the unstable mixing layer and the acoustic feedback gain can be experimentally estimated. © 2006 Acoustical Society of America. | |||||
BibTeX:
@article{Micheau20061496, author = {Micheau, P. and Chatellier, L. and Laumonier, J. and Gervais, Y.}, title = {Stability analysis of active control of self-sustained pressure fluctuations due to flow over a cavity}, journal = {Journal of the Acoustical Society of America}, year = {2006}, volume = {119}, number = {3}, pages = {1496-1503}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33644650447&doi=10.1121%2f1.2161635&partnerID=40&md5=7073ae531410de961094a0603c700f23}, doi = {https://doi.org/10.1121/1.2161635} } |
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Micheau, P. | Complex envelope controller for active flow control of self-oscillating pressures | 2006 | Proceedings of the Eight IASTED International Conference on Control and Applications Vol. 2006, pp. 303-307 |
conference | URL |
Abstract: This paper presents the use of a complex envelope approach to control a self-oscillating pressure oscillation due to a grazing flow. The main advantage of the complex envelope approach is to use the Landau equation to model the phenomena, and to control it in real-time. Experimentations were performed with grazing flows over a resonant tube. The experimental results shown the efficiency of the approach to control the self-oscillation and to identify the parameters of the reduced model. | |||||
BibTeX:
@conference{Micheau2006303, author = {Micheau, P.}, title = {Complex envelope controller for active flow control of self-oscillating pressures}, journal = {Proceedings of the Eight IASTED International Conference on Control and Applications}, year = {2006}, volume = {2006}, pages = {303-307}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34047099810&partnerID=40&md5=8fa3fd768227b457f80a21245c0d4fcb} } |
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Micheau, P., Oddo, R. and Lecours, G. | Engine speed limiter for watercrafts | 2006 | IEEE Transactions on Control Systems Technology Vol. 14(3), pp. 579-585 |
article | DOI URL |
Abstract: Engine speed limiters are safety devices designed to prevent an engine from exceeding a predetermined high speed. The speed limiter herewith presented is designed for large and sudden load variations which require accurate and fast air-fuel ratio control. It is based on feedback linearization and online estimation of the load torque. Experimental testing was conducted with a Sea-Doo personal watercraft. A system was used to bypass the engine's electronic control unit (ECU) injector commands in order to use those of the new controller. Experimental results indicate that it reaches higher performances than the usual ECU injection cutoff strategy. © 2006 IEEE. | |||||
BibTeX:
@article{Micheau2006579, author = {Micheau, P. and Oddo, R. and Lecours, G.}, title = {Engine speed limiter for watercrafts}, journal = {IEEE Transactions on Control Systems Technology}, year = {2006}, volume = {14}, number = {3}, pages = {579-585}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646087418&doi=10.1109%2fTCST.2006.872508&partnerID=40&md5=c5b7ea71e7e58b977cb0d683fe0ed77a}, doi = {https://doi.org/10.1109/TCST.2006.872508} } |
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Micheau, P. and Renault, S. | Active control of the complex envelope associated with a low damped mode | 2006 | Mechanical Systems and Signal Processing Vol. 20(3), pp. 646-661 |
article | DOI URL |
Abstract: The active control of vibration consists of generating an extra force in order to decrease the level of vibration. The problem with controlling complex structures is to shift from a higher order system to a reduced order decoupled system. This paper proposes the use a narrow-band approach to control one low damped mode among others. The originality of this paper is in the association of complex envelopes with both the narrow-band signals and the impulse response of the reduced order system. As a result, an explicit adaptive controller of complex envelopes is tuned according to a pole placement method. Experiments with a plate show the efficiency of the approach for different types of band-pass excitations: chirp, sinusoidal and band-pass noise. The main advantages of the complex envelope approach are an extremely reduced order system, consequently the numerical implementation is simplified. © 2005 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Micheau2006646, author = {Micheau, P. and Renault, S.}, title = {Active control of the complex envelope associated with a low damped mode}, journal = {Mechanical Systems and Signal Processing}, year = {2006}, volume = {20}, number = {3}, pages = {646-661}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-28844502295&doi=10.1016%2fj.ymssp.2005.05.004&partnerID=40&md5=3cc82c320c5cb797f1535bcd0328bf6f}, doi = {https://doi.org/10.1016/j.ymssp.2005.05.004} } |
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Panneton, R. and Olny, X. | Acoustical determination of the parameters governing viscous dissipation in porous media | 2006 | Journal of the Acoustical Society of America Vol. 119(4), pp. 2027-2040 |
article | DOI URL |
Abstract: Analytical solutions are derived to extract from dynamic density the macroscopic parameters governing viscous dissipation of sound waves in open-cell porous media. While dynamic density is obtained from acoustical techniques, the analytical solutions are derived from the model describing this dynamic density. Here, semiphenomenological models by Johnson et al. and by Wilson are investigated. Assuming dynamic density, open porosity, and static airflow resistivity known, analytical solutions derived from the Johnson et al. model yield geometrical tortuosity and viscous characteristic dimension. For the Wilson model, only dynamic density needs to be known. In this case, analytical solutions yield - for the first time - Wilson's density parameter and vorticity-mode relaxation time. To alleviate constraints on the Johnson et al. model, an extrapolation approach is proposed to avoid prior knowledge of static resistivity. This approach may also be used to determine this latter parameter. The characterization methods are tested on three materials covering a wide range of static airflow resistivities (2300-150 100 Ns/m4), frame rigidities (soft and rigid), and pore geometries (cells and fibers). It is shown that the analytical solutions can be used to assess the validity of the descriptive models for a given material. © 2006 Acoustical Society of America. | |||||
BibTeX:
@article{Panneton20062027, author = {Panneton, R. and Olny, X.}, title = {Acoustical determination of the parameters governing viscous dissipation in porous media}, journal = {Journal of the Acoustical Society of America}, year = {2006}, volume = {119}, number = {4}, pages = {2027-2040}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645329345&doi=10.1121%2f1.2169923&partnerID=40&md5=c576f8086d776d7f4524d0872443bc9e}, doi = {https://doi.org/10.1121/1.2169923} } |
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Pasco, Y., Pinsoniiault, J., Berry, A., Masson, P. and Micheau, P. | Time reversal method for damage detection of cracked plates in the medium frequency range: The case of wavelength-size cracks | 2006 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 6176 |
conference | DOI URL |
Abstract: The use of time reversal methods for localization and characterization of damages in plates is usually combined with high frequency guided waves in a local elastic wave propagation formulation. In such a situation, pulses and echos may be clearly separated in time. As a consequence, the diffracted field on a damage with large geometrical dimensions compared to the wavelength used for wave propagation allows to consider the structure itself as "near infinite" because the modal behavior is not apparent. However, those high frequencies may not be required and in the presented approach, medium frequencies are used and boundary conditions need to be considered. The interest of this frequency range is in using lightweight signal processing devices limited to low data transfer rates as expected for in flight fuselage skin inspections. It also allows to filter artifacts like very small damages in the structure. This study focuses on the case of wavelengths which are in the order of the largest geometrical dimension of the cracks. In the paper, a modelling tool is first extended to describe the vibration behavior of pristine and damaged finite thin plates in the low and medium frequency range below 50 kHz. The proposed analytical model employs a Hierarchical Trigonometric Functions Set (HTFS) to characterize homogeneous plates with through cracks. To approximate the effect of a small crack in a plate for all combinations of classical boundary conditions, high order approximation functions are required. The proposed approach takes the advantage of the stability of the HTFS for these high orders. A notable advantage of this model is that it does not require a dense uniform meshing of the plate, with a minimum of 10 nodes per wavelength, as most finite element models require. The time reversal concept introduced before is thus validated with this model for a finite plate with known boundary conditions. Experimental validation of the model is conducted in the time domain for pristine and cracked plate structures and shows great potential for crack detection. | |||||
BibTeX:
@conference{Pasco2006, author = {Pasco, Y. and Pinsoniiault, J. and Berry, A. and Masson, P. and Micheau, P.}, title = {Time reversal method for damage detection of cracked plates in the medium frequency range: The case of wavelength-size cracks}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2006}, volume = {6176}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749574986&doi=10.1117%2f12.658612&partnerID=40&md5=c1c13f11f39a47c5a39bf52655f44bd0}, doi = {https://doi.org/10.1117/12.658612} } |
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Pasco, Y. and Berry, A. | Consideration of piezoceramic actuator nonlinearity in the active isolation of deterministic vibration | 2006 | Journal of Sound and Vibration Vol. 289(3), pp. 481-508 |
article | DOI URL |
Abstract: There is an increasing need to effectively control micro-vibration in such fields as metrology, optics and micro-electronics. This paper describes the design of an adaptive feedforward strategy for vibration isolation of harmonic disturbance using a piezoelectric actuator with hysteretic behavior. A nonlinear analytical model of the piezoelectric actuator including a ferroelectric-like behavior is built using a Preisach model of hysteresis. Pre-multiplication of a single-frequency reference signal by the nonlinear model of the stack is investigated in order to effectively compensate the actuator nonlinearity. It is observed that a simple linear model of the stack is sufficient in the adaptation of a filtered-X LMS feedforward controller to effectively compensate the actuator nonlinearity, provided the reference signal has frequency components at the disturbance frequency and its higher harmonics. © 2005 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Pasco2006481, author = {Pasco, Y. and Berry, A.}, title = {Consideration of piezoceramic actuator nonlinearity in the active isolation of deterministic vibration}, journal = {Journal of Sound and Vibration}, year = {2006}, volume = {289}, number = {3}, pages = {481-508}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-27744481940&doi=10.1016%2fj.jsv.2005.02.036&partnerID=40&md5=135d31f76f90c10233fc90522ba800b5}, doi = {https://doi.org/10.1016/j.jsv.2005.02.036} } |
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Quaegebeur, N. and Chaigne, A. | On the infuence of the geometry on radiation for electrodynamic loudspeakers | 2006 | Audio Engineering Society - 120th Convention Spring Preprints 2006 Vol. 2, pp. 770-775 |
conference | URL |
Abstract: The basic conception of loudspeakers remains unchanged for decades. In particular, the shape of the diaphragm is nowadays designed as the association of a spherical cap and a truncated cone. The present work focuses on the infuence of the shape of the diaphragm on the sound radiation. A temporal model based on spatial impulse response has been developed to predict the sound radiation of an axisymetrical source subjected to an impulse. It is shown that non-planar sources are less subject to o®-axis amplitude and phase variations than planar sources. the comparison between convex and concave geometries is also studied. It is shown that transients are more accurately reproduced by convex structures. | |||||
BibTeX:
@conference{Quaegebeur2006770, author = {Quaegebeur, N. and Chaigne, A.}, title = {On the infuence of the geometry on radiation for electrodynamic loudspeakers}, journal = {Audio Engineering Society - 120th Convention Spring Preprints 2006}, year = {2006}, volume = {2}, pages = {770-775}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866512892&partnerID=40&md5=ccedd4501ec8bc93c7c7a71351b0107a} } |
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Richard, S. and Champoux, Y. | Development of a metric related to the dynamic comfort of a road bike | 2006 | Conference Proceedings of the Society for Experimental Mechanics Series | conference | URL |
Abstract: Hand-transmitted vibration is one on the major concern about dynamic comfort on road bike. Indeed, after several hours on a rough or damaged road, the biker may experience hand tickling and soreness in the forearm. This paper presents the development of a metric that quantify the force transmitted to the cyclist by the handlebar. Also, the cyclist's sensitivity to this metric is evaluated before proceeding to comparison tests. The levels of energy transmitted to the cyclist are compared for different forks and different bikes. The new metric allows the determination of the degree of comfort of a road bike. | |||||
BibTeX:
@conference{Richard2006, author = {Richard, S. and Champoux, Y.}, title = {Development of a metric related to the dynamic comfort of a road bike}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2006}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861537896&partnerID=40&md5=a934ed5a47595d8e746c0585fd6583d0} } |
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Robert, R., Micheau, P. and Walti, H. | A supervisor for volume-controlled tidal liquid ventilator using independent piston pumps | 2006 | IFAC Proceedings Volumes (IFAC-PapersOnline) Vol. 6(PART 1), pp. 381-386 |
conference | URL |
Abstract: Liquid ventilation using perfluorochemicals (PFC) offers clear theoretical advantages over gas ventilation, such as decreased lung damage, recruitment of collapsed lung regions and lavage of inflammatory debris. This paper presents the control of a total liquid ventilator (TLV) dedicated to ventilate patients with completely filled lungs with a tidal volume of perfluorochemical liquid. The two independent piston pumps are volume controlled and pressure limited. Measurable pumping errors are corrected by a programmed supervisor module, which modifies the inserted or withdrawn volume. Pump independence also allows easy FRC modifications during ventilation. The prototype was tested on 5 healthy term newborn lambs (<5 days old). Copyright © 2006 IFAC. | |||||
BibTeX:
@conference{Robert2006381, author = {Robert, R. and Micheau, P. and Walti, H.}, title = {A supervisor for volume-controlled tidal liquid ventilator using independent piston pumps}, journal = {IFAC Proceedings Volumes (IFAC-PapersOnline)}, year = {2006}, volume = {6}, number = {PART 1}, pages = {381-386}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79961154836&partnerID=40&md5=e847dfe124b438dab888e6dda160cf70} } |
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Robert, R., Micheau, P., Cyr, S., Lesur, O., Praud, J.-P. and Walti, H. | A prototype of volume-controlled tidal liquid ventilator using independent piston pumps | 2006 | ASAIO Journal Vol. 52(6), pp. 638-645 |
article | DOI URL |
Abstract: Liquid ventilation using perfluorochemicals (PFC) offers clear theoretical advantages over gas ventilation, such as decreased lung damage, recruitment of collapsed lung regions, and lavage of inflammatory debris. We present a total liquid ventilator designed to ventilate patients with completely filled lungs with a tidal volume of PFC liquid. The two independent piston pumps are volume controlled and pressure limited. Measurable pumping errors are corrected by a programmed supervisor module, which modifies the inserted or withdrawn volume. Pump independence also allows easy functional residual capacity modifications during ventilation. The bubble gas exchanger is divided into two sections such that the PFC exiting the lungs is not in contact with the PFC entering the lungs. The heating system is incorporated into the metallic base of the gas exchanger, and a heat-sink-type condenser is placed on top of the exchanger to retrieve PFC vapors. The prototype was tested on 5 healthy term newborn lambs (<5 days old). The results demonstrate the efficiency and safety of the prototype in maintaining adequate gas exchange, normal acido-basis equilibrium, and cardiovascular stability during a short, 2-hour total liquid ventilator. Airway pressure, lung volume, and ventilation scheme were maintained in the targeted range. ©2006Amercian Society of Artificial Internal Organs. | |||||
BibTeX:
@article{Robert2006638, author = {Robert, R. and Micheau, P. and Cyr, S. and Lesur, O. and Praud, J.-P. and Walti, H.}, title = {A prototype of volume-controlled tidal liquid ventilator using independent piston pumps}, journal = {ASAIO Journal}, year = {2006}, volume = {52}, number = {6}, pages = {638-645}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33751202413&doi=10.1097%2f01.mat.0000249016.31910.11&partnerID=40&md5=ce0dfc6436a4ea26417c3d6451c111cf}, doi = {https://doi.org/10.1097/01.mat.0000249016.31910.11} } |
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Salissou, Y. and Panneton, R. | Comparison of methods for characterizing sound absorbing materials | 2006 | Canadian Acoustics - Acoustique Canadienne Vol. 34(3), pp. 32-33 |
article | URL |
Abstract: A study was conducted to characterize three samples of metal foam, using direct, indirect, and inverse methods to highlight that the methods may yield large variability in the found parameters. Direct measurement of the open porosity was performed, using the Archimedes principle. It provided a direct measured value of open porosity through measurement of sample weight in vacuum, in air, and predicted the measurement error. Analytical solutions were used to determine the static airflow resistivity, tortuosity, viscous characteristic dimension (VCD), and thermal characteristic dimension (TCD) of the material, assuming that dynamic density, dynamic bulk modulus, and open porosity were known. The inverse method was applied the tortuosity and the two characteristic lengths, assuming porosity and static resistivity to be known from direct measurements. The results show that the parameter values are in better agreement from one sample to another and the deviation from mean values are acceptable. | |||||
BibTeX:
@article{Salissou200632, author = {Salissou, Y. and Panneton, R.}, title = {Comparison of methods for characterizing sound absorbing materials}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2006}, volume = {34}, number = {3}, pages = {32-33}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750186541&partnerID=40&md5=e4b8df609ce44991993755a2d88328cd} } |
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Yettou, E.-M., Desrochers, A. and Champoux, Y. | Experimental study on the water impact of a symmetrical wedge | 2006 | Fluid Dynamics Research Vol. 38(1), pp. 47-66 |
article | DOI URL |
Abstract: In this paper, we report the results of our experimental investigation of the pressure distribution on a free-falling wedge upon entering water. Parameters such as the drop height, the deadrise angle and the mass of the wedge are related to the water pressure on the wedge and its dynamic behavior. Existing models that assumed a constant water-entry velocity of the wedge are compared with experimental data. In order to take into account the inherent variation in the velocity of a free-falling wedge, a combination of two models are proposed. This method gives an adequate approximation of the maximum pressures measured. © 2005 Published by The Japan Society of Fluid Mechanics and Elsevier B.V. All rights reserved. | |||||
BibTeX:
@article{Yettou200647, author = {Yettou, E.-M. and Desrochers, A. and Champoux, Y.}, title = {Experimental study on the water impact of a symmetrical wedge}, journal = {Fluid Dynamics Research}, year = {2006}, volume = {38}, number = {1}, pages = {47-66}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-29644439031&doi=10.1016%2fj.fluiddyn.2005.09.003&partnerID=40&md5=274cd4dfbeb5f4aa27705e42833a21fe}, doi = {https://doi.org/10.1016/j.fluiddyn.2005.09.003} } |
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Atalla, Y. and Panneton, R. | Inverse acoustical characterization of open cell porous media using impedance tube measurements | 2005 | Canadian Acoustics - Acoustique Canadienne Vol. 33(1), pp. 11-24 |
article | URL |
Abstract: Unlike porous models developed for particular absorbing materials and frequency ranges, the Johnson-Champoux-Allard model is a generalized model for sound propagation in porous materials over a wide range of frequencies. This model is nowadays used widely across the acoustic research community and by industrial sector. However to use this model, the knowledge, particularly, of the intrinsic material properties defining the model is necessary. Using the proposed porous model and with the knowledge of the intrinsic properties, the calculation of the desired acoustical indicators as well as the design and optimization of several acoustic treatments for noise reduction can be done efficiently and rapidly. The model of Johnson-Champoux-Allard is based on five intrinsic properties of the porous medium: the flow resistivity, the porosity, the tortuosity, the viscous characteristic length, and the thermal characteristic length. While the open porosity and airflow resistivity can be directly measured without great difficulties, the direct measurements of the three remaining properties are usually complex, less robust, or destructive. To circumvent the problem, an inverse characterization method based on impedance tube measurements is proposed. It is shown that this inverse acoustical characterization can yield reliable evaluations of the tortuosity, and the viscous and thermal characteristic lengths. The inversion algorithm contains an optimization process and hence it is verified that the identified optimal three parameter, even though derived from a mathematical optimum for a given experimental configuration (sample's thickness, measured frequency range), are the intrinsic properties of the characterized porous material. | |||||
BibTeX:
@article{Atalla200511, author = {Atalla, Y. and Panneton, R.}, title = {Inverse acoustical characterization of open cell porous media using impedance tube measurements}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2005}, volume = {33}, number = {1}, pages = {11-24}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-17444424898&partnerID=40&md5=eee10decf8ac5be607e2c75fffd6ad74} } |
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Atalla, N., Sgard, F. and Atalla, Y. | On the modeling of perforated plates and screens | 2005 | 12th International Congress on Sound and Vibration 2005, ICSV 2005 Vol. 1, pp. 315-322 |
conference | URL |
Abstract: There are several models and approaches for predicting the acoustic response of perforated plates and screens. Classical models are devoted to specific configurations: particular geometrical parameters including the size and shape of the perforations, excitations type, mounting of the screen (bonded vs. free), and interfacing media involved in multi-layers sound packages. This paper reviews these models and presents a simple and general model that can handle easily and automatically the miscellaneous configurations in the context of the transfer matrix method. In particular, it is shown that a perforated plate or screen can be modeled as an equivalent fluid following the Johnson-Allard approach with an equivalent tortuosity. This equivalent tortuosity is shown to depend on the media interfacing with the perforated system. Experimental results depicting various practical configurations are shown to corroborate the validity of the proposed model and to evaluate its performance compared to classical ones. | |||||
BibTeX:
@conference{Atalla2005315, author = {Atalla, N. and Sgard, F. and Atalla, Y.}, title = {On the modeling of perforated plates and screens}, journal = {12th International Congress on Sound and Vibration 2005, ICSV 2005}, year = {2005}, volume = {1}, pages = {315-322}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881597080&partnerID=40&md5=13894b659d1461e1e4257a92f7095f01} } |
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Bolduc, M., Atalla, N. and Wareing, A. | Measurement of SEA damping loss factor for complex structures | 2005 | SAE Technical Papers | article | DOI URL |
Abstract: Statistical Energy Analysis has become extremely popular over the last decade in the transportation industry. As a prediction tool, it offers appealing advantages such as, its wide frequency range and short computational time, which conventional methods do not offer. Prediction of the vibrational response of dynamical systems, whether it is by means of analytical methods, numerical methods or, as in our case, by statistical methods, requires in particular the damping characteristics of the structure's components. This work proposes a comparison study of the three techniques widely used to determine the loss factors of different complex structures ranging form simple flat plates to ribbed panels and sandwich composite panels in different mounting configurations. The studied structures are classically met in cars, aircraft and trains. They span both low and high damping configurations. The paper discusses the advantages and drawbacks of each method in the context of SEA modeling of complex structures. Copyright © 2005 SAE International. | |||||
BibTeX:
@article{Bolduc2005, author = {Bolduc, M. and Atalla, N. and Wareing, A.}, title = {Measurement of SEA damping loss factor for complex structures}, journal = {SAE Technical Papers}, year = {2005}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877393100&doi=10.4271%2f2005-01-2327&partnerID=40&md5=890f4f40f21e273946f42cccbaabe2c8}, doi = {https://doi.org/10.4271/2005-01-2327} } |
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Chaigne, A. and Quaegebeur, N. | Radiation of electrodynamical loudspeakers subjected to large amplitude motion | 2005 | Forum Acusticum Budapest 2005: 4th European Congress on Acustics, pp. 181-186 | conference | URL |
Abstract: Nonlinearities affect the behavior of electrodynamical loudspeakers subjected to large amplitude motion. As a consequence, the quality of sound reproduction might be degraded for high sound pressure level. In the low-frequency range, i.e. when the motion of the membrane can be reasonably described by a translating rigid body, the main mechanical source of linearity is due to the suspension. Measurements of the membrane velocity show that the amplitude of the motion is also significant at frequencies corresponding to eigenfrequencies of the system. Therefore, nonlinearity can also affect the behavior of the loudspeaker in the medium frequency range. In the high frequency range, resonances are less pronounced due to internal damping. In order to investigate this problem, a nonlinear model of the suspension was first developed. Comparison of this model with measurements of the second and third harmonics due to nonlinear distorsion of the velocity as a function of driving amplitude and frequency shows a good agreement. In a second step, the radiation of the membrane was calculated using a modal approach and compared to measurements. It has been observed that the directivity pattern of the loudspeaker is significantly affected by the driving amplitude, especially in the frequency domain corresponding to the eigenmodes of the coupled membrane-suspension system. | |||||
BibTeX:
@conference{Chaigne2005181, author = {Chaigne, A. and Quaegebeur, N.}, title = {Radiation of electrodynamical loudspeakers subjected to large amplitude motion}, journal = {Forum Acusticum Budapest 2005: 4th European Congress on Acustics}, year = {2005}, pages = {181-186}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864620951&partnerID=40&md5=bb9e36a88cf3a7f82d6e162c369f1033} } |
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Gauthier, P.-A., Berry, A. and Woszczyk, W. | Sound-field reproduction in-room using optimal control techniques: Simulations in the frequency domain | 2005 | Journal of the Acoustical Society of America Vol. 117(2), pp. 662-678 |
article | DOI URL |
Abstract: This paper describes the simulations and results obtained when applying optimal control to progressive sound-field reproduction (mainly for audio applications) over an area using multiple monopole loudspeakers. The model simulates a reproduction system that operates either in free field or in a closed space approaching a typical listening room, and is based on optimal control in the frequency domain. This rather simple approach is chosen for the purpose of physical investigation, especially in terms of sensing microphones and reproduction loudspeakers configurations. Other issues of interest concern the comparison with wave-field synthesis and the control mechanisms. The results suggest that in-room reproduction of sound field using active control can be achieved with a residual normalized squared error significantly lower than open-loop wave-field synthesis in the same situation. Active reproduction techniques have the advantage of automatically compensating for the room's natural dynamics. For the considered cases, the simulations show that optimal control results are not sensitive (in terms of reproduction error) to wall absorption in the reproduction room. A special surrounding configuration of sensors is introduced for a sensor-free listening area in free field. © 2005 Acoustical Society of America. | |||||
BibTeX:
@article{Gauthier2005662, author = {Gauthier, P.-A. and Berry, A. and Woszczyk, W.}, title = {Sound-field reproduction in-room using optimal control techniques: Simulations in the frequency domain}, journal = {Journal of the Acoustical Society of America}, year = {2005}, volume = {117}, number = {2}, pages = {662-678}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-13544265400&doi=10.1121%2f1.1850032&partnerID=40&md5=52b58cee9def482bc446a5b7619a0b31}, doi = {https://doi.org/10.1121/1.1850032} } |
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Gérard, A., Berry, A. and Masson, P. | Control of tonal noise from subsonic axial fan. Part 1: Reconstruction of aeroacoustic sources from far-field sound pressure | 2005 | Journal of Sound and Vibration Vol. 288(4-5), pp. 1049-1075 |
article | DOI URL |
Abstract: An inverse method is investigated to evaluate the unsteady rotating forces (dipole strength distribution) acting by the fan on the fluid from far-field acoustic pressure measurements. A development based on the tonal noise generated by a propeller is used to derive a discretized form of the direct problem. The inversion of this direct problem is ill-posed and requires optimization technique to stabilize the solution for small perturbations in the measured acoustic input data. The reconstruction reveals that the conditioning of the inverse model depends on the aeroacoustic source and far-field sensor locations as well as on the frequency under investigation. Simulations show that an adequate choice of a regularization parameter leads to a satisfactory reconstruction of imposed unsteady rotating forces in the presence of measurement noise, and a correct localization of acoustic "hot spots" on the radiation surface. Preliminary experimental results also show the ability to extrapolate the radiated sound field at blade passage frequency (BPF), and harmonics, from the reconstructed forces. These data are exploited in the second part of this paper to evaluate various active control strategies for tonal fan noise. © 2005 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Gérard20051049, author = {Gérard, A. and Berry, A. and Masson, P.}, title = {Control of tonal noise from subsonic axial fan. Part 1: Reconstruction of aeroacoustic sources from far-field sound pressure}, journal = {Journal of Sound and Vibration}, year = {2005}, volume = {288}, number = {4-5}, pages = {1049-1075}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-26444532831&doi=10.1016%2fj.jsv.2005.01.023&partnerID=40&md5=45c0c483b991fe3ad6dd6e09361dd277}, doi = {https://doi.org/10.1016/j.jsv.2005.01.023} } |
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Gérard, A., Berry, A. and Masson, P. | Control of tonal noise from subsonic axial fan. Part 2: Active control simulations and experiments in free field | 2005 | Journal of Sound and Vibration Vol. 288(4-5), pp. 1077-1104 |
article | DOI URL |
Abstract: This paper deals with the global control of engine cooling fan noise in free field at the Blade Passing Frequency (BPF) and its first harmonic. The aim of this paper is to investigate the feasibility of using a single loudspeaker in front of the fan to cancel the tonal noise. A simplified model of fan noise, which only takes into account the most radiating circumferential mode of the forces acting by the fan on the fluid, is first combined with an unbaffled loudspeaker model to predict the residual sound field for various sensor configurations. Metrics for global control such as sound directivity or sound power attenuation reveal that the control is effective with this simplified model in the whole space at low frequency, depending on the number and location of the error sensors. However, for non-homogeneous flow, other circumferential modes may contribute to the sound radiation and then, the inverse model described in the companion paper is used to provide a more accurate extrapolated sound field from the reconstructed unsteady aerodynamic forces acting by the fan on the fluid. Simulation results demonstrate the global control in the downstream half space of the blade passing frequency and its first harmonic using a single error microphone and a single control source. A single-input-single-output (SISO) adaptive feedforward controller is implemented experimentally to drive the control loudspeaker. The tones at the BPF and at its first harmonic are attenuated by up to 28 and 18 dB, respectively at the far field error microphone. © 2005 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Gérard20051077, author = {Gérard, A. and Berry, A. and Masson, P.}, title = {Control of tonal noise from subsonic axial fan. Part 2: Active control simulations and experiments in free field}, journal = {Journal of Sound and Vibration}, year = {2005}, volume = {288}, number = {4-5}, pages = {1077-1104}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-26444500988&doi=10.1016%2fj.jsv.2005.01.022&partnerID=40&md5=6b1b1201d277d6ef1349d921d9e463f2}, doi = {https://doi.org/10.1016/j.jsv.2005.01.022} } |
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Gérard, A., Berry, A., Masson, P., Tartarin, J. and Gervais, Y. | Unsteady lift and flow velocity evaluation for subsonic fans using inverse aeroacoustic models | 2005 | Collection of Technical Papers - 11th AIAA/CEAS Aeroacoustics Conference Vol. 4, pp. 2541-2554 |
conference | URL |
Abstract: This paper deals with the inversion of the Blake model for tonal noise from subsonic fans. The unsteady lift formulation is first used to reconstruct the circumferential blade loading variations from the tonal noise radiation in free field. Then the unsteady lift is related to the inflow velocity distortions by a compressible Sears-like functions. Discretizing the lift and velocity direct models leads to ill-conditionned aeroacoustic transfer matrices. The Tikhonov regularization technique is used to stabilize the inversion. The L-curve and its curvature are plotted to choose the regularization parameter such that the source strength vectors are optimally reconstructed. One experimental case is considered to demonstrate the capability of the inverse model to reconstruct the variation of loading and inflow velocity during the rotation of an an automotive engine cooling fan. Copyright © 2005 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. | |||||
BibTeX:
@conference{Gérard20052541, author = {Gérard, A. and Berry, A. and Masson, P. and Tartarin, J. and Gervais, Y.}, title = {Unsteady lift and flow velocity evaluation for subsonic fans using inverse aeroacoustic models}, journal = {Collection of Technical Papers - 11th AIAA/CEAS Aeroacoustics Conference}, year = {2005}, volume = {4}, pages = {2541-2554}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-29244477559&partnerID=40&md5=4226a768eb719039e915a3ca8397dfb7} } |
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Ghinet, S., Atalla, N. and Osman, H. | The transmission loss of curved laminates and sandwich composite panels | 2005 | Journal of the Acoustical Society of America Vol. 118(2), pp. 774-790 |
article | DOI URL |
Abstract: The paper describes a model to calculate the transmission loss of both curved laminate and sandwich composite panels within statistical energy analysis (SEA) context. The vibro-acoustic problem is developed following a wave approach based on a discrete lamina description. Each lamina is considered to consist of membrane, bending, transverse shearing and rotational inertia behaviors. Moreover, the orthotropic ply angle of each lamina is considered. Using such a discrete lamina description, the dispersion behaviors of the panel are correctly represented. Using the dispersion curves, the radiation efficiency, the modal density, as well as, the nonresonant and the resonant transmission are computed. Moreover, expression for the evaluation of the ring frequency and the critical frequencies of such panels is given. The described model is shown to handle accurately, both laminate and sandwich composite shells. Additionally, a transmission loss test is presented to confirm the validity of the presented model. © 2005 Acoustical Society of America. | |||||
BibTeX:
@article{Ghinet2005774, author = {Ghinet, S. and Atalla, N. and Osman, H.}, title = {The transmission loss of curved laminates and sandwich composite panels}, journal = {Journal of the Acoustical Society of America}, year = {2005}, volume = {118}, number = {2}, pages = {774-790}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-23744470317&doi=10.1121%2f1.1932212&partnerID=40&md5=4ad692ef781f3e8b8960935a50882821}, doi = {https://doi.org/10.1121/1.1932212} } |
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Jaouen, L., Brouard, B., Atalla, N. and Langlois, C. | A simplified numerical model for a plate backed by a thin foam layer in the low frequency range | 2005 | Journal of Sound and Vibration Vol. 280(3-5), pp. 681-698 |
article | DOI URL |
Abstract: This paper presents a simplified numerical model based on a hierarchical trigonometric functions set to predict the low frequency vibration behaviour of a plate backed by a thin foam layer. The base metal plate is excited in bending vibrations with a point load and can have various boundary conditions. The poro-elastic layer is modelled using the mixed displacement-pressure formulation of the Biot-Allard's theory. The base plate and the solid phase of the porous medium are described as an equivalent visco-elastic plate. The poro-elastic's fluid phase is coupled with the equivalent plate displacements. Comparisons with complete three-dimensional poro-elastic finite element solutions and experimental data are presented to define a domain of validation for the proposed simplified model. © 2003 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Jaouen2005681, author = {Jaouen, L. and Brouard, B. and Atalla, N. and Langlois, C.}, title = {A simplified numerical model for a plate backed by a thin foam layer in the low frequency range}, journal = {Journal of Sound and Vibration}, year = {2005}, volume = {280}, number = {3-5}, pages = {681-698}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-10444241944&doi=10.1016%2fj.jsv.2003.12.038&partnerID=40&md5=7928bb26f8f670326cb68617249b5f09}, doi = {https://doi.org/10.1016/j.jsv.2003.12.038} } |
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Mencik, J.-M. and Berry, A. | A theoretical formulation of the dynamical response of a master structure coupled with elastic continuous fuzzy subsystems with discrete attachments | 2005 | Journal of Sound and Vibration Vol. 280(3-5), pp. 1031-1050 |
article | DOI URL |
Abstract: We present the formulation of the dynamic response of a master structure coupled with a locally homogeneous and orthotropic structural fuzzy, with discrete attachment, composed of elastic continuous fuzzy subsystems. As introduced by Soize, the master structure is the part of the coupled system which is accessible by classical modeling, whereas the structural fuzzy represents systems connected to the master structure, whose characteristics are imprecisely known. A deterministic formulation of the boundary impedance of a general continuous structural fuzzy, which models its action on the master structure, is derived: it is shown that the formulation is different from the solution proposed by Soize in the context of the type I fuzzy law, established from the deterministic model of a linear oscillator excited by its support. Finally, the general boundary impedance is applied to the special situation of a structural fuzzy composed of elastic bars whose geometrical parameters are randomly defined, and numerical results are presented. © 2004 Published by Elsevier Ltd. | |||||
BibTeX:
@article{Mencik20051031, author = {Mencik, J.-M. and Berry, A.}, title = {A theoretical formulation of the dynamical response of a master structure coupled with elastic continuous fuzzy subsystems with discrete attachments}, journal = {Journal of Sound and Vibration}, year = {2005}, volume = {280}, number = {3-5}, pages = {1031-1050}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-10444235115&doi=10.1016%2fj.jsv.2004.01.053&partnerID=40&md5=bca4496b1ca1a49e94842c5ad3f5579a}, doi = {https://doi.org/10.1016/j.jsv.2004.01.053} } |
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Michaud, F., Létourneau, D., Lepage, P., Morin, Y., Gagnon, F., Giguère, P., Beaudry, É., Brosseau, Y., Côté, C., Duquette, A., Laplante, J.-F., Legault, M.-A., Moisan, P., Ponchon, A., Raïevsky, C., Roux, M.-A., Salter, T., Valin, J.-M., Caron, S., Masson, P., Kabanza, F. and Lauria, M. | A brochette of socially interactive robots | 2005 | Proceedings of the National Conference on Artificial Intelligence Vol. 4, pp. 1733-1734 |
conference | URL |
Abstract: The design of interactive mobile robots is a multidisciplinary endeavor that profits from putting robots with people and studying their effects and impacts. To do so, two main issues must be addressed: giving robots capabilities in order to interact in meaningful and efficient ways with people, and the ability to move in human settings. This paper briefly describes four robotic platforms that are going to be demonstrated at the AAAI 2005 Robot Competition. Copyright © 2005, American Association for Artificial Intelligence (www.aaai.org). All rights reserved. | |||||
BibTeX:
@conference{Michaud20051733, author = {Michaud, F. and Létourneau, D. and Lepage, P. and Morin, Y. and Gagnon, F. and Giguère, P. and Beaudry, É. and Brosseau, Y. and Côté, C. and Duquette, A. and Laplante, J.-F. and Legault, M.-A. and Moisan, P. and Ponchon, A. and Raïevsky, C. and Roux, M.-A. and Salter, T. and Valin, J.-M. and Caron, S. and Masson, P. and Kabanza, F. and Lauria, M.}, title = {A brochette of socially interactive robots}, journal = {Proceedings of the National Conference on Artificial Intelligence}, year = {2005}, volume = {4}, pages = {1733-1734}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-29344473136&partnerID=40&md5=75c975f187c026455b81a5f36fb13c88} } |
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Michaud, F., Côté, C., Létourneau, D., Brosseau, Y., Valin, J.-M., Beaudry, É., Raïevsky, C., Ponchon, A., Moisan, P., Lepage, P., Morin, Y., Gagnon, F., Giguère, P., Duquette, A., Laplante, J.-F., Roux, M.-A., Legault, M.-A., Salter, T., Caron, S., Frenette, P., Lauria, M., Kabanza, F. and Masson, P. | Socially interactive robots for real life use | 2005 | AAAI Workshop - Technical Report Vol. WS05-11, pp. 45-52 |
conference | URL |
Abstract: Designing interactive mobile robots is a multidisciplinary endeavor that profits from having people interact with robots in different contexts, observing the effects and impacts. To do so, two main issues must be addressed: integrating perceptual and decision-making capabilities in order to interact in meaningful and efficient ways with people, and the ability to move in human settings. This paper describes four robotic platforms demonstrated at the AAAI 2005 Robot Competition, each addressing these issues in their own ways. Copyright © 2002, American Association for Artificial Intelligence. All rights reserved. | |||||
BibTeX:
@conference{Michaud200545, author = {Michaud, F. and Côté, C. and Létourneau, D. and Brosseau, Y. and Valin, J.-M. and Beaudry, É. and Raïevsky, C. and Ponchon, A. and Moisan, P. and Lepage, P. and Morin, Y. and Gagnon, F. and Giguère, P. and Duquette, A. and Laplante, J.-F. and Roux, M.-A. and Legault, M.-A. and Salter, T. and Caron, S. and Frenette, P. and Lauria, M. and Kabanza, F. and Masson, P.}, title = {Socially interactive robots for real life use}, journal = {AAAI Workshop - Technical Report}, year = {2005}, volume = {WS05-11}, pages = {45-52}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892899851&partnerID=40&md5=ff9aa478db43723f5b57ae4676669b3d} } |
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Michaud, F., Laplante, J.-F., Larouche, H., Duquette, A., Caron, S., Létourneau, D. and Masson, P. | Autonomous spherical mobile robot for child-development studies | 2005 | IEEE Transactions on Systems, Man, and Cybernetics Part A:Systems and Humans. Vol. 35(4), pp. 471-480 |
article | DOI URL |
Abstract: This paper presents the design process of a spherical robot capable of autonomous motion, and demonstrates how it can become a tool in child-development studies. The robot, named Roball, is capable of intentional self-propelled movements and can generate various interplay situations using motion, messages, sounds, illuminated parts and other sensors. Such capabilities allow Roball to interact with young children in simple and interesting ways, and to provide the potential of contributing to the development of their language, affective, motor, intellectual and social skills. Trials done with 12-24-month-old children demonstrate how Roball can be used to study children's interest in a self-propelled and intentional device. An experimental methodology to conduct such studies is presented: it is based on quantitative and qualitative techniques to evaluate interactions, thus enabling the identification of challenges and opportunities in child-robot interaction studies. © 2005 IEEE. | |||||
BibTeX:
@article{Michaud2005471, author = {Michaud, F. and Laplante, J.-F. and Larouche, H. and Duquette, A. and Caron, S. and Létourneau, D. and Masson, P.}, title = {Autonomous spherical mobile robot for child-development studies}, journal = {IEEE Transactions on Systems, Man, and Cybernetics Part A:Systems and Humans.}, year = {2005}, volume = {35}, number = {4}, pages = {471-480}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-22244458916&doi=10.1109%2fTSMCA.2005.850596&partnerID=40&md5=ebd62f71d51e517bc258e904e2ff9a13}, doi = {https://doi.org/10.1109/TSMCA.2005.850596} } |
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Micheau, P. and Coirault, P. | A harmonic controller of engine speed oscillations for hybrid vehicles | 2005 | IFAC Proceedings Volumes (IFAC-PapersOnline) Vol. 16, pp. 19-24 |
conference | URL |
Abstract: in conventional internal combustion engines, the periodic fuel combustion in cylinders and oscillating masses result in pulsating engine torque. in hybrid powertrains, the electrical motor can be used to control such pulsations. The main originality of this paper is to present an efficient harmonic controller synchronized with the engine speed: the feedback law controls the Fourier parameters of the command. For time-variation of the engine speed, the adaptation of the harmonic controller ensures the convergence of the command. Conditions of stability are given, and the robustness of the approach is presented. Simulation shows that the undesirable harmonics of engine speed oscillations are perfectly rejected in spite of engine speed variation. Copyright © 2005 IFAC. | |||||
BibTeX:
@conference{Micheau200519, author = {Micheau, P. and Coirault, P.}, title = {A harmonic controller of engine speed oscillations for hybrid vehicles}, journal = {IFAC Proceedings Volumes (IFAC-PapersOnline)}, year = {2005}, volume = {16}, pages = {19-24}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960735506&partnerID=40&md5=ec1df2eb1e4236bee2fcb5faf9c12a62} } |
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Micheau, P. and Berry, A. | Stability conditions in decentralized active vibration control of a flexible plate | 2005 | 19th National Conference on Noise Control Engineering 2005, Noise-Con 05 Vol. 1, pp. 636-643 |
conference | URL |
Abstract: This paper presents the analysis of decentralized active control of periodic panel vibration using multiple pairs combining PZT actuators and PVDF sensors distributed (and not necessarily collocated) on the panel. Frequency domain gradient and Newton-Raphson adaptation of decentralized control were analyzed, both in terms of performance and stability conditions. The stabilization of the closed loop by adjusting the convergence coefficient was especially investigated through an adjustable control effort term in the quadratic cost function. Various necessary or sufficient stability conditions derived from the transfer matrix were obtained and ranked from the most restrictive to the less restrictive condition. One of them, the strictly positive real condition of the transfer matrix appears to be very useful. This stability condition is obtained when the open-loop system is dissipative. Simulation and experimental results are presented in the case of a simply-supported panel with 4 PZT-PVDF pairs distributed on the panel. The experimental results were obtained with a decentralized harmonic controller demonstrated equivalent to any narrow band disturbance control methods. Decentralized vibration control is shown to be highly dependent of the actuator and sensor configurations, but can be as effective as a fully centralized control even when the transfer matrix is not diagonaldominant. | |||||
BibTeX:
@conference{Micheau2005636, author = {Micheau, P. and Berry, A.}, title = {Stability conditions in decentralized active vibration control of a flexible plate}, journal = {19th National Conference on Noise Control Engineering 2005, Noise-Con 05}, year = {2005}, volume = {1}, pages = {636-643}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870189108&partnerID=40&md5=1ea1d4a93862264034249108a66acc10} } |
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Osman, H., Ghinet, S. and Atalla, N. | Parametric study of transmission loss of a cureved sandwich composite panel | 2005 | 12th International Congress on Sound and Vibration 2005, ICSV 2005 Vol. 6, pp. 5246-5253 |
conference | URL |
Abstract: This paper applies a newly developed wave approach for a parametric study of the transmission loss of a curved sandwich composite panel. This approach considers the effects of membrane, bending, transverse shearing as well as rotational inertia in all the layers composing the panel. Only the main features of the model are briefly presented here. This model is used to perform a parametric study of the effects of varying the material properties, ply thicknesses, and orientation on the TL. The wave approach model was applied for a test panel and a good comparison to the measured TL was obtained. The TL results together with comparisons of test and derived ring and critical frequencies are presented. The close agreement lends credence to the conclusions of the parametric study. | |||||
BibTeX:
@conference{Osman20055246, author = {Osman, H. and Ghinet, S. and Atalla, N.}, title = {Parametric study of transmission loss of a cureved sandwich composite panel}, journal = {12th International Congress on Sound and Vibration 2005, ICSV 2005}, year = {2005}, volume = {6}, pages = {5246-5253}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881560540&partnerID=40&md5=28f1df7f514c714ddd33d8b2048a4a86} } |
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Panneton, R. and Gros, E. | A missing mass method to measure the open porosity of porous solids | 2005 | Acta Acustica united with Acustica Vol. 91(2), pp. 342-348 |
article | URL |
Abstract: This paper presents a method for measuring the open porosity of porous solids when the mass density of the solid phase constituent is unknown. In this case, the determination of the open porosity requires the determination of the volume of the solid phase. The proposed method is based on the measurement of the apparent (in-air) and true (in-vacuum) masses of a porous solid, where an in-air "missing mass" is found and related to the volume of the solid phase through the Archimedes' principle. The precision of the method in relation with the used experimental set-up is studied. The error on the measured open porosity is estimated only in terms of the bulk volume of the test sample and the balance readability. Experimental tests are performed to validate the accuracy of the method and its application to low and high porosity materials. Also, it is shown that the "missing mass" method can be used to accurately evaluate the air density without the knowledge of the atmospheric conditions (temperature, static pressure, and relative humidity). © S. Hirzel Verlag. | |||||
BibTeX:
@article{Panneton2005342, author = {Panneton, R. and Gros, E.}, title = {A missing mass method to measure the open porosity of porous solids}, journal = {Acta Acustica united with Acustica}, year = {2005}, volume = {91}, number = {2}, pages = {342-348}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-17044385042&partnerID=40&md5=818759c130167969891abcf20bfa6151} } |
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Quaegebeur, N. and Chaigne, A. | Influence of material and shape on sound reproduction by an electrodynamic loudspeaker | 2005 | Audio Engineering Society - 118th Convention Spring Preprints 2005 Vol. 1, pp. 299-303 |
conference | URL |
Abstract: A key point in electroacoustics is to determine the transfer function between an input electrical signal and the radiated sound pressure. Since electrodynamic transducers radiate in a large frequency range, lumped parameter models are usually not sufficient to provide a realistic simulation of the vibroacoustical behavior of the system. In this paper, preliminary results on the use of modal equations for predicting the time domain sound field in free space radiated by a spherical shell in the audible range are presented. | |||||
BibTeX:
@conference{Quaegebeur2005299, author = {Quaegebeur, N. and Chaigne, A.}, title = {Influence of material and shape on sound reproduction by an electrodynamic loudspeaker}, journal = {Audio Engineering Society - 118th Convention Spring Preprints 2005}, year = {2005}, volume = {1}, pages = {299-303}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866504522&partnerID=40&md5=0de6fdb9cb4f76bae66b290600d7a82d} } |
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Richard, S. and Champoux, Y. | Evaluation of road bike comfort using classical and operational modal analyses | 2005 | Conference Proceedings of the Society for Experimental Mechanics Series | conference | URL |
Abstract: In the popular literature of the cycling world, comfort is one of the most frequently encountered words. This is also true for discussions among cyclists, especially long distance riders (100 km and more). The problem is that everybody talks about comfort, but nobody knows technically what actually creates comfort or discomfort on a road bike. This paper presents the results of the analyses performed to characterize the dynamic behavior of a road bike. Classical modal analysis, Operational Modal Analysis and Operating Deflection Shape are presented and compared. | |||||
BibTeX:
@conference{Richard2005, author = {Richard, S. and Champoux, Y.}, title = {Evaluation of road bike comfort using classical and operational modal analyses}, journal = {Conference Proceedings of the Society for Experimental Mechanics Series}, year = {2005}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861536345&partnerID=40&md5=03b1674c34dead8ed50b57d83d4eacb2} } |
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Sgard, F., Amirouche, N., Olny, X. and Atalla, N. | On the effect of a flexible support on the acoustic performances of meso-perforated materials | 2005 | 12th International Congress on Sound and Vibration 2005, ICSV 2005 Vol. 1, pp. 252-259 |
conference | URL |
Abstract: Passive devices are commonly used to control noise occurring in the fields of transportation, machinery equipments and buildings. Many kinds of porous materials are available on the market but due to their different microstructures, large differences can be observed in their absorption performance. Currently, it is difficult to adjust their microscopic geometry to optimize their performances or obtain specific absorption spectrum especially at low frequencies. Recently, the present authors have demonstrated that the concept of meso-perforations in appropriately chosen porous media could help enhance significantly their normal incidence sound absorption performance in a predefined frequency band. These meso-perforated materials are also referred to as "double porosity materials". Up to now, the authors have studied both numerically and experimentally the normal incidence sound absorption of these materials when they are bonded onto a rigid termination. However, in practice, the porous material is usually attached to a vibrating support. The objective of the paper is to investigate the effect of a flexible support on the sound performance of double porosity materials. The double porosity material is coupled to a flexible plate and excited by a normal incidence plane wave into a waveguide. The problem is solved using a finite element formulation for the different components and a modal approach for the sound propagation in the waveguide. Numerical results are presented regarding the effect of the supporting plate vibrations on the normal incidence sound absorption and transmission loss of selected double porosity materials. | |||||
BibTeX:
@conference{Sgard2005252, author = {Sgard, F. and Amirouche, N. and Olny, X. and Atalla, N.}, title = {On the effect of a flexible support on the acoustic performances of meso-perforated materials}, journal = {12th International Congress on Sound and Vibration 2005, ICSV 2005}, year = {2005}, volume = {1}, pages = {252-259}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881602320&partnerID=40&md5=0b13ef5906a65645cff28cc0c837da2e} } |
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Sgard, F., Olny, X., Atalla, N. and Castel, F. | On the use of perforations to improve the sound absorption of porous materials | 2005 | Applied Acoustics Vol. 66(6), pp. 625-651 |
article | DOI URL |
Abstract: The concept of meso-perforations in appropriately chosen porous media can help enhance their sound absorption performance. The meso-perforated materials are also referred to as "double porosity materials" since they are made up of two interconnected networks of pores of different characteristic size. Several theoretical, numerical and experimental works have been accomplished on the subject by the authors. The purpose of this paper is to give a synthetic review of these works and establish practical design rules to develop optimized noise control solutions based on this concept. The paper presents two complementary models to deal with this kind of materials: an analytical model based on homogenization techniques and a numerical model relying on a finite element discretization of the domains. The limits of these models are discussed. The choice of the design parameters is then been investigated in order to provide practical design rules. This choice relies on a criterion which is evaluated from the knowledge of the resistivity, porosity and tortuosity of the micropous medium, and the calculation of a geometrical parameter defined from the chosen mesoscopic structure. Experimental and numerical results regarding the influence of the mesopore profile along the thickness performed in a appropriately chosen substrate microporous medium are presented. The agreement between the models and the experiments is satisfactory. Results show that significant enhancements of the absorption properties can be obtained over a selected frequency band by adjusting the mesopore profile. It is also shown that interesting absorbing properties can be obtained when coating a double porosity medium with an impervious screen. © 2004 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Sgard2005625, author = {Sgard, F.C. and Olny, X. and Atalla, N. and Castel, F.}, title = {On the use of perforations to improve the sound absorption of porous materials}, journal = {Applied Acoustics}, year = {2005}, volume = {66}, number = {6}, pages = {625-651}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-13444249897&doi=10.1016%2fj.apacoust.2004.09.008&partnerID=40&md5=e4fdcf7dfdd10bf5db7a1218b563e733}, doi = {https://doi.org/10.1016/j.apacoust.2004.09.008} } |
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Wojtowicki, J.-L. and Panneton, R. | Improving the efficiency of sealing parts for hollow body network | 2005 | SAE Technical Papers | article | DOI URL |
Abstract: Nowadays, expanding sealing parts in automotive hollow body networks are widely used. These parts are usually made up from expanding foams or an assembly of expanding foams and solid materials. The use of these sealing parts has demonstrated an influence on the noise inside the car. These findings proved the necessity of designing sealing parts especially to reduce the propagation of sound through the frame cavities and hollow bodies. In this work, experimental investigations have been conducted to characterize the acoustic performances (absorption, transmission loss) of the individual materials constituting the parts and their assembly. Some design rules have been extracted to improve their efficiencies. Also, to better understand the acoustic behavior of the expanding foams, existing theoretical models for closed or open foams have been tested and compared to measurements. The comparisons showed the importance of accounting for the resonant and non-resonant surface absorption of these closed-cell foams. A simplified modeling of the expanding foam consisting of an elastic core surrounded by a resistive layer is proposed and compared to measurements. Copyright © 2005 SAE International. | |||||
BibTeX:
@article{Wojtowicki2005, author = {Wojtowicki, J.-L. and Panneton, R.}, title = {Improving the efficiency of sealing parts for hollow body network}, journal = {SAE Technical Papers}, year = {2005}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874843744&doi=10.4271%2f2005-01-2279&partnerID=40&md5=2f450db1cce3fe938f2ac55a03bd5a0d}, doi = {https://doi.org/10.4271/2005-01-2279} } |
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Audrain, P., Masson, P., Berry, A., Pascal, J.-C. and Gazengel, B. | The use of PVDF strain sensing in active control of structural intensity in beams | 2004 | Journal of Intelligent Material Systems and Structures Vol. 15(5), pp. 319-327 |
article | DOI URL |
Abstract: An investigation of structural intensity control associated with flexural vibration in beams using strain sensing is presented in this paper. The instantaneous intensity is completely taken into account in the control algorithm, i.e., all the terms are considered in the real-time control process and, in particular, the evanescent waves are considered in this approach. Previous work has shown the validity of the approach using an array of accelerometers to measure structural intensity. It is the purpose of this paper to present results on the use of strain sensing in the control of structural intensity. A finite difference approach using discrete PVDF strain sensors provides the structural intensity sensing scheme. A feedforward filtered-X LMS algorithm is adapted to this energy-based control problem, involving a nonpositive definite quadratic form in general. In this respect, the approach is limited to cases where the geometry is such that the intensity component will have the same sign for the control source and the primary disturbance. Experimental validation of the approach is conducted on a free-free beam covered with viscoelastic material and excited harmonically by a shaker. A comparison is made between classical acceleration control and structural intensity control and the performance of both approaches is presented. These results tend to indicate that intensity control allows the error sensors to be placed closer to the control source and the primary disturbance, while preserving a good control performance. | |||||
BibTeX:
@article{Audrain2004319, author = {Audrain, P. and Masson, P. and Berry, A. and Pascal, J.-C. and Gazengel, B.}, title = {The use of PVDF strain sensing in active control of structural intensity in beams}, journal = {Journal of Intelligent Material Systems and Structures}, year = {2004}, volume = {15}, number = {5}, pages = {319-327}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2442710579&doi=10.1177%2f1045389X04039936&partnerID=40&md5=e5161d6bb16469af62e89c5d8d81056d}, doi = {https://doi.org/10.1177/1045389X04039936} } |
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Buaka, P., Masson, P. and Micheau, P. | Experimental validation of a semi-active friction control device | 2004 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 5390, pp. 347-358 |
conference | DOI URL |
Abstract: In this paper, the experimental validation of a semi-active vibration reduction strategy is presented where energy is dissipated by dry friction contact surfaces. The aim of this project is to develop a semi-active friction compact device which can be bonded to any light flexible structure. The prototype presented in this paper incorporates two piezoelectric stack actuators used to apply a normal force between a mobile inertial component and two friction pads. This force is controlled so that the distance between the two surfaces is neither too small (to avoid shock and stiction that can cancel the slip between the two surfaces and then the friction effect) or too large (loss of contact surfaces). In order to avoid spillover effects found with the nonlinear control law leading to a bang-bang control, a lead-phase strategy is proposed for the controller. The friction model that was used to develop the controller is first introduced. The parameters of these models are determined experimentally and the friction force obtained from the model is compared with experimental measurements of this force. The piezoelectric stack actuator is then characterized with respect to the friction force generated. The friction model is then used to predict the controller performance for energy dissipation. The implementation of the controller is presented, together with the strategy adopted for the adjustment of the parameters of the controller. Control experiments are conducted on the prototype device and experimental results are presented to assess the performance of the controller. | |||||
BibTeX:
@conference{Buaka2004347, author = {Buaka, P. and Masson, P. and Micheau, P.}, title = {Experimental validation of a semi-active friction control device}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2004}, volume = {5390}, pages = {347-358}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-10044222168&doi=10.1117%2f12.540118&partnerID=40&md5=c6eb3e312805a47b28f867356edcb426}, doi = {https://doi.org/10.1117/12.540118} } |
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Champoux, Y., Vittecoq, P., Maltais, P., Auger, E. and Gauthier, B. | Measuring the dynamic structural load of an off-road bicycle frame | 2004 | Experimental Techniques Vol. 28(3), pp. 33-36 |
article | DOI URL |
Abstract: Knowledge about the loads carried by off-road bikes provides crucial information to bike frame manufacturers, allowing them to develop and propose new and optimized versions of their product. However, measuring loads in situ is a difficult task. In overcoming this challenge, the fully-instrumented bike is used for the measurements. | |||||
BibTeX:
@article{Champoux200433, author = {Champoux, Y. and Vittecoq, P. and Maltais, P. and Auger, E. and Gauthier, B.}, title = {Measuring the dynamic structural load of an off-road bicycle frame}, journal = {Experimental Techniques}, year = {2004}, volume = {28}, number = {3}, pages = {33-36}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2942555609&doi=10.1111%2fj.1747-1567.2004.tb00161.x&partnerID=40&md5=45d0c3f0625bfc37bbdcf67a1c669d24}, doi = {https://doi.org/10.1111/j.1747-1567.2004.tb00161.x} } |
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Côté, F., Masson, P., Mrad, N. and Cotoni, V. | Dynamic and static modelling of piezoelectric composite structures using a thermal analogy with MSC/NASTRAN | 2004 | Composite Structures Vol. 65(3-4), pp. 471-484 |
article | DOI URL |
Abstract: As a first step towards the development of simplified integrated computational tools for the dynamic and static modelling of smart structures, this work validates both theoretically and experimentally the implementation of a multilayered three-dimensional model based on the analogy between thermal strains and piezoelectric strains under MSC/NASTRAN. To assess the piezoelectric-thermal analogy for different loading conditions, the numerical results obtained from this model are first compared to the results obtained from a finite element reference model based on a three-dimensional piezoelectric formulation. An experimental assessment is also conducted on a clamped AS4/3501-6 carbon/epoxy composite beam structure excited in the vicinity of the clamped end using an embedded piezoelectric actuator. Results obtained from the dynamic response of the structure show that the properties of the insulating layer appear to have an important effect and thus demonstrate the need for their modelling. In the last part of the paper, as a tool for further development of the computational tools for smart structures, the piezoelectric-thermal analogy model is used with a large number of three-dimensional elements to describe the complexity of the strain and stress fields in the vicinity of the active region. © 2004 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Côté2004471, author = {Côté, F. and Masson, P. and Mrad, N. and Cotoni, V.}, title = {Dynamic and static modelling of piezoelectric composite structures using a thermal analogy with MSC/NASTRAN}, journal = {Composite Structures}, year = {2004}, volume = {65}, number = {3-4}, pages = {471-484}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18344398634&doi=10.1016%2fj.compstruct.2003.12.008&partnerID=40&md5=017c139d48eca0fc56b10747861ddcb7}, doi = {https://doi.org/10.1016/j.compstruct.2003.12.008} } |
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Gérard, A., Berry, A., Masson, P., Tartarin, J. and Gervais, Y. | An inverse aeroacoustic model for fans | 2004 | Collection of Technical Papers - 10th AIAA/CEAS Aeroacoustics Conference Vol. 3, pp. 2685-2693 |
conference | URL |
Abstract: An inverse aeroacoustic model for subsonic axial flow fans is proposed. The model aims at determining the circumferential blade loading variations (responsible for tonal sound radiation) from far-field acoustical measurements. The direct model is based on the Helmholtz integral equation, as formulated by Morse & Ingard. The inversion of the direct problem is mathematically ill-posed, and this problem is overcome by the Thikonov regularisation technique to improve the accuracy of the source strength reconstruction. A sensitivity analysis is first presented to show the influence of the regularisation parameter choice, signal to noise ratio and frequency. In this paper, simulations show that the loading harmonics can be partially reconstructed. Experimental results also demonstrate the ability of the inverse model to locate hot spots of rotor/stator interaction. Copyright © 2004 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. | |||||
BibTeX:
@conference{Gérard20042685, author = {Gérard, A. and Berry, A. and Masson, P. and Tartarin, J. and Gervais, Y.}, title = {An inverse aeroacoustic model for fans}, journal = {Collection of Technical Papers - 10th AIAA/CEAS Aeroacoustics Conference}, year = {2004}, volume = {3}, pages = {2685-2693}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-19944386254&partnerID=40&md5=a47de664c056631a6c472dbde1035f65} } |
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Ghinet, S., Atalla, N. and Osman, H. | Wave propagation in curved laminate composite structures | 2004 | Canadian Acoustics - Acoustique Canadienne Vol. 32(3), pp. 162-163 |
article | URL |
Abstract: A model to compute the transmission loss of the sandwich and laminate composite curved panels was developed. The physical behaviour of the panel was represented using a discrete lamina description and each lamina was represented by membrane, bending, transversal shearing and rotational inertial behaviour. The model density, the radiation efficiency and the resononant and non-resonant transmission loss were calculted by using the dispersion relation's solution. It was observed that for the presented problem, the modal energy exchange was dominated by the first wave solution. The result shows that for acoustic trasmission problems, the SEA scheme is accurate. | |||||
BibTeX:
@article{Ghinet2004162, author = {Ghinet, S. and Atalla, N. and Osman, H.}, title = {Wave propagation in curved laminate composite structures}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2004}, volume = {32}, number = {3}, pages = {162-163}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044249564&partnerID=40&md5=9b5a3f9aa67a0b67af3351b37ddd0845} } |
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Gros, E. and Panneton, R. | A missing mass method to measure the open porosity of porous solids | 2004 | Canadian Acoustics - Acoustique Canadienne Vol. 32(3), pp. 20-21 |
article | URL |
Abstract: A non limitative method is discussed to evaluate the open porosity of air-saturated porous materials. The proposed method deduces the open porosity through the experimental determination of the volume of the solid phase of a porous aggregate. The proposed missing mass method time efficient and does not assume isothermal conditions for the test. The results show that the last three meters can be eliminated if the ambient air density is measured using the missing mass as per the first test. | |||||
BibTeX:
@article{Gros200420, author = {Gros, E. and Panneton, R.}, title = {A missing mass method to measure the open porosity of porous solids}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2004}, volume = {32}, number = {3}, pages = {20-21}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044229788&partnerID=40&md5=95a943fa37fd503b2f78b9e71ce891b5} } |
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Micheau, P., Chatellier, L., Laumonier, J. and Gervais, Y. | Active control of a self-sustained pressure fluctuation due to flow over a cavityz | 2004 | Collection of Technical Papers - 10th AIAA/CEAS Aeroacoustics Conference Vol. 1, pp. 602-614 |
conference | URL |
Abstract: The problem addressed in this paper is to control the self-sustained pressure fluctuations due to flow over a cavity. The vortex sound theory describes how sound can be induced by periodic shedding of discrete vortices at the leading edge and their interaction with the downstream edge after convection across the cavity. The pressure sound generated by the vortex-edge interaction propagates upstream and trigger the vortex shedding upstream of the leading edge. An active device can act on this feedback loop in order to break the reinforcement mechanism, and thus to attenuate the self-sustained pressure fluctuations. The main originality of the presented active device is to use a vibrating surface located at the trailing edge in order to control the volume velocity generated by the interaction of vortex with the wall. The command of the vibrating surface is synchronized with the pressure fluctuations measured at the bottom of the cavity with a microphone. The describing function analysis is used to predict the self-sustained sinusoidal pressure and to explain the action of the active device on the feedback loop. Experimental data were obtained using the system in the test section of an Eiffel type wind-tunnel. The pressure fluctuation spectrum measured in the cavity without and with active control show an attenuation of 20 dB. Copyright © 2004 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. | |||||
BibTeX:
@conference{Micheau2004602, author = {Micheau, P. and Chatellier, L. and Laumonier, J. and Gervais, Y.}, title = {Active control of a self-sustained pressure fluctuation due to flow over a cavityz}, journal = {Collection of Technical Papers - 10th AIAA/CEAS Aeroacoustics Conference}, year = {2004}, volume = {1}, pages = {602-614}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-19644387905&partnerID=40&md5=b189f5d3a7c0edf87806e495a189362d} } |
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Oddo, R., Loyau, T., Boileau, P. and Champoux, Y. | Design of a suspended handle to attenuate rock drill hand-arm vibration: Model development and validation | 2004 | Journal of Sound and Vibration Vol. 275(3-5), pp. 623-640 |
article | DOI URL |
Abstract: The development of a suspended handle designed to provide attenuation of the vibration and shocks being generated at the tool blow frequency was carried out. The results of the first phase of development of such a handle were based on the development and validation of a model combining the suspended handle and the hand-arm system. It was found that the hand have a significant influence on the vibration transmissibility responses of the suspended handles. It was observed that when the resonant frequency of the free suspended handle was set at a higher frequency, the hand-arm system was found to provide additional damping at the handle resonant frequency. | |||||
BibTeX:
@article{Oddo2004623, author = {Oddo, R. and Loyau, T. and Boileau, P.E. and Champoux, Y.}, title = {Design of a suspended handle to attenuate rock drill hand-arm vibration: Model development and validation}, journal = {Journal of Sound and Vibration}, year = {2004}, volume = {275}, number = {3-5}, pages = {623-640}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-3042658760&doi=10.1016%2fj.jsv.2003.06.006&partnerID=40&md5=8500f6b179d50bcb75e301291f13e522}, doi = {https://doi.org/10.1016/j.jsv.2003.06.006} } |
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Osman, H., Atalla, N. and Ghinet, S. | Transmission loss testing and analysis of a curved sandwich composite panel | 2004 | Collection of Technical Papers - 10th AIAA/CEAS Aeroacoustics Conference Vol. 1, pp. 257-265 |
conference | URL |
Abstract: Prediction of the transmission loss of singly curved sandwich composite panels is presented for a special class of symmetric construction. Measurements of the transmission loss for such a panel are presented and compared to the predictions. Additional results for the panel covered with acoustic absorbing foams are presented and compared to predictions. The foam addition increases the panel apparent damping, and results in a larger increase of transmission loss than can be attributable to the added mass. It is concluded that the model accurately predicts the transmission loss and other acoustic properties. It can be employed for the acoustic design of such panels. Copyright © 2004 by The Boeing Company. | |||||
BibTeX:
@conference{Osman2004257, author = {Osman, H. and Atalla, N. and Ghinet, S.}, title = {Transmission loss testing and analysis of a curved sandwich composite panel}, journal = {Collection of Technical Papers - 10th AIAA/CEAS Aeroacoustics Conference}, year = {2004}, volume = {1}, pages = {257-265}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-19644373954&partnerID=40&md5=986bfb4a6a737947d9888c8bc8794985} } |
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Pasco, Y. and Berry, A. | A hybrid analytical/numerical model of piezoelectric stack actuators using a macroscopic nonlinear theory of ferroelectricity and a Preisach model of hysteresis | 2004 | Journal of Intelligent Material Systems and Structures Vol. 15(5), pp. 375-386 |
article | DOI URL |
Abstract: Hysteretic behavior of polarized piezoelectric materials is of importance in the context of high power electro-mechanical transduction. The main goal of this article is to combine the Tiersten theory of electroelasticity and a Preisach model of hysteresis to model a simple force loaded piezoelectric actuator. The proposed theory of piezo-ferro-elasticity extends the derivation of Tiersten and Huang to the case of an arbitrary polarization direction in the ferroelectric domain. The general model is subsequently reduced to a mono-dimensional stack actuator under low operating voltage; therefore, the modeling focuses on minor loop modeling around the initial state of polarization. The model of hysteresis between polarization and electric field proposed here takes into account the nonlocal (macroscopic) memory of a piezoelectric ceramic by the use of a Preisach model. The Preisach model of hysteresis and the set of new ferro-electro-elastic constants that account for the irreversible relation between electric field and polarization are identified through experiments. The nonlinear model successfully reproduces the nonlinear dependence of generated displacements and forces as a function of applied electric field. Possible applications of this work involve nonlinear actuator behavior in the active control of vibration. | |||||
BibTeX:
@article{Pasco2004375, author = {Pasco, Y. and Berry, A.}, title = {A hybrid analytical/numerical model of piezoelectric stack actuators using a macroscopic nonlinear theory of ferroelectricity and a Preisach model of hysteresis}, journal = {Journal of Intelligent Material Systems and Structures}, year = {2004}, volume = {15}, number = {5}, pages = {375-386}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2442666866&doi=10.1177%2f1045389X04040907&partnerID=40&md5=51db30d644f67080d8ec498575bc0b78}, doi = {https://doi.org/10.1177/1045389X04040907} } |
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Perrot, C., Panneton, R. and Olny, X. | From microstructure to acoustic behaviour of porous materials | 2004 | Canadian Acoustics - Acoustique Canadienne Vol. 32(3), pp. 18-19 |
article | URL |
Abstract: A method to determine the macroscopic parameters of absorbent materials from the knowledge of their cellular microstructure, either identified by computer microtomography or scaled by macro-micro geometrical model is discussed. All the relevant quantities have been computed on cellular systems. Study of the fluid velocity field for a hexagonal porous system reveal significant quantitative agreement between macroscopic parameters derived and measured from real aluminum foam. The results reveal the deep relationship between Kelvin structure and real reticulated foams. | |||||
BibTeX:
@article{Perrot200418, author = {Perrot, C. and Panneton, R. and Olny, X.}, title = {From microstructure to acoustic behaviour of porous materials}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2004}, volume = {32}, number = {3}, pages = {18-19}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044255041&partnerID=40&md5=a399d4681de85fda9715ef3e6d019e10} } |
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Pilon, D., Panneton, R., Sgard, F. and Lefebvre, L.-P. | Influence of micro-structural properties on the acoustic performances of novel metallic foams | 2004 | Canadian Acoustics - Acoustique Canadienne Vol. 32(3), pp. 24-25 |
article | URL |
Abstract: The links between the microstructural properties of the metal foams and their acoustic properties were investigated. The influence of the microstructural properties on the acoustic performances was also investigated. It was shown that a direct link exists between the thermal characteristic length of the Johnson-Champoux-Allard model and the average pore diameter in the studied open-cell metallic foams. The results show that the smart design of acoustical materials can be deemed attainable with these new materials. | |||||
BibTeX:
@article{Pilon200424, author = {Pilon, D. and Panneton, R. and Sgard, F. and Lefebvre, L.-P.}, title = {Influence of micro-structural properties on the acoustic performances of novel metallic foams}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2004}, volume = {32}, number = {3}, pages = {24-25}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044271071&partnerID=40&md5=7f3d2c54f4238b6e05be84743f347280} } |
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Pilon, D., Panneton, R. and Sgard, F. | Behavioral criterion quantifying the effects of circumferential air gaps on porous materials in the standing wave tube | 2004 | Journal of the Acoustical Society of America Vol. 116(1), pp. 344-356 |
article | DOI URL |
Abstract: The influence of mounting conditions on the measurement of the absorption coefficient in the standing wave tube (swt) is investigated. In a previous paper [D. Pilon, R. Panneton, and F. Sgard, J. Acoust. Soc. Am. 114, 1980-1987 (2003)], a behavioral criterion was developed to access the effect of a circumferential edge constraint on elastic foams. Similarly, the effect of circumferential air gaps on porous materials is studied here. The objective is to identify the materials, in terms of a ratio based on their physical properties, for which it is possible to measure the theoretical absorption coefficient when mounted inside the swt with a circumferential air gap. The difference between the measured and theoretical absorption coefficient is evaluated for a wide range of materials with various sample sizes. These errors are then sorted in terms of the chosen ratio. It is shown that for certain values of the ratio, the theoretical absorption coefficient can be efficiently measured using the swt. Through the use of this acousto-visco-inertial criterion, an experimenter can determine which absorption is going to be measured: the theoretical absorption or one that will be influenced by the circumferential air gaps. © 2004 Acoustical Society of America. | |||||
BibTeX:
@article{Pilon2004344, author = {Pilon, D. and Panneton, R. and Sgard, F.}, title = {Behavioral criterion quantifying the effects of circumferential air gaps on porous materials in the standing wave tube}, journal = {Journal of the Acoustical Society of America}, year = {2004}, volume = {116}, number = {1}, pages = {344-356}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-3142717530&doi=10.1121%2f1.1756611&partnerID=40&md5=5772f01684084f0b5b269c5774dcc9e0}, doi = {https://doi.org/10.1121/1.1756611} } |
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Rigobert, S., Sgard, F. and Atalla, N. | A two-field hybrid formulation for multilayers involving poroelastic, acoustic, and elastic materials | 2004 | Journal of the Acoustical Society of America Vol. 115(6), pp. 2786-2797 |
article | DOI URL |
Abstract: Recently, an implementation of the mixed pressure displacement u,P formulation for poroelastic materials using the theory of hierarchical elements has been proposed. It has been shown that poroelastic hierarchical elements allow for an important reduction of the number of degrees of freedom required for the modeling of a porous material in three dimensions, compared to linear finite elements. In this paper, the coupling of a porous material modeled with hierarchical elements and an elastic domain modeled with finite elements or a fluid modeled with hierarchical elements is presented. Non-coincident meshes are assumed. Continuity of the fields is ensured by using a two-field hybrid formulation. The paper is organized as follows. The theory is first presented. The computation of fluid-structure coupling integrals over non-coincident meshes is then tackled. Numerical results are produced to show the accuracy and the performance of the proposed model for the modeling of an elastic-porous or a porous-fluid coupled system. Comparisons between numerical simulations and experiments are also presented in the case of a porous coated plate. © 2004 Acoustical Society of America. | |||||
BibTeX:
@article{Rigobert20042786, author = {Rigobert, S. and Sgard, F.C. and Atalla, N.}, title = {A two-field hybrid formulation for multilayers involving poroelastic, acoustic, and elastic materials}, journal = {Journal of the Acoustical Society of America}, year = {2004}, volume = {115}, number = {6}, pages = {2786-2797}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2942676657&doi=10.1121%2f1.1698758&partnerID=40&md5=e3468b5944d7390b6f9ba85ff39f9610}, doi = {https://doi.org/10.1121/1.1698758} } |
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Sgard, F. and Atalla, N. | Sound radiation from poroelastic materials | 2004 | Canadian Acoustics - Acoustique Canadienne Vol. 32(3), pp. 16-17 |
article | URL |
Abstract: An approach to predict the sound radiation of baffled poroelastic media including fluid loading effect is discussed. The problem has been solved using a mixed finite-element method (FEM)-boundary element method (BEM) approach. In this approach the fluid loading is accounted for using an admittance matrix and solid phase-interstitial pressure coupling terms. The method has been considered in the case of an acoustic excitation. The results show that the radiation of the porous medium into the semi infinite fluid amounts to an added admittance term onto the interface interstitial pressure degrees of freedom. | |||||
BibTeX:
@article{Sgard200416, author = {Sgard, F.C. and Atalla, N.}, title = {Sound radiation from poroelastic materials}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2004}, volume = {32}, number = {3}, pages = {16-17}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044249591&partnerID=40&md5=7b3f175221b10314c4fe6348e0c5e460} } |
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Wojtowicki, J.-L., Jaouen, L. and Panneton, R. | New approach for the measurement of damping properties of materials using the Oberst beam | 2004 | Review of Scientific Instruments Vol. 75(8), pp. 2569-2574 |
article | DOI URL |
Abstract: An alternative method, which was proposed for the measurement of damping properties of materials using the Oberst beam, was discussed. The classical cantilever Oberst beam was replaced by a double sized free-free beam excited in its center. The analysis was based on a frequency response function measured between the imposed velocity at the center and an arbitrary point on the beam. It was concluded that the young's modulus and structural damping coefficient of the material under test can be deduced using classical formulations of the ASTM E756 standard for typical materials or using a finite element model for more complex cases. | |||||
BibTeX:
@article{Wojtowicki20042569, author = {Wojtowicki, J.-L. and Jaouen, L. and Panneton, R.}, title = {New approach for the measurement of damping properties of materials using the Oberst beam}, journal = {Review of Scientific Instruments}, year = {2004}, volume = {75}, number = {8}, pages = {2569-2574}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-4944259693&doi=10.1063%2f1.1777382&partnerID=40&md5=3b225e4490d8a4a301e4f56e53769364}, doi = {https://doi.org/10.1063/1.1777382} } |
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Atalla, N., Amédin, C. and Sgard, F. | Numerical and experimental investigation of the vibro-acoustics of a plate backed cavity coated with an heterogeneous porous material | 2003 | SAE Technical Papers | article | DOI URL |
Abstract: The design of multi-layer structures is of significant importance in several industries including automotive, aerospace and buildings. A typical application concerns a foam layer sandwiched between an elastic structure and a limp impervious layer classically known as a septum and coupled to an acoustic cavity. In designing these structures for various engineering applications, the engineer must select the type and mounting configurations of the foam attachment materials to be used. This task necessitates a thorough understanding of the mechanisms governing the acoustics and vibrations of such systems, together with an accurate data bank of the mechanical and acoustical properties of these materials. At low frequencies, where the modal behavior of the system is important, recent finite element prediction models based on Biot-Allard theory, have been developed [1, 2, 3 and 4]. Though accurate, the use of linear poroelastic elements based on the latter formulations leads to an important number of unknowns and thus requires important computational resources. Recently, an original implementation of the weak u,p formulation for porous materials using the theory of hierarchical elements has been presented [5]. The first objective of the paper is to investigate the validity of these implementations in the case of a plate coated with a porous material and coupled to a rigid walled cavity. Next the paper investigates the effect of insertion of air pocket and rigid masses in the foam on the response of the system. The numerical model is based on a finite element formulation for the different components. The coupling between the inclusions and the porous domain is accounted for naturally through the use of appropriate Biot's formulations. A power balance is also presented to study the effects of the different damping mechanisms in the system. A numerical example is presented regarding the effect of such inclusions on the vibration and acoustic of the studied system. Finally, experimental data are presented to support the modeling strategy and confirm the performance of the resulting heterogeneous materials. Copyright © 2003 SAE International. | |||||
BibTeX:
@article{Atalla2003, author = {Atalla, N. and Amédin, C.K. and Sgard, F.}, title = {Numerical and experimental investigation of the vibro-acoustics of a plate backed cavity coated with an heterogeneous porous material}, journal = {SAE Technical Papers}, year = {2003}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877387648&doi=10.4271%2f2003-01-1453&partnerID=40&md5=c7b8878b07ba3ea319e23878ca6f0bf1}, doi = {https://doi.org/10.4271/2003-01-1453} } |
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Atalla, N., Amédin, C., Atalla, Y., Sgard, F. and Osman, H. | Numerical modeling and experimental investigation of the absorption and transmission loss of heterogeneous porous materials | 2003 | Proceedings of the Tenth International Congress on Sound and Vibration, pp. 4673-4680 | conference | URL |
Abstract: The paper discusses both numerically and experimentally the low frequency vibro-acoustic response of macro-heterogeneous foams. The studied materials are made up of porous elastic materials containing fluid and/or solid inclusions. The coupling between the solid and the porous patches is accounted for naturally through the use of a modified u,p formulation. A power balance is also presented to study the effects of the different damping mechanisms in the system. As an example, the presented formulation is used to study the effects of insertion of rigid masses in the foam on the response of a plate-foam-cavity system. More experimental tests (absorption, TL, panel-cavity) and simulations will be discussed in the oral presentations. | |||||
BibTeX:
@conference{Atalla20034673, author = {Atalla, N. and Amédin, C.K. and Atalla, Y. and Sgard, F. and Osman, H.}, title = {Numerical modeling and experimental investigation of the absorption and transmission loss of heterogeneous porous materials}, journal = {Proceedings of the Tenth International Congress on Sound and Vibration}, year = {2003}, pages = {4673-4680}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2342423483&partnerID=40&md5=3781e86e2ffddbe573ddd50308208b2f} } |
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Buaka, P., Masson, P. and Micheau, P. | Development of a semi-active friction device to reduce vibration by energy dissipation | 2003 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 5056, pp. 603-614 |
conference | DOI URL |
Abstract: Aerospace structures such as antennas and solar panels often consist of truss elements which are connected by bolted joints. Friction damping in these bolted joint connections structures has been identified as a major source of damping. It has been proposed that an improvement in vibration reduction could be obtained by controlling the normal contact force using integrated piezoelectric elements in order to maximize the energy dissipated at the interface between the connected parts. This paper presents analytical and experimental results in order to demonstrate the interest of implementing semi-active vibration reduction by dissipating energy through dry friction contact surfaces. This work fits within the scope of a research project aiming at the development of a semi-active compact piezoelectric friction device which can be bonded to any light structure. In this device, a moving component will rub on two friction surfaces and the normal force on friction surfaces will be controlled so that the distance between moving component and friction surfaces is neither too small (to avoid shock and stiction that cancel the slip between two surfaces and then friction effect) or too large (lose of contact surface). This device will then be positioned on the structure in order to allow the maximum energy dissipation by friction to reduce the vibrations of the structure. Such semi-active device will ensure stability of the control approach arid will avoid the spillover effect found with the active approach in addition to reduce energy consumption cost. In this paper, an analytical and experimental study is carried out on two beams assembled by a joint bolted to show the influence of the normal gripping force (tightening torque in this case), directly related to the friction force, on the damping of the modes. | |||||
BibTeX:
@conference{Buaka2003603, author = {Buaka, P. and Masson, P. and Micheau, P.}, title = {Development of a semi-active friction device to reduce vibration by energy dissipation}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2003}, volume = {5056}, pages = {603-614}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242443361&doi=10.1117%2f12.483479&partnerID=40&md5=a22d14edd1666d1179cb7059d0a524f5}, doi = {https://doi.org/10.1117/12.483479} } |
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Champoux, Y., Cotoni, V., Paillard, B. and Beslin, O. | Moment excitation of structures using two synchronized impact hammers | 2003 | Journal of Sound and Vibration Vol. 263(3), pp. 515-533 |
article | DOI URL |
Abstract: Moment mobilities are difficult to measure because there is no simple way to excite a structure with a well-controlled moment. In this paper, a technique to apply a nearly pure moment is presented. It is based on a simple approach that uses two impact forces applied, respectively, by two impact hammers. The limits and the validity of this approach are first examined theoretically on a simply supported plate. Comparisons between the excitation by two distant opposite forces and by a pure moment are performed. Then, the coupling between the two hammers and the structure during the impact phase is considered in order to analyze practical limits of obtaining identical forces impacting at different locations. Finally, a detailed description of the experimental system developed to obtain identical synchronized forces is presented. Two hammers driven by electric motors controlled by a Digital Signal Processor are used. Experimental results are compared to theoretical predictions. It is shown that the technique yields accurate measurements of moment frequency response functions. © 2002 Elsevier Science Ltd. All rights reserved. | |||||
BibTeX:
@article{Champoux2003515, author = {Champoux, Y. and Cotoni, V. and Paillard, B. and Beslin, O.}, title = {Moment excitation of structures using two synchronized impact hammers}, journal = {Journal of Sound and Vibration}, year = {2003}, volume = {263}, number = {3}, pages = {515-533}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038486189&doi=10.1016%2fS0022-460X%2802%2901064-7&partnerID=40&md5=1fe2865d76e377850dcd3aa05d7775d8}, doi = {https://doi.org/10.1016/S0022-460X(02)01064-7} } |
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Chiello, O., Sgard, F. and Atalla, N. | On the use of a component mode synthesis technique to investigate the effects of elastic boundary conditions on the transmission loss of baffled plates | 2003 | Computers and Structures Vol. 81(28-29), pp. 2645-2658 |
article | DOI URL |
Abstract: In this paper, it is shown that the structural and acoustic response of an elastically-supported baffled plate excited by a plane wave or a diffuse field can be solved efficiently using a free-interface component mode synthesis technique, in which the elastic support is considered as a mass-less structural component characterized solely by a flexibility matrix. The presented method is applied to the calculation of the transmission loss of plates with different boundary stiffness and is shown to be well adapted to parameter studies and optimization. The convergence of the technique is investigated and an example of parameter study is presented. © 2003 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{Chiello20032645, author = {Chiello, O. and Sgard, F.C. and Atalla, N.}, title = {On the use of a component mode synthesis technique to investigate the effects of elastic boundary conditions on the transmission loss of baffled plates}, journal = {Computers and Structures}, year = {2003}, volume = {81}, number = {28-29}, pages = {2645-2658}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0142106847&doi=10.1016%2fS0045-7949%2803%2900326-2&partnerID=40&md5=807832464822fb7da0a2f4e76784ed2a}, doi = {https://doi.org/10.1016/S0045-7949(03)00326-2} } |
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Dauchez, N., Sahraoui, S. and Atalla, N. | Investigation and modelling of damping in a plate with a bonded porous layer | 2003 | Journal of Sound and Vibration Vol. 265(2), pp. 437-449 |
article | DOI URL |
Abstract: Behavior of a poro-elastic material bonded onto a vibrating plate is investigated in the low-frequency range. From the analysis of dissipation mechanisms, a model accounting for damping added by the porous layer on the plate is derived. This analysis is based on a 3-D finite element formulation including poro-elastic elements based on Biot displacement theory. First, dissipated powers related to thermal, viscous and viscoelastic dissipation are explicited. Then a generic configuration (simply-supported aluminium plate with a bonded porous layer and mechanical excitation) is studied. Thermal dissipation is found negligible. Viscous dissipation can be optimized as a function of airflow resistivity. It can be the major phenomenon within soft materials, but for most foams viscoelastic dissipation is dominant. Consequently an equivalent plate model is proposed. It includes shear in the porous layer and only viscoelasticity of the skeleton. Excellent agreement is found with the full numerical model. © 2002 Elsevier Science Ltd. All rights reserved. | |||||
BibTeX:
@article{Dauchez2003437, author = {Dauchez, N. and Sahraoui, S. and Atalla, N.}, title = {Investigation and modelling of damping in a plate with a bonded porous layer}, journal = {Journal of Sound and Vibration}, year = {2003}, volume = {265}, number = {2}, pages = {437-449}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0042268568&doi=10.1016%2fS0022-460X%2802%2901454-2&partnerID=40&md5=535105ac1549d23d422425d2e9172208}, doi = {https://doi.org/10.1016/S0022-460X(02)01454-2} } |
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Jaouen, L., Atalla, N. and Brouard, B. | Modeling thin foam layer bonded onto a plate in the low frequency range | 2003 | Acta Acustica (Stuttgart) Vol. 89(SUPP.), pp. S96 |
article | URL |
Abstract: Multilayered structures including poro-elastic materials, like polymer foams, are widely used for sound absorption and vibrations damping in buildings and in the transport industries. Predictions of the mechanical behaviour of such structures are usually done with complete classical poro-elastic finite element models which lead to important computation time and memory usage. However, some practical configurations can be more easily described by making assumptions about the porous material behaviour. This paper presents a fast numerical model, based on a hierarchical trigonometric function set, to predict the mechanical behaviour of a metal plate backed by a foam. The plate is excited in bending vibration with a concentrated load over the approximate frequency range of 10-1000 Hz. The base layer can have any boundary conditions among the following: free, simply supported or clamped edge. The proposed model describes the elastic plate - porous layer system as an equivalent viscoelastic plate. Viscous effects in the porous media are taken into account through the effective density of Biot's theory. Comparisons with complete numerical and experimental data are presented to confirm the accuracy of the proposed model and define its range of validity. | |||||
BibTeX:
@article{Jaouen2003, author = {Jaouen, L. and Atalla, N. and Brouard, B.}, title = {Modeling thin foam layer bonded onto a plate in the low frequency range}, journal = {Acta Acustica (Stuttgart)}, year = {2003}, volume = {89}, number = {SUPP.}, pages = {S96}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038141870&partnerID=40&md5=e5521d4261a8643022816a6fe63106fe} } |
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Masson, P., Micheau, P., Delaunay, T. and Pinsonnault, J. | Signal processing strategies using micro-systems for in situ health monitoring of aircraft | 2003 | SAE Technical Papers | article | URL |
Abstract: This paper provides an overview of a recently started project aimed at reducing the high costs associated with periodic prescribed inspections of aircraft structures by the development of an in situ structural health monitoring (SHM) system. The development of the in situ monitoring system is based on the use of advanced sensing and actuating devices such as MEMS and functional materials. This paper highlights candidate signal processing strategies for health monitoring of aircraft structures. In this preliminary work, one of the candidate time-frequency approaches is presented: subband filtering or signal envelope processing. This strategy is implemented on a real-time rapid prototyping system and validated on a simplified aircraft component. Experimental results are presented and provide some indications on the appropriateness of this approach for health monitoring of structures. Copyright © 2003 SAE International. | |||||
BibTeX:
@article{Masson2003, author = {Masson, P. and Micheau, P. and Delaunay, T. and Pinsonnault, J.}, title = {Signal processing strategies using micro-systems for in situ health monitoring of aircraft}, journal = {SAE Technical Papers}, year = {2003}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877370900&partnerID=40&md5=6c09d3d00a8faad98f6595f1d7a37249} } |
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Micheau, P., Kron, A. and Bourassa, P. | Evaluation of the lambda model for human postural control during ankle strategy | 2003 | Biological Cybernetics Vol. 89(3), pp. 227-236 |
article | DOI URL |
Abstract: An accurate modeling of human stance might be helpful in assessing postural deficit. The objective of this article is to validate a mathematical postural control model for quiet standing posture. The postural dynamics is modeled in the sagittal plane as an inverted pendulum with torque applied at the ankle joint. The torque control system is represented by the physiological lambda model. Two neurophysiological command variables of the central nervous system, designated ? and µ, establish the dynamic threshold muscle at which moto-neuron recruitment begins. Kinematic data and electromyographic signals were collected on four young males in order to measure small voluntary sway and quiet standing posture. Validation of the mathematical model was achieved through comparison of the experimental and simulated results. The mathematical model allows computation of the unmeasurable neurophysiological commands ? and µ that control the equilibrium position and stability. Furthermore, with the model it is possible to conclude that low-amplitude body sway during quiet stance is commanded by the central nervous system. | |||||
BibTeX:
@article{Micheau2003227, author = {Micheau, P. and Kron, A. and Bourassa, P.}, title = {Evaluation of the lambda model for human postural control during ankle strategy}, journal = {Biological Cybernetics}, year = {2003}, volume = {89}, number = {3}, pages = {227-236}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0142071574&doi=10.1007%2fs00422-003-0412-z&partnerID=40&md5=9d264574587322bef4c1adbfc76d39e1}, doi = {https://doi.org/10.1007/s00422-003-0412-z} } |
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Nelisse, H., Onsay, T. and Atalla, N. | Structure borne insertion loss of sound package components | 2003 | SAE Technical Papers | article | DOI URL |
Abstract: Typical automotive sound package components are usually characterized by their absorption coefficients and their acoustic power-based insertion loss. This insertion loss (IL) is usually obtained by subtracting the transmission loss (TL) of a bare flat steel plate from the TL of the same plate covered with the trim material. While providing useful information regarding the performance of the component, air-borne insertion loss is based solely on acoustic excitations and thus provides very little information about the structure-borne performance of the component. This paper presents an attempt to introduce a standard procedure to define the power-based structure-borne insertion loss of sound package components. A flat steel plate is excited mechanically using a shaker. Different carpet constructions are applied on the plate and tested. Based on velocity measurements, a force transducer and intensity probe, the mechanical input and the acoustic radiated power are obtained. Structure-borne insertion loss is then calculated from the input and radiated power measurements. Details of the technique are described and results for different configurations are presented and discussed. In order to analyze the governing physical mechanisms, low and high frequency numerical simulations are studied. The numerical approach is based on two methods;1) the low frequency spectrum is covered using a finite element formulation,2) a transfer matrix approach, modified to incorporate mechanical excitations, is used for the high frequency portion of the spectrum. Copyright © 2003 SAE International. | |||||
BibTeX:
@article{Nelisse2003, author = {Nelisse, H. and Onsay, T. and Atalla, N.}, title = {Structure borne insertion loss of sound package components}, journal = {SAE Technical Papers}, year = {2003}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877378924&doi=10.4271%2f2003-01-1549&partnerID=40&md5=af842403d3fd2b87824450188e6b2085}, doi = {https://doi.org/10.4271/2003-01-1549} } |
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Osman, H., Atalla, N., Atalla, Y. and Panneton, R. | Effects of acoustic blankets on the insertion loss of a composite sandwich cylinder | 2003 | Proceedings of the Tenth International Congress on Sound and Vibration, pp. 2245-2252 | conference | URL |
Abstract: Composite sandwich cylinders are widely used in launch vehicles. Sound absorbing blankets are commonly employed to control the interior noise levels. The effects of blanket design on the insertion loss of such cylinders are investigated. The absorption and transmission loss performance of the packages is discussed. Experimental results show that low frequency absorption can be enhanced by certain multi-layered and macro-pores configurations. Transmission loss results are compared to analytical predictions based on TMM. Results of tests performed on a composite cylinder with the different trim packages are presented. Two types of foams; namely, melamine and polyimide, were tested in multiple configurations. It is concluded that macro perforated foam and other configurations improves the noise reduction. | |||||
BibTeX:
@conference{Osman20032245, author = {Osman, H. and Atalla, N. and Atalla, Y. and Panneton, R.}, title = {Effects of acoustic blankets on the insertion loss of a composite sandwich cylinder}, journal = {Proceedings of the Tenth International Congress on Sound and Vibration}, year = {2003}, pages = {2245-2252}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2342443332&partnerID=40&md5=feef794b59c8eaf37d86a5ecd3c1a4c1} } |
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Panneton, R., Atalla, Y., Blanchet, D. and Bloor, M. | Validation of the inverse method of acoustic material characterization | 2003 | SAE Technical Papers | article | DOI URL |
Abstract: There are many software tools in use today that are implementing the Biot, or complementary, method for the evaluation of foam and fiber materials. The justification of this process is to understand which mechanisms of the noise control material are contributing to the noise reduction and to optimize the material based on its acoustic properties. The disadvantage of this method is that it is quite complex and time consuming to test a material in order to extract the underlying properties that govern the acoustic performance. An alternative inverse method for material characterization based on simple impedance tube measurements has been developed lately. This paper recalls the physics and mathematics behind the method and concentrates on its validation. Copyright © 2003 SAE International. | |||||
BibTeX:
@article{Panneton2003, author = {Panneton, R. and Atalla, Y. and Blanchet, D. and Bloor, M.}, title = {Validation of the inverse method of acoustic material characterization}, journal = {SAE Technical Papers}, year = {2003}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877388975&doi=10.4271%2f2003-01-1584&partnerID=40&md5=31dc972b99ea667c087f772ea8681c12}, doi = {https://doi.org/10.4271/2003-01-1584} } |
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Pilon, D., Sgard, F. and Panneton, R. | Frame acoustical excitability: A decoupling criterion for poroelastic materials | 2003 | Acta Acustica (Stuttgart) Vol. 89(SUPP.), pp. S54-S55 |
article | URL |
Abstract: Above a certain frequency, a partial decoupling between the solid and fluid phases of an open-cell porous medium exists. An expression for this decoupling frequency was derived by Zwikker and Kosten. For most poroelastic materials, at frequencies higher than the latter, the visco-inertial coupling between the two phases is weak enough so that an acoustical wave propagating in the fluid phase will not exert a sufficient force to generate vibrations in the solid phase. This is not the case for all poroelastic materials as the 1/4 wavelength resonance frequency of the frame-borne wave will sometimes be apparent in the absorption coefficient, even if it is higher than the decoupling frequency. In this paper, a new decoupling criterion is presented. It is based on the frame acoustical excitability concept (FAE). The FAE is a measurement of the rate at which the acoustical energy is transferred from the air to the frame of a poroelastic material. A critical value of FAE, below which the solid and fluid phases are decoupled, is established. Through the use of this decoupling criterion, one can know if the 1/4 wavelength resonance frequency will be apparent or not in the absorption coefficient. | |||||
BibTeX:
@article{Pilon2003, author = {Pilon, D. and Sgard, F. and Panneton, R.}, title = {Frame acoustical excitability: A decoupling criterion for poroelastic materials}, journal = {Acta Acustica (Stuttgart)}, year = {2003}, volume = {89}, number = {SUPP.}, pages = {S54-S55}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038142199&partnerID=40&md5=4242cca01bed78fed05a342462ccd645} } |
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Pilon, D., Panneton, R. and Sgard, F. | Behavioral criterion quantifying the edge-constrained effects on foams in the standing wave tube | 2003 | Journal of the Acoustical Society of America Vol. 114(4 I), pp. 1980-1987 |
article | DOI URL |
Abstract: The influence of mounting conditions on the measurement of the sound absorption coefficient is investigated. More specifically, the effects of a circumferential edge constraint applied on elastic foams in a standing wave tube are studied. The objective is to identify the foams for which it is possible to measure the theoretical absorption coefficient using the tube. This identification relies on the evaluation of a new parameter, the Frame Acoustical Excitability (FAE), based on the foams' physical properties. In order to quantify the difference between the measured and theoretical absorptions, a linear correlation coefficient is evaluated for a wide range of foams with various sample sizes. The calculated correlation coefficients are then sorted in terms of the FAE. It is shown that as the value of FAE increases, the difference between the measured and theoretical absorption coefficients becomes more significant. A critical value of FAE, below which the theoretical absorption can be efficiently measured using the tube, is established. Through the use of this elasto-acoustic criterion, an experimenter can make an educated guess as to which absorption is measured with the tube: the theoretical absorption or one that is affected by either the edge constraint or the sample's dimensions. © 2003 Acoustical Society of America. | |||||
BibTeX:
@article{Pilon20031980, author = {Pilon, D. and Panneton, R. and Sgard, F.}, title = {Behavioral criterion quantifying the edge-constrained effects on foams in the standing wave tube}, journal = {Journal of the Acoustical Society of America}, year = {2003}, volume = {114}, number = {4 I}, pages = {1980-1987}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0142090039&doi=10.1121%2f1.1598193&partnerID=40&md5=b7cab2556e085838719a98798627f67b}, doi = {https://doi.org/10.1121/1.1598193} } |
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Rigobert, S., Atalla, N. and Sgard, F. | Investigation of the convergence of the mixed displacement-pressure formulation for three-dimensional poroelastic materials using hierarchical elements | 2003 | Journal of the Acoustical Society of America Vol. 114(5), pp. 2607-2617 |
article | DOI URL |
Abstract: Recently, a mixed pressure displacement u, P formulation based on Biot's poroelasticity equations has been presented for porous materials. This model leads to a reduction of the number of degrees of freedom required for the modeling of three-dimensional porous media in comparison to classical displacement-displacement u, U formulations. In this paper, an extension of the u, P formulation based on hierarchical elements is presented. First, a variant of the weak integral form of the u, P formulation is presented and its numerical implementation using hierarchical elements is detailed, together with the application of boundary and loading conditions. Numerical results are presented to show the accuracy and performance of the present approach. In particular, the importance of correctly capturing the coupling effects between the two phases is highlighted. © 2003 Acoustical Society of America. | |||||
BibTeX:
@article{Rigobert20032607, author = {Rigobert, S. and Atalla, N. and Sgard, F.C.}, title = {Investigation of the convergence of the mixed displacement-pressure formulation for three-dimensional poroelastic materials using hierarchical elements}, journal = {Journal of the Acoustical Society of America}, year = {2003}, volume = {114}, number = {5}, pages = {2607-2617}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242609112&doi=10.1121%2f1.1616579&partnerID=40&md5=1ad611f7b080135c139032f630df700e}, doi = {https://doi.org/10.1121/1.1616579} } |
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Sgard, F., Atalla, N. and Amedin, C. | Vibro-acoustic behavior of a plate coated with an heterogeneous porous material radiating in a rigid walled cavity | 2003 | Acta Acustica (Stuttgart) Vol. 89(SUPP.), pp. S55 |
article | URL |
Abstract: Today, the improvement of efficient acoustical absorbent devices at low frequencies for industries like transportation or buildings is of the utmost importance. Porous materials are commonly used in noise control solutions to reduce both structure and air-borne sound together with decrease resonant structural vibrations. Recently, new solutions based on the addition of inclusions or additives in matrix materials have been proposed to improve their acoustic absorption, acoustic attenuation and vibration damping properties (double porosity materials, hybrid materials made up of polymers with solid inclusions?). This paper investigates the influence of adding heterogeneities (macro solid pieces or air pockets) on the vibroacoustic behavior of a plate coated with a porous material radiating in a rigid walled cavity. The proposed numerical model is based on a finite element Biot-Allard's formulation for the porous patches and classical finite element formulation for the solid or fluid inclusions. The coupling between the inclusions (solid or acoustic) and the porous patches is accounted for naturally through the use of appropriate integral formulations of Biot's poroelasticity equations. Results are presented concerning the influence of several types of inclusions on the vibroacoustic performance of the plate lined with the heterogeneous porous material system. | |||||
BibTeX:
@article{Sgard2003, author = {Sgard, F. and Atalla, N. and Amedin, C.K.}, title = {Vibro-acoustic behavior of a plate coated with an heterogeneous porous material radiating in a rigid walled cavity}, journal = {Acta Acustica (Stuttgart)}, year = {2003}, volume = {89}, number = {SUPP.}, pages = {S55}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038142198&partnerID=40&md5=045be1dfba8bfc50bc21ab8a890789f0} } |
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Allard, J.-F., Henry, M., Tizianel, J., Nicolas, J. and Miki, Y. | Pole contribution to the field reflected by sand layers | 2002 | Journal of the Acoustical Society of America Vol. 111(2), pp. 685-689 |
article | DOI URL |
Abstract: Measurements of the reflection coefficient at oblique incidence and for inhomogeneous waves are presented for layers of sand having a large flow resistivity and different thicknesses. The dependence of the reflection coefficient on the angle of incidence is different for layers of small thickness and semi-infinite layers, due to the influence of a pole which is related to an ordinary guided wave in the first case, and the Zenneck wave in the second case. Simulations indicate that the amplitude of the Zenneck wave can be measured for small source receiver distances, allowing a simple evaluation in situ of the surface impedance. The same method can be used with the ordinary surface wave for thin layers. © 2002 Acoustical Society of America. | |||||
BibTeX:
@article{Allard2002685, author = {Allard, J.-F. and Henry, M. and Tizianel, J. and Nicolas, J. and Miki, Y.}, title = {Pole contribution to the field reflected by sand layers}, journal = {Journal of the Acoustical Society of America}, year = {2002}, volume = {111}, number = {2}, pages = {685-689}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036161169&doi=10.1121%2f1.1428283&partnerID=40&md5=f8837a372065cda0bc388d1e297aff3d}, doi = {https://doi.org/10.1121/1.1428283} } |
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Atalla, N., Amedin, C. and Osman, H. | Numerical and experimental investigation of the vibro-acoustics of a multilayered plate backed cavity | 2002 | 8th AIAA/CEAS Aeroacoustics Conference and Exhibit | conference | URL |
Abstract: The paper discusses both numerically and experimentally the vibro-acoustics of a plate-backed cavity with attached foam layer. Firstly, it investigates the modeling and behaviour of the panelfoam system. Secondly, it discusses the effects of adding a hard walled cavity. In particular, the effects of mounting, damping, films, and the accuracy of measurements of foam properties are discussed. Finally, the added damping brought in by the foam layer will be quantified and elucidated. © 2002 by the author(s). Published by the American Institute of Aeronautics and Astronautics, Inc. | |||||
BibTeX:
@conference{Atalla2002, author = {Atalla, N. and Amedin, C.K. and Osman, H.}, title = {Numerical and experimental investigation of the vibro-acoustics of a multilayered plate backed cavity}, journal = {8th AIAA/CEAS Aeroacoustics Conference and Exhibit}, year = {2002}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84896823780&partnerID=40&md5=901730967c022c668e7ea86b62dc71ba} } |
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Atalla, N., Panneton, R., Sgard, F. and Olny, X. | Erratum: Acoustic absorption of macro-perforated porous materials (Journal of Sound and Vibration (2001) 243 (659-678)) [BibTeX] |
2002 | Journal of Sound and Vibration Vol. 256(2), pp. 389 |
article | DOI URL |
BibTeX:
@article{Atalla2002389, author = {Atalla, N. and Panneton, R. and Sgard, F. and Olny, X.}, title = {Erratum: Acoustic absorption of macro-perforated porous materials (Journal of Sound and Vibration (2001) 243 (659-678))}, journal = {Journal of Sound and Vibration}, year = {2002}, volume = {256}, number = {2}, pages = {389}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037068910&doi=10.1006%2fjsvi.2002.5207&partnerID=40&md5=8766096fe5ed648738cddaedaeec7c4d}, doi = {https://doi.org/10.1006/jsvi.2002.5207} } |
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Brouillette, M., Nicolas, J., Charron, F. and Proulx, D. | The integrated mechanical engineering curriculum at the université de Sherbrooke | 2002 | ASEE Annual Conference Proceedings, pp. 2761-2772 | conference | URL |
Abstract: The integrated mechanical engineering curriculum at the Université de Sherbrooke is discussed. A competency-based approach is used to produce a closely integrated program. The details of the first semester to illustrate the mechanics of the curriculum are also presented. It is found that graduating engineers had knowledge but were dramatically lacking in know-how. | |||||
BibTeX:
@conference{Brouillette20022761, author = {Brouillette, M. and Nicolas, J. and Charron, F. and Proulx, D.}, title = {The integrated mechanical engineering curriculum at the université de Sherbrooke}, journal = {ASEE Annual Conference Proceedings}, year = {2002}, pages = {2761-2772}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-8744243238&partnerID=40&md5=43de8551b40d5634d7230d939e530b08} } |
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Castel, F., Sgard, F. and Atalla, N. | Quadratic finite element model for predicting the vibroacoustic behaviour of heterogeneous porous materials | 2002 | Proceedings of the 2002 International Conference on Noise and Vibration Engineering, ISMA, pp. 2207-2215 | conference | URL |
Abstract: Porous materials are widely used for noise and vibration control. Classical solutions involving fiber glass or foams are very common in buildings and in industries to reduce noise levels. However, it is necessary to make choices between possible alternatives during the design stage of a project according to efficiency, standards requirements and costs. In particular, weight is a major issue in aeronautics and automotive industries. Recently finite element models of heterogeneous porous materials using the (u,P) weak integral form of Biot's poro-elasticity equations have been developed. These works have shown that the addition of heterogeneities (solid inclusions, air pockets) could increase both the acoustic absorption and the transmission loss performances of porous materials. Nevertheless problems have been exhibited in the case of linear elements. Indeed these elements may suffer from convergence problems due to the strong variations of the fields close to the heterogeneities. This work presents a method to circumvent these issues. It consists in a quadratic finite element implementation of both the porous patches and the inclusions. Numerical results are presented which compare the performance of the proposed approach to the linear finite element implementation. Then, the developed method is applied to the prediction of the acoustic absorption and transmission of several systems involving heterogeneous porous materials. | |||||
BibTeX:
@conference{Castel20022207, author = {Castel, F. and Sgard, F. and Atalla, N.}, title = {Quadratic finite element model for predicting the vibroacoustic behaviour of heterogeneous porous materials}, journal = {Proceedings of the 2002 International Conference on Noise and Vibration Engineering, ISMA}, year = {2002}, pages = {2207-2215}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-13444278736&partnerID=40&md5=cae0ccac388c540aa6dbd54756f65b64} } |
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Côté, F., Masson, P. and Mrad, N. | Dynamic and static assessment of piezoelectric embedded composites | 2002 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 4701, pp. 316-325 |
conference | DOI URL |
Abstract: The design of fully integrated structures, and especially of new generation composites with embedded sensors and actuators, now requires the development of adequate tools for predicting the static and the dynamic behavior of the structure as well as its life cycle. These tools will provide flexibility in assessing well-suited control strategies for optimum structural performance. As a first step towards the development of integrated computational tools for smart structures, this work validates both theoretically and experimentally the implementation under MSC/NASTRAN of a simplified multilayer tri-dimensional model based on the analogy between thermal strains and piezoelectric strains. Numerical results obtained from this model are first compared to results obtained from a reference finite element tri-dimensional piezoelectric code developed to assess the thermal analogy for different loading conditions. Experimental validation is also conducted on a clamped AS4/3501-6 carbon/epoxy composite beam structure excited at the clamped end by an embedded piezoelectric. Results obtained from vibration testing are assessed with the thermal analogy model using a large number of tri-dimensional elements in order to get a detailed representation of the different variables. Details for practical implementation of the embedment procedures are presented along with the adequate model prediction of the structure's dynamic behavior. | |||||
BibTeX:
@conference{Côté2002316, author = {Côté, F. and Masson, P. and Mrad, N.}, title = {Dynamic and static assessment of piezoelectric embedded composites}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2002}, volume = {4701}, pages = {316-325}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036029237&doi=10.1117%2f12.474667&partnerID=40&md5=7be1fd726e0c82658b1c30ca5a180107}, doi = {https://doi.org/10.1117/12.474667} } |
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Dazel, O., Sgard, F., Lamarque, C.-H. and Atalla, N. | An extension of complex modes for the resolution of finite-element poroelastic problems | 2002 | Journal of Sound and Vibration Vol. 253(2), pp. 421-445 |
article | DOI URL |
Abstract: A new modal synthesis technique inspired from complex modes is presented in this paper. The purpose of this method is to find an alternative to the weakness of usual modal techniques in order to improve resolution of finite-element poroelastic problems. Firstly, the construction of modes and the synthesis for a general forcing is explained. Secondly, the approach is applied to a one-dimensional poroelastic problem. Finally, the approach is numerically tested and its performance is investigated by comparison with solutions obtained with a direct resolution of the system. | |||||
BibTeX:
@article{Dazel2002421, author = {Dazel, O. and Sgard, F. and Lamarque, C.-H. and Atalla, N.}, title = {An extension of complex modes for the resolution of finite-element poroelastic problems}, journal = {Journal of Sound and Vibration}, year = {2002}, volume = {253}, number = {2}, pages = {421-445}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037001687&doi=10.1006%2fjsvi.2001.4062&partnerID=40&md5=631c0af6805aaec587a6ff826d9c72ee}, doi = {https://doi.org/10.1006/jsvi.2001.4062} } |
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Ghinet, S. and Atalla, N. | Vibro-acoustic behaviour of multi-layer orthotropic panels | 2002 | Canadian Acoustics - Acoustique Canadienne Vol. 30(3), pp. 72-73 |
article | URL |
Abstract: Vibro-acoustic behavior of multi-layer orthotropic panels was discussed. A general eigenvalue approach based on wave theory was presented to compute the dispersion curves of panels. The radiation efficiency, the modal density and the group velocity were computed using these curves, and were used to predict the transmission loss of the panels. Results showed that at low frequencies the effect of bending dominates while at high frequencies shearing became significant. | |||||
BibTeX:
@article{Ghinet200272, author = {Ghinet, S. and Atalla, N.}, title = {Vibro-acoustic behaviour of multi-layer orthotropic panels}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2002}, volume = {30}, number = {3}, pages = {72-73}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036750273&partnerID=40&md5=db2739cc49ea3c3f2c7e07d072e6d6f1} } |
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Jaouen, L., Atalla, N. and Brouard, B. | A method for the inverse characterization of poroelastic mechanical properties | 2002 | Canadian Acoustics - Acoustique Canadienne Vol. 30(3), pp. 66-67 |
article | URL |
Abstract: A method for the inverse characterization of poroelastic mechanics was presented. The dependence of the natural frequencies of vibration of a poroelastic material bound onto an aluminium plate on the Young's modulus and structural loss factor was determined. An equivalent plate model was developed for the purpose, taking into account viscous effects and structural damping. | |||||
BibTeX:
@article{Jaouen200266, author = {Jaouen, L. and Atalla, N. and Brouard, B.}, title = {A method for the inverse characterization of poroelastic mechanical properties}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2002}, volume = {30}, number = {3}, pages = {66-67}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036751018&partnerID=40&md5=2e8d50885c908cb509ec94e86b540126} } |
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Kron, A., Doucet, P., Masson, P., Van Hoenacker, Y., Lapointe, J. and Micheau, P. | Unifying approaches to Mechanical Engineering design through a multidisciplinary effort | 2002 | ASEE Annual Conference Proceedings, pp. 6415-6427 | conference | URL |
Abstract: The completely renewed Mechanical Engineering curriculum features nine credits in mechatronics, including two formal courses (Mechatronics I and Mechatronics II) and a Project of Mechatronics course, as well as fifteen credits in system and product design, including a three credit Design Methodology course and a twelve credit Major Design Project extended over the last three terms of the program. These two large components of the program were developed according to the characteristics of each discipline. This paper presents the results up to the present of a multidisciplinary effort to unify the approaches to mechanical engineering design. It presents the enriched version of the Product Development Process (PDP) which has been developed in order to integrate the two approaches. In this respect, specific tools will be introduced in order to join the design process of a mechatronics system with the design of more traditional mechanical engineering products. This will be illustrated using a pill counter designed by the students as an example. In addition to the Mechatronics and the System and Product Design courses, the scope of this Educational Improvement Project extends to a Computer Programming course and a Project Management course. This paper shows the extent of the changes which are to be brought to all these courses. | |||||
BibTeX:
@conference{Kron20026415, author = {Kron, A. and Doucet, P. and Masson, P. and Van Hoenacker, Y. and Lapointe, J. and Micheau, P.}, title = {Unifying approaches to Mechanical Engineering design through a multidisciplinary effort}, journal = {ASEE Annual Conference Proceedings}, year = {2002}, pages = {6415-6427}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-8744304815&partnerID=40&md5=f916a4c06299cdc42b4b16edfe38d700} } |
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Langlois, C. and Atalla, N. | A fully hierarchical finite elements code for solving coupled elasto-poro-acoustic problems | 2002 | Canadian Acoustics - Acoustique Canadienne Vol. 30(3), pp. 76-77 |
article | URL |
Abstract: A fully hierarchical finite elements code for solving coupled elasto-poro-acoustic problems was presented. The performance of hierarchical elements was compared to linear elements for dynamic problems. The performance was demonstrated for a plate backed by a rigid cavity. The thickness of the plate was 3 mm and the thickness of the cavity was 0.35 m. Results showed that the order of approximation per unit length in the hierarchical code was 33 for the plate and 12.5 for the cavity. | |||||
BibTeX:
@article{Langlois200276, author = {Langlois, C. and Atalla, N.}, title = {A fully hierarchical finite elements code for solving coupled elasto-poro-acoustic problems}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2002}, volume = {30}, number = {3}, pages = {76-77}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036750263&partnerID=40&md5=aacfc65a072c0350aab2da7506a85267} } |
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Leboucher, E., Micheau, P., Berry, A. and L'espérance, A. | A stability analysis of a decentralized adaptive feedback active control system of sinusoidal sound in free space | 2002 | Journal of the Acoustical Society of America Vol. 111(1 I), pp. 189-199 |
article | DOI URL |
Abstract: In some cases, the implementation of active control of sound in free space requires a large number of secondary sources and error sensors. In terms of control hardware, this may translate into considerable processing power requirement. A practical method to decrease processing power is to decentralize the control; that is, implement many single-input, single-output independent controllers operating simultaneously instead of a large multiple-input, multiple-output system. The main drawback of decentralized control is the risk of global instability. The purpose of this paper is to derive conditions under which globally stable control system behavior can be obtained in the case of adaptive feedback decentralized control for a sinusoidal disturbance. The main objective is to give practical conditions derived from the small gain theorem and the Nyquist criterion for the stability of the control system. These conditions only take into account the geometrical arrangement of the secondary sources and error sensors. This analysis involves a new parameter ß called "performance index," which is associated with both the convergence of the individual controllers and the global stability of the system. Simulation and experimental results are shown to illustrate the effectiveness of the developed analytical tools. © 2002 Acoustical Society of America. | |||||
BibTeX:
@article{Leboucher2002189, author = {Leboucher, E. and Micheau, P. and Berry, A. and L'espérance, A.}, title = {A stability analysis of a decentralized adaptive feedback active control system of sinusoidal sound in free space}, journal = {Journal of the Acoustical Society of America}, year = {2002}, volume = {111}, number = {1 I}, pages = {189-199}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036146673&doi=10.1121%2f1.1427358&partnerID=40&md5=5a4d35b1dfbf37b647709fc95a4469d7}, doi = {https://doi.org/10.1121/1.1427358} } |
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Micheau, P., Mazouzi, M., Cyr, S. and Robert, R. | Learning control of a pump used in a liquid ventilator | 2002 | IFAC Proceedings Volumes (IFAC-PapersOnline) Vol. 15(1), pp. 151-155 |
conference | URL |
Abstract: The liquid ventilator have a peristaltic pump to deliver oxygenated PFC liquid to and from lungs of newborn. This paper is about the learning control of the pump. The problem is to track a reference signal of N ramps in spite of large measurement noise. The presented algorithm slowly learns the initial conditions of the controller for each desired ramp. Thus, little information are memorized to track repetitive sequence. The implementation is based on the use of as many PI controllers as ramps. An analysis of the control scheme and experimental results with the prototype of a total liquid ventilation system are presented. Copyright © 2002 IFAC. | |||||
BibTeX:
@conference{Micheau2002151, author = {Micheau, P. and Mazouzi, M. and Cyr, S. and Robert, R.}, title = {Learning control of a pump used in a liquid ventilator}, journal = {IFAC Proceedings Volumes (IFAC-PapersOnline)}, year = {2002}, volume = {15}, number = {1}, pages = {151-155}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945565241&partnerID=40&md5=b17f5fcb9aa9b5daaee8f94add17373c} } |
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Micheau, P., Buaka, P. and Bourassa, P. | Control of the simplest walking model with Lambda model | 2002 | IFAC Proceedings Volumes (IFAC-PapersOnline) Vol. 15(1), pp. 413-418 |
conference | URL |
Abstract: The analysis of the simplest biped walking machine can provide much insight into dynamics and control of human gait. The problem, in the sagittal plane, consists to control the impulse force under the swing foot and the torque between the legs in order to reach a stable limit cycle. The main contribution of this paper concerns the hierarchical control based on the physiological Lambda model and a pattern generator working with intermittent data. The feedback is tuned in order to obtain oscillations at the walking frequency. Simulation results present stable limit cycle. Copyright © 2002 IFAC. | |||||
BibTeX:
@conference{Micheau2002413, author = {Micheau, P. and Buaka, P. and Bourassa, P.}, title = {Control of the simplest walking model with Lambda model}, journal = {IFAC Proceedings Volumes (IFAC-PapersOnline)}, year = {2002}, volume = {15}, number = {1}, pages = {413-418}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945540449&partnerID=40&md5=1772f26ac8063a7b5089a20774493b0c} } |
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Pilon, D. and Panneton, R. | Free edge condition on porous materials | 2002 | Canadian Acoustics - Acoustique Canadienne Vol. 30(3), pp. 106-107 |
article | URL |
Abstract: The implementation of the free edge condition on an air-saturated open-cell porous layer was discussed. The different hypothesis and the finite element implementation of the free edge condition were also discussed. It was found that the measurements and the numerical results for the elastic foam were in good agreement with respect to each other. | |||||
BibTeX:
@article{Pilon2002106, author = {Pilon, D. and Panneton, R.}, title = {Free edge condition on porous materials}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2002}, volume = {30}, number = {3}, pages = {106-107}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036750447&partnerID=40&md5=6e02cc4b0e145aa0fb5135977ed60bcb} } |
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Amedin, C., Atalla, N. and Sgard, F. | The vibro-acoustics of a plate-backed cavity with non-homogeneous porous materials | 2001 | Canadian Acoustics - Acoustique Canadienne Vol. 29(3), pp. 28-29 |
article | URL |
Abstract: The effects of air pocket or elastic patches in a homogeneous porous domain were studied. The different domains were modeled by using accurate finite element methods. It was found that the addition of air pocket does not deteriorate the acoustic performance, but leads to a reduction of the weight of the configuration. On the other hand, an increase of the acoustic performance was obtained by insertion of elastic patches, but not without any increase of the configuration weight. | |||||
BibTeX:
@article{Amedin200128, author = {Amedin, C.K. and Atalla, N. and Sgard, F.}, title = {The vibro-acoustics of a plate-backed cavity with non-homogeneous porous materials}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2001}, volume = {29}, number = {3}, pages = {28-29}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035454403&partnerID=40&md5=e27d5e85b8c02decf0625e63b80df3f9} } |
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Atalla, N., Hamdi, M. and Panneton, R. | Enhanced weak integral formulation for the mixed (u,p) poroelastic equations | 2001 | Journal of the Acoustical Society of America Vol. 109(6), pp. 3065-3068 |
article | DOI URL |
Abstract: Recently Atalla et al. [J. Acoust. Soc. Am. 104, 1444-1452 (1998)] and Debergue et al. [J. Acoust. Soc. Am. 106, 2383-2390 (1999)] presented a weak integral formulation and the general boundary conditions for a mixed pressure-displacement version of the Biot's poroelasticity equations. Finite element discretization was applied to the formulation to solve 3D vibro-acoustic problems involving elastic, acoustic, and poroelastic domains. In this letter, an enhancement of the weak integral formulation is proposed to facilitate its finite element implementation. It is shown that this formulation simplifies the assembly process of the poroelastic medium, the imposition of its boundary conditions, and its coupling with elastic and acoustic media. © 2001 Acoustical Society of America. | |||||
BibTeX:
@article{Atalla20013065, author = {Atalla, N. and Hamdi, M.A. and Panneton, R.}, title = {Enhanced weak integral formulation for the mixed (u,p) poroelastic equations}, journal = {Journal of the Acoustical Society of America}, year = {2001}, volume = {109}, number = {6}, pages = {3065-3068}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034965677&doi=10.1121%2f1.1365423&partnerID=40&md5=dbcb8989f4a90a241c0e6cebbcc483b6}, doi = {https://doi.org/10.1121/1.1365423} } |
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Atalla, N., Panneton, R., Sgard, F. and Olny, X. | Acoustic absorption of macro-perforated porous materials | 2001 | Journal of Sound and Vibration Vol. 243(4), pp. 659-678 |
article | DOI URL |
Abstract: The paper discusses the absorption of non-homogeneous thin macro-porous materials. In particular, the acoustic absorption performance of three-dimensional (3-D) porous media made up from thin porous patches, with different acoustic properties, is investigated using a numerical model. The presented model considers the configuration wherein the material is bonded onto the hard-walled termination of a semi-infinite rectangular waveguide. It couples a finite element description for the porous material to a modal description in the waveguide and uses a power balance approach to accurately quantify the absorption performance of the material. Experimental results are presented to validate the model in the special case of a macro-perforated porous material. Using this model a parameter study is presented. It is shown that absorption may be increased at low frequency by using non-homogeneous patch-works. © 2001 Academic Press. | |||||
BibTeX:
@article{Atalla2001659, author = {Atalla, N. and Panneton, R. and Sgard, F.C. and Olny, X.}, title = {Acoustic absorption of macro-perforated porous materials}, journal = {Journal of Sound and Vibration}, year = {2001}, volume = {243}, number = {4}, pages = {659-678}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035859195&doi=10.1006%2fjsvi.2000.3435&partnerID=40&md5=16c65aa720a9d738ab3ab3112c4b1448}, doi = {https://doi.org/10.1006/jsvi.2000.3435} } |
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Berry, A., Foin, O. and Szabo, J. | Three-dimensional elasticity model for a decoupling coating on a rectangular plate immersed in a heavy fluid | 2001 | Journal of the Acoustical Society of America Vol. 109(6), pp. 2704-2714 |
article | DOI URL |
Abstract: This paper presents an analysis of the vibroacoustic response of a finite, simply supported rectangular plate covered by a layer of decoupling material and immersed in a heavy fluid. An exact formulation using the three-dimensional theory of elasticity for the decoupling material is derived for this problem, thereby extending previous studies that were limited to infinite plates. The paper details the constitutive equations of the problem and the analytical method of solution. Numerical results show that shear waves in the decoupling material generally have little influence on the sound radiation in the heavy fluid. Comparisons with a locally reacting model of the decoupling material and with the simple model of House [Proc. I.O.A. 13(3), 166-173 (1991)] are also presented. © 2001 Acoustical Society of America. | |||||
BibTeX:
@article{Berry20012704, author = {Berry, A. and Foin, O. and Szabo, J.P.}, title = {Three-dimensional elasticity model for a decoupling coating on a rectangular plate immersed in a heavy fluid}, journal = {Journal of the Acoustical Society of America}, year = {2001}, volume = {109}, number = {6}, pages = {2704-2714}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034965539&doi=10.1121%2f1.1372224&partnerID=40&md5=6f74874eaf02d229a1527f853e46c9bc}, doi = {https://doi.org/10.1121/1.1372224} } |
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Berry, A. | Advanced sensing strategies for the active control of vibration and structural radiation | 2001 | Noise Control Engineering Journal Vol. 49(1), pp. 54-65 |
article | DOI URL |
Abstract: The active control of sound and vibration of extended systems and structures requires a thorough understanding of the physical mechanisms involved in the generation and propagation of the disturbance. For the active control system to be physically compact and efficient in globally reducing the disturbance, the secondary sources and error sensors usually need to be located close to the primary source (possibly integrated on the structure in the case of active structural acoustic control). On the other hand, minimizing the acoustic near-field or structural response does not guarantee that the far-field, propagating disturbance is minimized accordingly. This then poses the problem of the active control strategy, definition of the cost function and type of error sensors to be used in the control system. In this review paper, advanced sensing strategies that address this generic problem are presented in the case of several vibration/acoustic systems, and associated advantages and limitations are discussed. These include structural intensity sensing in the active control of beam vibration, near-field acoustic intensity sensing in the active control of free space radiation from extended sources, and structural volume velocity and discrete strain sensing in the active structural acoustic control. | |||||
BibTeX:
@article{Berry200154, author = {Berry, A.}, title = {Advanced sensing strategies for the active control of vibration and structural radiation}, journal = {Noise Control Engineering Journal}, year = {2001}, volume = {49}, number = {1}, pages = {54-65}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034981938&doi=10.3397%2f1.2839640&partnerID=40&md5=68f7b9c38823fa3fa6f524b80cad7644}, doi = {https://doi.org/10.3397/1.2839640} } |
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Champoux, Y., Paillard, B. and Machéto, D. | Moment excitation using two synchronized impact hammers | 2001 | Proceedings of the International Modal Analysis Conference - IMAC Vol. 1, pp. 543-549 |
article | URL |
Abstract: Moment mobilities are difficult to measure because there is no simple way to excite a structure with a well controlled moment. In this paper, a technique to apply a pure moment is presented. It is based on a simple approach which uses two impact forces applied respectively by two impact hammers. This paper will focus on the detailed description of the experimental system developed to obtain identical synchronized forces. Two hammers driven by electric motors controlled by a Digital Signal Processor are used. Experimental results are compared to theoretical predictions. It is shown that the technique yields to accurate measurements of moment frequency response functions (FRF). | |||||
BibTeX:
@article{Champoux2001543, author = {Champoux, Y. and Paillard, B. and Machéto, D.}, title = {Moment excitation using two synchronized impact hammers}, journal = {Proceedings of the International Modal Analysis Conference - IMAC}, year = {2001}, volume = {1}, pages = {543-549}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035054070&partnerID=40&md5=f9307ae9aeb14e8ad07dc63d8478aa85} } |
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Dauchez, N., Sahraoui, S. and Atalla, N. | Convergence of poroelastic finite elements based on Biot displacement formulation | 2001 | Journal of the Acoustical Society of America Vol. 109(1), pp. 33-40 |
article | DOI URL |
Abstract: The convergence of linear poroelastic elements based on Biot displacement formulation is investigated. The aim is to determine a mesh criterion that provides reliable results under a given frequency limit. The first part deals with 1D applications for which resonance frequencies can be related to Biot wavelengths. Their relative contributions to the motion are given in order to determine if the mesh criteria for monophasic media are suitable for poroelastic media. The imposition of six linear elements per wavelength is found for each Biot wave as a primary condition for convergence. For 3D applications, convergence rules are derived from a generic configuration, i.e., a clamped porous layer. Because of the complex deformation, the previous criterion is shown to be insufficient. Influence of the coupling between the two phases is demonstrated. © 2001 Acoustical Society of America. | |||||
BibTeX:
@article{Dauchez200133, author = {Dauchez, N. and Sahraoui, S. and Atalla, N.}, title = {Convergence of poroelastic finite elements based on Biot displacement formulation}, journal = {Journal of the Acoustical Society of America}, year = {2001}, volume = {109}, number = {1}, pages = {33-40}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035169747&doi=10.1121%2f1.1289924&partnerID=40&md5=e11b580099afd6660a0bc24963329845}, doi = {https://doi.org/10.1121/1.1289924} } |
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Ghinet, S. and Atalla, N. | Sound transmission loss of insulating complex structures | 2001 | Canadian Acoustics - Acoustique Canadienne Vol. 29(3), pp. 26-27 |
article | URL |
Abstract: The Transfer Matrix Method (TMM) is extended to handle the transmission loss of finite stiffened and orthotropic structures lined by porous materials in a multi-layered configuration. The effects of curvature, stiffeners and heterogeneity are considered. The resulting model is easily adaptable to multi-layer configurations. | |||||
BibTeX:
@article{Ghinet200126, author = {Ghinet, S. and Atalla, N.}, title = {Sound transmission loss of insulating complex structures}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2001}, volume = {29}, number = {3}, pages = {26-27}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035454543&partnerID=40&md5=d924eb8a9b7fadb0af2f0587fd545a07} } |
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Guertin, L., Berry, A. and Charron, F. | A finite element formulation for laminated elastic - Piezoelectric plates using a discrete layer | 2001 | Transactions of the Canadian Society for Mechanical Engineering Vol. 25(3-4), pp. 315-333 |
article | URL |
Abstract: The dynamics of multilayer elastic structures with embedded or surface piezoelectric layers is investigated in this article. The dynamics of such systems in various configurations (sensing or actuating layers) involves the solution of coupled electro-mechanical equations that describe the elastic variable in the laminate and the electric variables in the piezoelectric layers. This article is concerned with an efficient and accurate modeling of thin elastic-piezoelectric plane laminates using a discrete-layer approach. In contrast to other approaches that require a discretization of the laminate through its thickness, the proposed approach assumes linear variations of elastic displacements and electric potentials through each layer of the laminate, and uses displacement and shear stress continuity requirements at the interface between layers in order to condense the elastic degrees of freedom of the problem. The independent variables of the laminate are the elastic variables of a reference layer and the electric potentials of each piezoelectric layer. Formulations and numerical results are presented for the free vibrations of elastic-piezoelectric laminates in various configurations (closed or open electrodes), and for the actuation by a piezoelectric layer, or in the response of a sensory piezoelectric layer. | |||||
BibTeX:
@article{Guertin2001315, author = {Guertin, L. and Berry, A. and Charron, F.}, title = {A finite element formulation for laminated elastic - Piezoelectric plates using a discrete layer}, journal = {Transactions of the Canadian Society for Mechanical Engineering}, year = {2001}, volume = {25}, number = {3-4}, pages = {315-333}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035727351&partnerID=40&md5=4da9da5fab1e9e6063265313f2a5a0de} } |
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Hamdi, M., Mebarek, L., Omrani, A., Atalla, N., Fortez, M., Crignon, G. and Lullier, S. | An efficient finite element formulation for the analysis of acoustic and elastic waves propagation in sound packages | 2001 | SAE Technical Papers | article | DOI URL |
Abstract: A new mixed finite element formulation very well adapted to analyze the propagation of elastic and acoustic waves in porous absorbing media is presented. The proposed new formulation is based on modified Biot's equations [1,2,3] written in terms of the skeleton displacement and the acoustic pressure in the interstitial fluid. It generalizes the previous formulation proposed in reference [11], and has the great advantage over existing formulations [5, 6, 7, 8, 9, 10, 11, 12 and 13] of automatically satisfying interior and exterior boundary conditions without having to compute surface coupling integrals at porous sub-domain interfaces. When elastic forces in the skeleton are neglected, the formulation automatically degenerates to an equivalent fluid model taking into account inertial coupling with the skeleton. In addition it reduces to a minimum the number of degrees of freedom (dofs) and considerably simplify the modeling effort by allowing the computation of the generalized impedance matrix added by complex porous components to the vibro-acoustic impedance matrix of the bare vehicle body. Thus it simplifies the cooperative work between vehicle suppliers and manufacturers. This generalized mixed formulation and associated equivalent fluid model has been implemented by STRACO (France) in RAYON-PEM Solver. It is shown in this paper, that the numerical results predicted with RAYON-PEM agrees very well with experimental results using bazooka impedance tube and RTC tests. Copyright © 2001 Society of Automotive Engineers, Inc. | |||||
BibTeX:
@article{Hamdi2001, author = {Hamdi, M.A. and Mebarek, L. and Omrani, A. and Atalla, N. and Fortez, M. and Crignon, G. and Lullier, S.}, title = {An efficient finite element formulation for the analysis of acoustic and elastic waves propagation in sound packages}, journal = {SAE Technical Papers}, year = {2001}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877560599&doi=10.4271%2f2001-01-1406&partnerID=40&md5=f8abadb14b6a86f3ce333ca78c14e3e6}, doi = {https://doi.org/10.4271/2001-01-1406} } |
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Langlois, C., Panneton, R. and Atalla, N. | Polynomial relations for quasi-static mechanical characterization of isotropic poroelastic materials | 2001 | Journal of the Acoustical Society of America Vol. 110(6), pp. 3032-3040 |
article | DOI URL |
Abstract: This paper proposes a quasi-static method for the characterization of the elastic properties of poroelastic materials. The method is based on the development of polynomial relations among compression stiffness, Young's modulus, Poisson's ratio, and shape factor derived from high order axisymmetrical finite element simulations on a disk-shaped poroelastic sample under static compression. The shape factor is defined as half the radius to thickness ratio of the sample. The polynomial relations account for the fact that the disk sample "wants" to bulge sideways when compressed between two rigid plates on which it is bonded. A compression test setup is used to measure the compression stiffness of two disk samples of different large shape factors. The measured stiffnesses together with the polynomial relations lead to a system of two equations and two unknowns. The solution of the system yields the Young's modulus and Poisson's ratio of the poroelastic material. Employing the proposed quasi-static method, Young's modulus, Poisson's ratio, and loss factor are measured for a poroelastic foam. The measured elastic properties are used in the Biot poroelasticity theory to predict the sound absorption coefficient of the foam. The prediction is finally compared with a standing wave tube measurement. A good correlation is obtained. © 2001 Acoustical Society of America. | |||||
BibTeX:
@article{Langlois20013032, author = {Langlois, C. and Panneton, R. and Atalla, N.}, title = {Polynomial relations for quasi-static mechanical characterization of isotropic poroelastic materials}, journal = {Journal of the Acoustical Society of America}, year = {2001}, volume = {110}, number = {6}, pages = {3032-3040}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035205794&doi=10.1121%2f1.1419091&partnerID=40&md5=5b903c08f20bb18bda5eafeaefabe299}, doi = {https://doi.org/10.1121/1.1419091} } |
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Masson, P., Audrain, P., Berry, A., Pascal, J.-C. and Gazengel, B. | A novel implementation of active structural flow control | 2001 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 4327(1), pp. 560-569 |
article | DOI URL |
Abstract: Active structural flow control has emerged as an effective way to suppress the vibration of large structures by controlling in the vicinity of the disturbances with a limited number of sensors and actuators. This is in contrast with other active structural control strategies which employ distributed sensors and actuators to provide a global control of the modes of the structure. This paper presents theoretical and experimental structural intensity control results, where the instantaneous intensity is completely taken into account in the control algorithm, i.e. all the terms are considered in the real-time control process and, in particular, the evanescent waves are considered in this approach. Moreover, both the flexural and extensional waves are taken into account in the control algorithm. As they are especially well-suited for integration into structures in order to create smart materials, piezoelectric strain sensors (PVDF) are used in the sensing approach. The structural intensity is estimated from the discrete strain measurements using a finite difference scheme. A feedforward filtered-X LMS algorithm is adapted to this energy-based control problem, involving a non-positive definite quadratic form in general. In this respect, the approach is limited to cases where the geometry is such that the intensity component will have the same sign for the control source and the primary disturbance. Experimental validation of the approach is conducted on a structure made of a beam connected to a plate, where the beam is covered with viscoelastic material. A comparison of the proposed approach is made with classical acceleration control and these results show that intensity control using strain sensors allows the error sensors to be placed closer to the control source and the primary disturbance, while preserving a good control performance. © 2001 SPIE. | |||||
BibTeX:
@article{Masson2001560, author = {Masson, P. and Audrain, P. and Berry, A. and Pascal, J.-C. and Gazengel, B.}, title = {A novel implementation of active structural flow control}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2001}, volume = {4327}, number = {1}, pages = {560-569}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034768257&doi=10.1117%2f12.436565&partnerID=40&md5=8c462b47433015dcee05882aed79ba45}, doi = {https://doi.org/10.1117/12.436565} } |
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Mencik, J.-M., Champoux, Y. and Berry, A. | Development of a blocked pressure criterion for application of the principle of acoustic reciprocity | 2001 | Journal of Sound and Vibration Vol. 245(4), pp. 669-684 |
article | DOI URL |
Abstract: The principle of acoustic reciprocity can be applied in practice to estimate the sound radiation of a vibrating surface, from an inverse measurement of the Green function. This principle is especially useful in evaluating and ranking the sound radiation from individual vibrating components of a complex mechanical system. Usually, a blocked pressure assumption is needed in order to simplify the formulation of the reciprocity technique. This paper examines the validity of the blocked pressure hypothesis in the context of the reciprocity method, and suggests a "blocked pressure criterion" to rigorously quantify the impact of this hypothesis on the sound radiation prediction. This criterion is tested numerically on a system consisting of two coplanar, simply supported thin baffled plates that are mechanically uncoupled. It is shown that the numerical results support the conclusions obtained from the blocked pressure criterion. © 2001 Academic Press. | |||||
BibTeX:
@article{Mencik2001669, author = {Mencik, J.-M. and Champoux, Y. and Berry, A.}, title = {Development of a blocked pressure criterion for application of the principle of acoustic reciprocity}, journal = {Journal of Sound and Vibration}, year = {2001}, volume = {245}, number = {4}, pages = {669-684}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035939965&doi=10.1006%2fjsvi.2000.3606&partnerID=40&md5=fddfaebe2b2f1883b0a8d4d51a6f6cac}, doi = {https://doi.org/10.1006/jsvi.2000.3606} } |
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Micheau, P., Kron, A. and Bourassa, P. | Analysis of human postural stability based on the inverted pendulum model with time-delay in feedback | 2001 | Proceedings of the American Control Conference Vol. 3, pp. 2297-2298 |
conference | URL |
Abstract: For normal quiet standing the ankle strategy is used for human posture. The musculoskeletic system can be viewed as an inverted pendulum stabilised by a feedback loop with the lambda control. Mathematical modelling of the musculo-skeletal system under lambda control is presented as a nonlinear system with time-delay in feedback. Necessary conditions of asymptotic stability and a practical analytic expression of the delay margin are presented. To authenticate the model, five subjects are experimented. | |||||
BibTeX:
@conference{Micheau20012297, author = {Micheau, P. and Kron, A. and Bourassa, P.}, title = {Analysis of human postural stability based on the inverted pendulum model with time-delay in feedback}, journal = {Proceedings of the American Control Conference}, year = {2001}, volume = {3}, pages = {2297-2298}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034848226&partnerID=40&md5=061f4dbfa89eea69f4628fb1bf05a256} } |
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Tournour, M., Atalla, N., Chiello, O. and Sgard, F. | Validation, performance, convergence and application of free interface component mode synthesis | 2001 | Computers and Structures Vol. 79(20-21), pp. 1861-1876 |
article | DOI URL |
Abstract: During the past three decades the component mode synthesis methods were extensively presented in the literature. Unfortunately, it seems that no convergence criterion was clearly defined in the literature. A free interface method is presented in this paper and six test cases are used to evaluate the number of retained substructure modes necessary to ensure convergence. The approach is validated numerically and experimentally. Also, an application of the proposed free interface method to optimization design is presented. © 2001 Elsevier Science Ltd. All rights reserved. | |||||
BibTeX:
@article{Tournour20011861, author = {Tournour, M.A. and Atalla, N. and Chiello, O. and Sgard, F.}, title = {Validation, performance, convergence and application of free interface component mode synthesis}, journal = {Computers and Structures}, year = {2001}, volume = {79}, number = {20-21}, pages = {1861-1876}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035415696&doi=10.1016%2fS0045-7949%2801%2900114-6&partnerID=40&md5=85713cf36c251c365b80794b25b2798f}, doi = {https://doi.org/10.1016/S0045-7949(01)00114-6} } |
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Wojtowicki, J.-L., Champoux, Y. and Thibault, J. | Modal properties of road bikes vs ride comfort | 2001 | Proceedings of the International Modal Analysis Conference - IMAC Vol. 1, pp. 648-652 |
article | URL |
Abstract: Road bikes evolve constantly due to the fact that a large number of new high-tech materials are used. For road bikes, comfort is an important issue but there is little information on metrics that would quantify the level of comfort. In this paper, modal analysis is used to analyze the dynamic behavior of a road bike. The influence of the rider on modal parameters is examined. The link between vibration level on the handle bar in riding conditions and modal behavior of the bike is also examined. Three technologically different bikes are used on a test track to analyze the influence of design and components on the vibration level perceived by the rider. | |||||
BibTeX:
@article{Wojtowicki2001648, author = {Wojtowicki, J.-L. and Champoux, Y. and Thibault, J.}, title = {Modal properties of road bikes vs ride comfort}, journal = {Proceedings of the International Modal Analysis Conference - IMAC}, year = {2001}, volume = {1}, pages = {648-652}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035051513&partnerID=40&md5=127abb15a524472fa252bd3ce0c9f840} } |
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Amédin, C., Atalla, N. and Sgard, F. | Acoustic absorption of non-homogeneous poro-elastic materials | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 90-91 |
article | URL |
Abstract: A model to evaluate the acoustic absorption performance of configurations consisting of a porous material, bonded onto the hard termination of a semi-infinite rectangular waveguide is presented. A power balance approach is used to evaluate the performance of the porus material using the absorption coefficient. An experimental validation is performed for a macro-perforated material, which consists in a mineral wool with periodic holes containing air. The absorption coefficient of non-homogeneous porous-elastic layers is predicted. | |||||
BibTeX:
@article{Amédin200090, author = {Amédin, C.K. and Atalla, N. and Sgard, F.}, title = {Acoustic absorption of non-homogeneous poro-elastic materials}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {90-91}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0342521316&partnerID=40&md5=83508504a1ab12b42dbf1036ee528fed} } |
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Atalla, Y. and Panneton, R. | Inverse characterization of the geometrical macroscopic parameters of porous materials | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 80-81 |
article | URL |
Abstract: The inverse problem of acoustically determining the geometrical macroscopic parameters of an open celled porous specimen is analyzed. The inverse characterization scheme is based on the equivalent fluid model, in which the solid frame is assumed to be rigid. The numerical predictions using the inversely identified parameters are compared to the measured sound absorption coefficient of the specimen for different thicknesses. | |||||
BibTeX:
@article{Atalla200080, author = {Atalla, Y. and Panneton, R.}, title = {Inverse characterization of the geometrical macroscopic parameters of porous materials}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {80-81}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034268584&partnerID=40&md5=5235d4f520ea62c922fd02f2831db674} } |
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Audrain, P., Masson, P. and Berry, A. | Investigation of active structural intensity control in finite beams: Theory and experiment | 2000 | Journal of the Acoustical Society of America Vol. 108(2), pp. 612-623 |
article | DOI URL |
Abstract: An investigation of structural intensity control is presented in this paper. As opposed to previous work, the instantaneous intensity is completely taken into account in the control algorithm, i.e., all the terms are considered in the real-time control process and, in particular, the evanescent waves are considered in this approach. A finite difference approach using five accelerometers is used as the sensing scheme. A feedforward filtered-X least mean square algorithm is adapted to this energy-based control problem, involving a nonpositive definite quadratic form in general. In this respect, the approach is limited to cases where the geometry is such that the intensity component will have the same sign for the control source and the primary disturbance. Results from numerical simulations are first presented to illustrate the benefit of using a cost function based on structural intensity. Experimental validation of the approach is conducted on a free-free beam covered with viscoelastic material. A comparison is made between classical acceleration control and structural intensity control and the performance of both approaches is presented. These results confirm that using intensity control allows the error sensors to be placed closer to the control source and the primary disturbance, while preserving a good control performance. (C) 2000 Acoustical Society of America. | |||||
BibTeX:
@article{Audrain2000612, author = {Audrain, P. and Masson, P. and Berry, A.}, title = {Investigation of active structural intensity control in finite beams: Theory and experiment}, journal = {Journal of the Acoustical Society of America}, year = {2000}, volume = {108}, number = {2}, pages = {612-623}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033886089&doi=10.1121%2f1.429593&partnerID=40&md5=f675153b51177bd42c804f6e8a82bf3c}, doi = {https://doi.org/10.1121/1.429593} } |
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Audrain, P., Masson, P. and Berry, A. | Comparison of wave sensing stragegies for active structural acoustic control [BibTeX] |
2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 62-63 |
article | URL |
BibTeX:
@article{Audrain200062, author = {Audrain, P. and Masson, P. and Berry, A.}, title = {Comparison of wave sensing stragegies for active structural acoustic control}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {62-63}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034269222&partnerID=40&md5=3a1c1a5092517535d08e19a368cf2863} } |
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Barrette, M., Berry, A. and Beslin, O. | Vibration of stiffened plates using hierarchical trigonometric functions | 2000 | Journal of Sound and Vibration Vol. 235(5), pp. 727-747 |
article | DOI URL |
Abstract: The vibration analysis of stiffened plates using hierarchical finite elements with a set of local trigonometric interpolation functions is presented. The local functions extend on the plate domain comprised between consecutive stiffeners, thereby allowing a coarse discretization of the global structure. Convergence studies as well as comparison of the present approach with the literature and experimental results are presented. The great numerical stability of the trigonometric functions and their readiness for symbolic manipulations make them potentially attractive for vibration and sound radiation analysis in the mid-frequency range. | |||||
BibTeX:
@article{Barrette2000727, author = {Barrette, M. and Berry, A. and Beslin, O.}, title = {Vibration of stiffened plates using hierarchical trigonometric functions}, journal = {Journal of Sound and Vibration}, year = {2000}, volume = {235}, number = {5}, pages = {727-747}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034245406&doi=10.1006%2fjsvi.2000.2978&partnerID=40&md5=d18a01a1838df6c85dc4518f847a862f}, doi = {https://doi.org/10.1006/jsvi.2000.2978} } |
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Beslin, O., Foin, O. and Nicolas, J. | Hybrid tool for quickly estimating the radiated acoustic power from a vibrating structure in a multiple-source environment | 2000 | Journal of the Acoustical Society of America Vol. 107(2), pp. 840-850 |
article | DOI URL |
Abstract: This paper presents a new hybrid method for predicting overestimating and underestimating indicators of the acoustic power radiated by a vibrating surface even in the presence of other surrounding acoustic sources. This method is applicable to plates or low curvature surfaces radiating in open acoustic fields. The method is hybrid in the sense that the vibration field is measured and the parietal pressure field is predicted considering two extreme academic cases 'baffled' and 'unbaffled.' Many simplifications are made and justified in order to save running time. The method is successfully validated in comparison with experimental results on both laboratory and real life structures. This method has led to a quick tool, allowing one to obtain a good approximation of the radiated power in a few minutes. It provides a natural extension of a classical analyzer for vibroacoustics engineering. (C) 2000 Acoustical Society of America. | |||||
BibTeX:
@article{Beslin2000840, author = {Beslin, O. and Foin, O. and Nicolas, J.}, title = {Hybrid tool for quickly estimating the radiated acoustic power from a vibrating structure in a multiple-source environment}, journal = {Journal of the Acoustical Society of America}, year = {2000}, volume = {107}, number = {2}, pages = {840-850}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033952866&doi=10.1121%2f1.428267&partnerID=40&md5=17baed6919ffb68a2fef534e1ea0e44d}, doi = {https://doi.org/10.1121/1.428267} } |
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Bissonnette, C. and Champoux, Y. | Predicting the movement of an engine supported by an elastic suspension during a transient phenomenon | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 144-145 |
article | URL |
Abstract: An experimental approach is presented to predict the movement of an engine supported by an elastic suspension during a transient phenomenon. An experimental approach to determine the nonlinear dynamic properties of a suspension is developed. An equation of motion is elaborated using the experimental properties of the suspension. | |||||
BibTeX:
@article{Bissonnette2000144, author = {Bissonnette, C. and Champoux, Y.}, title = {Predicting the movement of an engine supported by an elastic suspension during a transient phenomenon}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {144-145}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034264772&partnerID=40&md5=c6fda018061ba718806cef144a3811f6} } |
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Blanchet, D. and Champoux, Y. | Comparison of objective functions for engine mounts optimization | 2000 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 4062, pp. I/- |
conference | URL |
Abstract: Engine's vibration propagating through its suspension is often responsible for low frequency noise perceived by vehicle occupants. In the design process and at early stage of development, it is useful to have an efficient way of estimating the properties of an engine suspension since these properties directly dictate the engine's structureborne vibration contribution to total noise of a vehicle. These properties include stiffness, position, orientation and number of engine mounts. A good design will provide adequate support of the engine as well as low power transmitted to the structure in order to reduce as much as possible the transmitted structureborne vibration and the radiated acoustic energy. The purpose of this paper is to present an efficient and straightforward approach to develop and optimize engine suspension. Various objective functions such as transmitted forces, power flow injected in the elastic base structure, vibration levels taken at critical locations and driver ears acoustic pressure levels can be used. Using MatlabTM, a dedicated and user-friendly software has been developed to assist and guide suspension designers. It allows the user to model each of the different parts of the system either as rigid bodies or as flexible structures. | |||||
BibTeX:
@conference{Blanchet2000, author = {Blanchet, Denis and Champoux, Yvan}, title = {Comparison of objective functions for engine mounts optimization}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2000}, volume = {4062}, pages = {I/-}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033875718&partnerID=40&md5=9b5f262aaf8b06cc841c205456dfdae8} } |
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Blanchet, D. and Champoux, Y. | Comparison of objective functions for engine mounts optimization | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 140-141 |
article | URL |
Abstract: A straightforward method is presented to model the behavior of an elastically supported engine attached to a rigid or a flexible structure. The proposed suspension optimization approach seeks to minimize passenger's perception of noise and vibration inside vehicles. It allows designers to model structure borne noise generated by the engine. | |||||
BibTeX:
@article{Blanchet2000140, author = {Blanchet, D. and Champoux, Y.}, title = {Comparison of objective functions for engine mounts optimization}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {140-141}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034269224&partnerID=40&md5=399b6ee610d7259101b5570559e852c8} } |
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Blanchet, D. and Champoux, Y. | Comparison of objective functions for engine mounts optimization | 2000 | Proceedings of the International Modal Analysis Conference - IMAC Vol. 1, pp. 631-636 |
article | URL |
Abstract: Engine's vibration propagating through its suspension is often responsible for low frequency noise perceived by vehicle occupants. In the design process and at early stage of development, it is useful to have an efficient way of estimating the properties of an engine suspension since these properties directly dictate the engine's structureborne vibration contribution to total noise of a vehicle. These properties include stiffness, position, orientation and number of engine mounts. A good design will provide adequate support of the engine as well as low power transmitted to the structure in order to reduce as much as possible the transmitted structureborne vibration and the radiated acoustic energy. The purpose of this paper is to present an efficient and straightforward approach to develop and optimize engine suspension. Various objective functions such as transmitted forces, power flow injected in the elastic base structure, vibration levels taken at critical locations and driver ears acoustic pressure levels can be used. Using MatlabTM, a dedicated and user-friendly software has been developed to assist and guide suspension designers. It allows the user to model each of the different parts of the system either as rigid bodies or as flexible structures. | |||||
BibTeX:
@article{Blanchet2000631, author = {Blanchet, Denis and Champoux, Yvan}, title = {Comparison of objective functions for engine mounts optimization}, journal = {Proceedings of the International Modal Analysis Conference - IMAC}, year = {2000}, volume = {1}, pages = {631-636}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033905341&partnerID=40&md5=05f0054ddc0499205ef44eb75da9a66e} } |
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Bolduc, M., Panneton, R., Atalla, N. and Wojtowicki, J.-L. | Numerical and experimental characterization of the transmission loss of complex composite panels | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 104-105 |
article | URL |
Abstract: A numerical method was used to predict the sound transmission loss of simple and complex composite panels. The configurations which were used are a simple plate, an air-filled double plate, and a double plate with cavity absorption. Both the finite element method and boundary element method are used for numerical calculations. The experimental setup is a coupled anechoic-reverberant room. Two sources are used to generate the diffuse sound field. | |||||
BibTeX:
@article{Bolduc2000104, author = {Bolduc, M. and Panneton, R. and Atalla, N. and Wojtowicki, J.-L.}, title = {Numerical and experimental characterization of the transmission loss of complex composite panels}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {104-105}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034268617&partnerID=40&md5=af7cf2925b363f09e448bba0dc65a9d9} } |
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Champoux, Y., Beslin, O., Gautier, B., Macheto, D. and Paillard, B. | Moment mobility measurement using an impact force couple | 2000 | Proceedings of the 25th International Conference on Noise and Vibration Engineering, ISMA, pp. 1011-1018 | conference | URL |
Abstract: Moment mobilities are difficult to measure because there is no simple way to excite a structure with a well controlled moment. In this paper, a technique to apply a pure moment is presented. It is based on a simple approach which uses two impact forces applied respectively by two impact hammers. The limits and the validity of this approach is first examined theoretically on a simply supported plate. The coupling between the two hammers and the structure during the impact phase is considered. Using two impact hammers driven by electric motors controlled by a Digital Signal Processor, experimental results are compared to theoretical predictions. It is shown that the technique yields accurate measurements of moment frequency response functions. | |||||
BibTeX:
@conference{Champoux20001011, author = {Champoux, Y. and Beslin, O. and Gautier, B. and Macheto, D. and Paillard, B.}, title = {Moment mobility measurement using an impact force couple}, journal = {Proceedings of the 25th International Conference on Noise and Vibration Engineering, ISMA}, year = {2000}, pages = {1011-1018}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-13444300995&partnerID=40&md5=0d0b500b6c1e4ecb7aeb7bce401187cd} } |
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Dauchez, N., Sahraoui, S. and Atalla, N. | Validation of 3-D poroelastic finite element from the impedance measurement of a vibrating foam sample | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 94-95 |
article | URL |
Abstract: The real 3-D motion of porous materials was validated by comparing it with skeleton motion and acoustic coupling. The impedance of a resonant porous sample in a duct with lateral air gap was measured. A quasistatic measurement method was used to investigate both isotropic and axisymmetrical viscoelastic skeletons. For the experiment, the porous sample and the boundary conditions are so chosen that one resonance of the skeleton can be observed in the frequency range of 50 Hz to 500 Hz. The use of isotropic law is efficient when mechanical parameters are related to the kind of deformation of the material. | |||||
BibTeX:
@article{Dauchez200094, author = {Dauchez, N. and Sahraoui, S. and Atalla, N.}, title = {Validation of 3-D poroelastic finite element from the impedance measurement of a vibrating foam sample}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {94-95}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034264899&partnerID=40&md5=7bad470057a75fb0aa44b59b4cdafb0f} } |
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Foin, O., Berry, A. and Szabo, J. | Acoustic radiation from an elastic baffled rectangular plate covered by a decoupling coating and immersed in a heavy acoustic fluid | 2000 | Journal of the Acoustical Society of America Vol. 107(5 I), pp. 2501-2510 |
article | DOI URL |
Abstract: The vibroacoustic behavior of an elastic, simply supported rectangular plate covered by a locally reacting decoupling layer supporting thickness deformation is presented. The model simulates the vibration and acoustic response of the system immersed in water and subjected to a point force disturbance. A simplified version of the theory is derived in the limiting case of a large decoupling (low mechanical impedance of the layer/high frequency). An appropriate vibratory indicator, representative of the acoustic attenuation provided by the decoupling treatment, and independent of the structure dimensions, is also investigated from the perspective of small- scale laboratory characterization (C) 2000 Acoustical Society of America. | |||||
BibTeX:
@article{Foin20002501, author = {Foin, O. and Berry, A. and Szabo, J.}, title = {Acoustic radiation from an elastic baffled rectangular plate covered by a decoupling coating and immersed in a heavy acoustic fluid}, journal = {Journal of the Acoustical Society of America}, year = {2000}, volume = {107}, number = {5 I}, pages = {2501-2510}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034025870&doi=10.1121%2f1.428638&partnerID=40&md5=d6e7f1b109d690b1e64407eb78b6f985}, doi = {https://doi.org/10.1121/1.428638} } |
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Ghinet, S. and Atalla, N. | Transmission loss optimization of multi-layer noise control treatments | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 96-97 |
article | URL |
Abstract: The optimization of the diffuse field transmission loss through double-wall sound barriers is discussed. The sound barriers are made from a porous decoupling material sandwiched between an elastic skin and a septum. The study aims at optimizing the frequency band averaged diffuse field transmission loss of the three layer system. The optimization problem is implemented by combining the optimization engine to an acoustic-indicator engine for the transmission loss calculation. The aim is to tailor certain material properties of the porous layer to achieve the minimum noise condition. | |||||
BibTeX:
@article{Ghinet200096, author = {Ghinet, S. and Atalla, N.}, title = {Transmission loss optimization of multi-layer noise control treatments}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {96-97}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034264901&partnerID=40&md5=84b1809e259826740661c4faaeff6ffa} } |
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Hamdi, M., Mebarek, L., Omrani, A. and Atalla, N. | An efficient formulation for the analysis of acoustic and elastic waves propagation in porous -elastic materials | 2000 | Proceedings of the 25th International Conference on Noise and Vibration Engineering, ISMA, pp. 1465-1470 | conference | URL |
Abstract: A new mixed finite element formulation very well adapted to analyze the propagation of elastic and acoustic waves in porous absorbing media is presented. The proposed new formulation is based on modified Biot's equations written in terms of the skeleton displacement and the acoustic pressure in the interstitial fluid. It generalizes the previous formulation proposed by Professor Atalla & Co-authorsand has the great advantage over existing formulations of automatically satisfying all boundary conditions without having to compute surface coupling integrals at porous sub-domain interfaces. When elastic forces in the skeleton are neglected, the formulation automatically degenerates to an equivalent fluid model taking into account inertial coupling with the skeleton. This generalized mixed formulation and associated equivalent fluid model has been implemented by STRACO (France) in RAYON-PEM Solver. It is shown in this paper, that the numerical results predicted with RAYON-PEM agrees very well with experimental results using impedance tube tests and vibration measurements on multi-layered plates. | |||||
BibTeX:
@conference{Hamdi20001465, author = {Hamdi, M.A. and Mebarek, L. and Omrani, A. and Atalla, N.}, title = {An efficient formulation for the analysis of acoustic and elastic waves propagation in porous -elastic materials}, journal = {Proceedings of the 25th International Conference on Noise and Vibration Engineering, ISMA}, year = {2000}, pages = {1465-1470}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-13444261241&partnerID=40&md5=8614663df35d8b2dae2b810b78094012} } |
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Hamdi, M., Mebarek, L., Omrani, A. and Atalla, N. | Integration of acoustic absorbing porous components in vehicle environment using a novel finite element solver | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 24-28 |
article | URL |
Abstract: A new mixed finite element formulation very well adapted to analyze the propagation of elastic and acoustic waves in porous absorbing media is presented. The proposed new formulation is based on modified Biot's equations written in terms of the skeleton displacement and the acoustic pressure in the interstitial fluid. It generalizes the previous formulation proposed by Professor Atalla & Co-authors, and has the great advantage over existing formulations of automatically satisfying all boundary conditions without having to compute surface coupling integrals at porous sub-domain interfaces. When elastic forces in the skeleton are neglected, the formulation automatically degenerates to an equivalent fluid model taking into account inertial coupling with the skeleton. This generalized mixed formulation and associated equivalent fluid model has been implemented by STRACO (France) in RAYON-PEM Solver. It is shown in this paper, that the numerical results predicted with RAYON-PEM agrees very well with experimental results using impedance tube tests and vibration measurements on multi-layered plates. | |||||
BibTeX:
@article{Hamdi200024, author = {Hamdi, M.A. and Mebarek, L. and Omrani, A. and Atalla, N.}, title = {Integration of acoustic absorbing porous components in vehicle environment using a novel finite element solver}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {24-28}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034266709&partnerID=40&md5=3a77362d3474e0654fc2cdd7af1c2ab1} } |
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Kron, A., Roy, Y., Micheau, P., Bourassa, P. and Prince, F. | Motor control of posture using ?model: Validation of the model by experimentation [BibTeX] |
2000 | Archives of Physiology and Biochemistry Vol. 108(1-2), pp. 210 |
article | URL |
BibTeX:
@article{Kron2000210, author = {Kron, A. and Roy, Y. and Micheau, P. and Bourassa, P. and Prince, F.}, title = {Motor control of posture using ?model: Validation of the model by experimentation}, journal = {Archives of Physiology and Biochemistry}, year = {2000}, volume = {108}, number = {1-2}, pages = {210}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033768237&partnerID=40&md5=6ab20c952dc29aacca2dc4bf009ee23f} } |
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Lanctot, B., Panneton, R. and Atalla, N. | Errors and uncertainties of classical standing wave tube methods: SWR, TMTC and TMTM | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 86-87 |
article | URL |
Abstract: An analysis on three classical standing wave tube methods is presented to compare the precision and identifying the sensitive parameters. The studied methods are standard wave ratio (SWR), two microphone three calibration method (TMTC), two microphone transfer method (TMTM). A differential formulation is used to evaluate the errors and uncertainties on each of the methods. The porous test sample is modeled as an equivalent fluid using the Johnson-Champoux-Allard model. The results obtained for the 25 mm thick polyamide foam are described. | |||||
BibTeX:
@article{Lanctot200086, author = {Lanctot, B. and Panneton, R. and Atalla, N.}, title = {Errors and uncertainties of classical standing wave tube methods: SWR, TMTC and TMTM}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {86-87}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034268616&partnerID=40&md5=d4afaffb8fa2a00c9e50c5aaa7bcdad3} } |
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Langlois, C. and Panneton, R. | A method for the mechanical characterisation of poroelastic materials [BibTeX] |
2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 82-83 |
article | URL |
BibTeX:
@article{Langlois200082, author = {Langlois, C. and Panneton, R.}, title = {A method for the mechanical characterisation of poroelastic materials}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {82-83}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034268745&partnerID=40&md5=1756a8e7a88523f542c0f3870ea4a704} } |
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Leboucher, E., Micheau, P. and Berry, A. | Index to predict the stability of decentralized adaptive feedback active noise control system | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 60-61 |
article | URL |
Abstract: A decentralized adaptive feedback control system of periodic noise is developed for control of periodic disturbances. The stability of feedback loop and the stability of the control is effectuated in the frequency domain. A condition derived from the Nyquist criterion is given in order to predict the stability of the control. The results show that the positions of the control filters on their convergence path play an important role on the stability and the performance of the control system. | |||||
BibTeX:
@article{Leboucher200060, author = {Leboucher, E. and Micheau, P. and Berry, A.}, title = {Index to predict the stability of decentralized adaptive feedback active noise control system}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {60-61}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034266576&partnerID=40&md5=1976849d3681f09eb0a6562a478bbb6a} } |
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Masson, P. and Berry, A. | Comparison of several strategies in the active structural acoustic control using structural strain measurements | 2000 | Journal of Sound and Vibration Vol. 233(4), pp. 707-726 |
article | URL |
Abstract: Two optimized approaches are herein proposed to lighten the real-time computation of the radiated acoustic power from planar structures using discrete strain measurements. These approaches are compared to a reference approach involving finite differences reconstruction of the displacement field from the strain field. The first optimized approach allows the direct calculation of the radiated acoustic power from the discrete strain field while the second optimized approach employs an accelerated evaluation of the radiated acoustic power based on a wavelet transform of the displacement field. The evaluation of the radiated acoustic power from discrete strain values is experimentally assessed using the reference finite differences approach and both optimized approaches. Piezoelectric film (PVDF) strain sensors are used for this validation as well as a feedforward filtered-X LMS controller. Details on the real-time implementation of the cost functions are presented, especially on the off-line adaptation of the control filter. Formal comparisons using acoustic and vibration measurements are presented to better illustrate the control performance and mechanism of the different approaches. Experimental results serve to demonstrate the interest of using the optimized approaches as compared to the reference approach and it is shown that a significant gain in computational burden can be obtained using the proposed optimized approaches without sacrificing the control performance. | |||||
BibTeX:
@article{Masson2000707, author = {Masson, P. and Berry, A.}, title = {Comparison of several strategies in the active structural acoustic control using structural strain measurements}, journal = {Journal of Sound and Vibration}, year = {2000}, volume = {233}, number = {4}, pages = {707-726}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033706031&partnerID=40&md5=33e23fb385047891953f941c961e69a4} } |
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Mencik, J., Berry, A. and Guyader, J. | Formulation of an equation of diffusion for heterogeneous rods | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 114-115 |
article | URL |
Abstract: The vibratory behavior of heterogeneous structures was characterized considering the heterogeneity density and the high frequency. Statistical energy analysis (SEA) was used to characterize mean energies of lightly coupled subsystems. The energy flow method is based on the derivation of the equation of diffusion for homogeneous structures. The theoretical results were validated by a numerical simulation for a heterogeneous rod excited by a power source. | |||||
BibTeX:
@article{Mencik2000114, author = {Mencik, J.M. and Berry, A. and Guyader, J.L.}, title = {Formulation of an equation of diffusion for heterogeneous rods}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {114-115}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034264715&partnerID=40&md5=8a2151f3e3f78d9cb67a44f0a27d2ffa} } |
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Micheau, P. and Coirault, P. | Adaptive controller using filter banks to reject multi-sinusoidal disturbance | 2000 | Automatica Vol. 36(11), pp. 1659-1664 |
article | DOI URL |
Abstract: The purpose of this paper is to apply filter banks to the control problem involving the rejection of multi-sinusoidal disturbance from output of slowly time-varying stable systems. The use of filter banks allows to distribute the control effort in many independent adaptive controllers, each of them taking care of a sinusoidal component of the disturbance. By varying the filter banks specifications, the method handles the trade-off between a time-behavior controller, with interesting settling time and a tonal-behavior controller showing the properties of simplified control, reduced computational time and on-line system identification with the system output noise via the feedback loop. Numerical examples are presented to illustrate this trade-off. | |||||
BibTeX:
@article{Micheau20001659, author = {Micheau, P. and Coirault, P.}, title = {Adaptive controller using filter banks to reject multi-sinusoidal disturbance}, journal = {Automatica}, year = {2000}, volume = {36}, number = {11}, pages = {1659-1664}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034325793&doi=10.1016%2fS0005-1098%2800%2900072-8&partnerID=40&md5=d521f9b9b2332f3dc061070557d914dd}, doi = {https://doi.org/10.1016/S0005-1098(00)00072-8} } |
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Nadeau, S. and Champoux, Y. | Application of the direct complex stiffness method to engine mounts | 2000 | Experimental Techniques Vol. 24(3), pp. 21-23 |
article | DOI URL |
Abstract: The dynamic complex stiffness of engine mounts is a fundamental information for an effective vibration isolation design or prediction. In this paper, the know-how to use the direct complex stiffness method to measure engine mounts dynamic stiffness is presented. The theoretical background of the technique is disclosed, and two simple test benches for engine mounts axial and lateral stiffness measurements are described. Furthermore, a case study on an engine mount is presented in order to highlight the technical problems and limitations one can encounter in the practical implementation of the technique. | |||||
BibTeX:
@article{Nadeau200021, author = {Nadeau, S. and Champoux, Y.}, title = {Application of the direct complex stiffness method to engine mounts}, journal = {Experimental Techniques}, year = {2000}, volume = {24}, number = {3}, pages = {21-23}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034188014&doi=10.1111%2fj.1747-1567.2000.tb00906.x&partnerID=40&md5=d615808fef96b76d21e5308db94bbc12}, doi = {https://doi.org/10.1111/j.1747-1567.2000.tb00906.x} } |
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Nicolas, J. | Innovation and acoustic | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 10-11 |
article | URL |
Abstract: Innovation implies managing knowledge in a creative way in order to respond to the requests coming from the market and to other social needs. Communication and human interaction contribute a lot in this direction. Innovation provides a great challenge for the acousticians from enterprises, universities and public surroundings. | |||||
BibTeX:
@article{Nicolas200010, author = {Nicolas, J.}, title = {Innovation and acoustic}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {10-11}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034264809&partnerID=40&md5=1968c5f22facb324582f02d0ffcbb1f4} } |
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Renault, S., Rymeyko, F. and Berry, A. | Active noise control in enclosure with virtual microphone [BibTeX] |
2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 72-73 |
article | URL |
BibTeX:
@article{Renault200072, author = {Renault, S. and Rymeyko, F. and Berry, A.}, title = {Active noise control in enclosure with virtual microphone}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {72-73}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034268776&partnerID=40&md5=449d4190378fc5b990bee81623bfe9a7} } |
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Rigobert, S., Sgard, F. and Atalla, N. | Modeling of multilayered structures including porous materials using hierarchical elements and non coincident meshes | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 32-33 |
article | URL |
Abstract: The coupling of mixed displacement-pressure formulation using hierarchical elements with a finite element plate modeling of an elastic domain assuming non-coincident meshes can be done. It can be used to predict the mean quadratic velocity and the transmission loss of a plate coated with porous materials. The results are very accurate and are with a reduced number of unknowns as compared to classical finite element modeling of the structure with the coincident meshes. | |||||
BibTeX:
@article{Rigobert200032, author = {Rigobert, S. and Sgard, F. and Atalla, N.}, title = {Modeling of multilayered structures including porous materials using hierarchical elements and non coincident meshes}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {32-33}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034264728&partnerID=40&md5=bc9201d99fdcff56cb1efe650d3e04eb} } |
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Sgard, F., Atalla, N. and Nicolas, J. | A numerical model for the low frequency diffuse field sound transmission loss of double-wall sound barriers with elastic porous linings | 2000 | Journal of the Acoustical Society of America Vol. 108(6), pp. 2865-2872 |
article | DOI URL |
Abstract: This paper discusses the prediction of the low frequency diffuse field transmission loss through double-wall sound barriers with elastic porous linings. The studied sound barriers are made up from a porous-elastic decoupling material sandwiched between an elastic skin and a septum. The prediction approach is based on a finite element model for the different layers of the sound barrier coupled to a variational boundary element method to account for fluid loading. The diffuse field is modeled as a combination of uncorrelated freely propagating plane waves with equal amplitude, no two of which are traveling in the same direction. The corresponding vibroacoustic indicators are calculated efficiently using a Gauss integration scheme. Also, a power balance is presented to explain the dissipation mechanisms in the different layers. Typical results showing the effects on the transmission loss of several parameters such as the septum mass, the decoupling porous layer properties and the multi-layer mounting conditions are presented. (C) 2000 Acoustical Society of America. | |||||
BibTeX:
@article{Sgard20002865, author = {Sgard, F.C. and Atalla, N. and Nicolas, J.}, title = {A numerical model for the low frequency diffuse field sound transmission loss of double-wall sound barriers with elastic porous linings}, journal = {Journal of the Acoustical Society of America}, year = {2000}, volume = {108}, number = {6}, pages = {2865-2872}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033663872&doi=10.1121%2f1.1322022&partnerID=40&md5=1b73b487d699db402dcd65e5b96c023b}, doi = {https://doi.org/10.1121/1.1322022} } |
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Sgard, F. and Atalla, N. | Transmission loss through barriers lined with heterogeneous porous materials | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 92-93 |
article | URL |
Abstract: The effect of solid heterogeneities and acoustic cavities on the normal incidence transmission loss of heterogeneous porous materials inserted in an infinite rectangular waveguide is investigated. The model is based on a finite element Biot-Allard's formulation for the porous patches. The modal behavior of the waveguide accounts for the coupling between the porous material and the waveguide. Numerical results are presented regarding the effect of geometric and physical parameters on the transmission loss performance of highly resistive plastic foam. | |||||
BibTeX:
@article{Sgard200092, author = {Sgard, F.C. and Atalla, N.}, title = {Transmission loss through barriers lined with heterogeneous porous materials}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {92-93}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034268258&partnerID=40&md5=a7b911292e0c7337970dbf73ad0aab83} } |
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Sow, I., Beslin, O. and Nicolas, J. | Characterization of multi-layered panels mechanical properties | 2000 | Canadian Acoustics - Acoustique Canadienne Vol. 28(3), pp. 84-85 |
article | URL |
Abstract: A method which uses a simple experimental setup and a fast numerical code running on a personal computer is presented. Extraction of equivalent properties of small rectangular composite panels in terms of young's modulus, density and damping factor is possible. The measurement part of this hybrid method consist on a clamp fixture. The plate is excited by an electro-dynamic shaker and its mean quadratic velocity is measured. | |||||
BibTeX:
@article{Sow200084, author = {Sow, I. and Beslin, O. and Nicolas, J.}, title = {Characterization of multi-layered panels mechanical properties}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {2000}, volume = {28}, number = {3}, pages = {84-85}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034269204&partnerID=40&md5=1fdebae2416587f3fe6f46031eac4893} } |
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Tournour, M. and Atalla, N. | Pseudostatic corrections for the forced vibroacoustic response of a structure-cavity system | 2000 | Journal of the Acoustical Society of America Vol. 107(5 I), pp. 2379-2386 |
article | DOI URL |
Abstract: The analysis of the coupled vibroacoustic behavior of a structure-cavity system is often performed using the in vacuo structure modes and the rigid cavity modes. Unfortunately, the use of such a modal basis can result in a poor convergence when the high-frequency modes of one of the two subsystems are coupled to the low-frequency modes of the other subsystem. This problem is made critical by the lack of a reliable criterion for selecting the number of kept modes for each subsystem. This paper shows that the effect of modal truncation is critical for the convergence of the method and that the convergence can be greatly improved using pseudostatic corrections for both the structure and the cavity. The theory behind the proposed technique is presented together with two generic problems exhibiting strong coupling: (i) an elastic cylindrical cavity filled with air; and (ii) an elastic plate coupled to a rectangular cavity filled with water. (C) 2000 Acoustical Society of America. | |||||
BibTeX:
@article{Tournour20002379, author = {Tournour, M. and Atalla, N.}, title = {Pseudostatic corrections for the forced vibroacoustic response of a structure-cavity system}, journal = {Journal of the Acoustical Society of America}, year = {2000}, volume = {107}, number = {5 I}, pages = {2379-2386}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034107432&doi=10.1121%2f1.428624&partnerID=40&md5=7208350a17d78d6023dd216d0f7bb787}, doi = {https://doi.org/10.1121/1.428624} } |
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Atalla, N., Winckelmans, G. and Sgard, F. | A multiple multipole expansion approach for predicting the sound power of vibrating structures | 1999 | Acustica Vol. 85(1), pp. 47-53 |
article | URL |
Abstract: A multiple multipole expansion algorithm to evaluate the sound field from a collection of volume or surface sources is presented. The algorithm combines the proper assembly of the different multipole expansion terms together with the proper choice of the spatial extent of each expansion to yield rapid and accurate evaluation of the far-field pressure. Integration of this field over a hemisphere surrounding the sources leads to the radiated power. A special emphasis is put on discussing error scales and developing, for the truncated multipole expansion (monopole + dipole + quadrupole), a non dimensional convergence criterion in terms of the source spatial extent. This convergence criterion allows for an optimized numerical implementation of the algorithm. The algorithm is applied to the evaluation of the radiation efficiency of a baffled rectangular plate. It is verified by comparison with classical computational techniques. Numerical results show good agreement with other techniques for problems with both low and high modal densities. For the plate's problem, the use of the first three terms in the expansion (= monopole, dipole and quadrupole), together with a novel numerical implementation in a multiple multipole expansion scheme, is seen to be more efficient than classical computational techniques. | |||||
BibTeX:
@article{Atalla199947, author = {Atalla, N. and Winckelmans, G. and Sgard, F.}, title = {A multiple multipole expansion approach for predicting the sound power of vibrating structures}, journal = {Acustica}, year = {1999}, volume = {85}, number = {1}, pages = {47-53}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0042854931&partnerID=40&md5=e2343c8e6f8b8fb62a6accccb1cef7a3} } |
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Berry, A., Qiu, X. and Hansen, C. | Near-field sensing strategies for the active control of the sound radiated from a plate | 1999 | Journal of the Acoustical Society of America Vol. 106(6), pp. 3394-3406 |
article | DOI URL |
Abstract: When designing an active control system to globally control the far- field sound radiation from a vibrating surface, a challenging problem is to properly define the near-field acoustic sensing strategy and the type of cost function to be minimized by the controller. The strategy of sensing and minimizing the near-field active intensity at discrete locations in the active control of free field radiation from a vibrating plate is investigated in this paper. The optimal minimization of the sum of the near-field, normal active sound intensities at the error sensor locations using acoustic control sources is derived for this problem, and the results obtained are compared to the minimization of the sum of the near-field squared pressures. Some of the difficulties associated with sound intensity minimization are pointed out. | |||||
BibTeX:
@article{Berry19993394, author = {Berry, A. and Qiu, X. and Hansen, C.H.}, title = {Near-field sensing strategies for the active control of the sound radiated from a plate}, journal = {Journal of the Acoustical Society of America}, year = {1999}, volume = {106}, number = {6}, pages = {3394-3406}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032761356&doi=10.1121%2f1.428193&partnerID=40&md5=6cee71c1d3b4269e0b086ee662885371}, doi = {https://doi.org/10.1121/1.428193} } |
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Debergue, P., Panneton, R. and Atalla, N. | Boundary conditions for the weak formulation of the mixed (u,p) poroelasticity problem | 1999 | Journal of the Acoustical Society of America Vol. 106(5), pp. 2383-2390 |
article | DOI URL |
Abstract: This paper presents the boundary conditions that apply to the weak integral formulation of the Biot mixed (u,p) poroelasticity equations. These boundary conditions are derived from the classical boundary conditions of the Biot displacement (u,U) poroelasticity equations. They are applied to the surface integrals of the associated weak form to account for exterior excitations, supports, and couplings with exterior elastic, acoustic, poroelastic media, and a septum. It will be shown that the derived boundary conditions for the (u,p) formulation lead to simpler finite element equations compared to those obtained from the (u,U) formulation. Finally, two numerical examples are presented to validate the poroelastic-septum coupling condition, and to highlight the limitations of the free edge condition on a poroelastic medium. | |||||
BibTeX:
@article{Debergue19992383, author = {Debergue, P. and Panneton, R. and Atalla, N.}, title = {Boundary conditions for the weak formulation of the mixed (u,p) poroelasticity problem}, journal = {Journal of the Acoustical Society of America}, year = {1999}, volume = {106}, number = {5}, pages = {2383-2390}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032738797&doi=10.1121%2f1.428075&partnerID=40&md5=616acd4d821e2c2a25ab4c02e72aa1fd}, doi = {https://doi.org/10.1121/1.428075} } |
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Foin, O., Nicolas, J. and Atalla, N. | An efficient tool for predicting the structural acoustic and vibration response of sandwich plates in light or heavy fluid | 1999 | Applied Acoustics Vol. 57(3), pp. 213-242 |
article | DOI URL |
Abstract: The vibroacoustics of a plate covered by a free or a constrained viscoelastic layer is analyzed in this article. A variational model, solved by the Rayleigh-Ritz method, is proposed for the case of a rectangular, baffled, simply supported multilayered plate immersed either in a light fluid or in a heavy fluid. In order to simplify the theoretical formulation, approximate assumptions are made regarding the calculation of the strain energy of the plate. These assumptions are inspired from Ungar's work on viscoelastically damped beam. They allow the equation of motion of the plate to be expressed in terms of one unknown displacement while most of the classical variational models use at least five unkown displacements. Hence, the size of the mass matrix and of the stiffness matrix are reduced and the computing time is decreased. The radiation of sound from the plate is rigorously calculated with the methods of Sandman and Nelisse which makes high frequencies attainable without convergence problems. Theoretical validations of the proposed model are made using a well-known mulilayered plate model. In addition, very precise experiment set up allows the measurement of the vibration response of two sandwich plates that reveal the precision of the proposed model and present the type of damping achievable with commercially available viscoelastic material. © 1998 Elsevier Science Ltd. All rights reserved. | |||||
BibTeX:
@article{Foin1999213, author = {Foin, O. and Nicolas, J. and Atalla, N.}, title = {An efficient tool for predicting the structural acoustic and vibration response of sandwich plates in light or heavy fluid}, journal = {Applied Acoustics}, year = {1999}, volume = {57}, number = {3}, pages = {213-242}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-9344226749&doi=10.1016%2fS0003-682X%2898%2900059-0&partnerID=40&md5=3c735121f716fe94ec5ffa99bc8be615}, doi = {https://doi.org/10.1016/S0003-682X(98)00059-0} } |
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Masson, P. and Berry, A. | Fabry-Perot strain sensors for noise control applications | 1999 | Proceedings of SPIE - The International Society for Optical Engineering Vol. 3668(I), pp. 235-243 |
conference | URL |
Abstract: The use of white-light interferometric multimode fiber-optic strain sensors is experimentally assessed within a new strategy involving discrete strain sensing for the active control of the radiated sound power. Each strain sensor uses a Fabry-Perot sensing interferometer and a Fizeau cross-correlation interferometer so that the output signal is directly related to the absolute measured strain. Two approaches are used to relate the radiated sound power to the structural strain. The first approach is based on the reconstruction of the transverse structural displacement field from the structural strain field using a finite differences scheme, and a wavenumber transformation of the structural displacement to obtain the radiated sound field; the second approach is based on an exact expression directly relating the radiated sound field to the wavenumber transform of the structural strain. In both approaches, the wavenumber transform is performed over the supersonic (radiating) components of the structural information. Both approaches for using the strain information are implemented into a multi-channel filtered-X LMS algorithm to perform the active control of the sound power radiated from the beam. Experimental results obtained using four strain sensors and both control approaches show that fiber-optic strain sensors and PVDF strain sensors provide similar and good control performance. | |||||
BibTeX:
@conference{Masson1999235, author = {Masson, Patrice and Berry, Alain}, title = {Fabry-Perot strain sensors for noise control applications}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {1999}, volume = {3668}, number = {I}, pages = {235-243}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032687094&partnerID=40&md5=85c5a2f36fef9a803491ff746e3283ae} } |
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Masson, P., Berry, A. and Morin, A. | Experiments on the use of fiber-optic strain sensors in active structural acoustic control | 1999 | Journal of Intelligent Material Systems and Structures Vol. 10(1), pp. 71-82 |
article | DOI URL |
Abstract: Among the sensors available for active control of noise, strain sensors are of great interest as they can eliminate the need for far-field acoustic sensors, such as microphones. Fiber-optic strain sensors are especially of interest because they are easily embeddable into composite materials. This paper aims at a validation of the use of Fabry-Perot fiber-optic strain sensors in active structural control strategies. Two control approaches based on the direct use of discrete strain sensing are herein employed for the minimization of the acoustic radiation from a vibrating beam. The first approach involves the direct minimization of the strain levels at discrete points on the beam. The second cost function is defined as the radiated acoustic power: it involves the beam's displacement reconstruction from the strain field and is expressed in the wavenumber domain. Proper concentration of the control effort is expected with the cost function defined in the wavenumber domain but experimental constraints do not allow to demonstrate this clearly. The use of fiber-optic sensors is first validated for both control approaches with respect to an optimal solution and the impact of both approaches on radiated acoustic power is presented. It is shown that optimal and controller solutions agree well on a wide frequency band with the exception of some discrepancies arising from real-time approximations and fiber-optic reading unit limitations. The control mechanism of both approaches is then highlighted through experimental results combining acoustic and vibration measurements. Finally, the control performance obtained using the fiber-optic sensors is compared with the control performance obtained using PVDF strain sensors and it is shown that fiber-optic sensors offer a comparable performance. | |||||
BibTeX:
@article{Masson199971, author = {Masson, P. and Berry, A. and Morin, A.}, title = {Experiments on the use of fiber-optic strain sensors in active structural acoustic control}, journal = {Journal of Intelligent Material Systems and Structures}, year = {1999}, volume = {10}, number = {1}, pages = {71-82}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0343244622&doi=10.1177%2f1045389X9901000108&partnerID=40&md5=2612137ec4f9ad5622a078a93242d88e}, doi = {https://doi.org/10.1177/1045389X9901000108} } |
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Nadeau, S., Champoux, Y. and Mongeau, L. | Trim and floor influence on vibrational response of an aircraft fuselage model | 1999 | Journal of Aircraft Vol. 36(3), pp. 591-595 |
article | DOI URL |
Abstract: The influence of the interior trim and the floor partition on the vibratory response of the physical model of an aircraft fuselage model was investigated experimentally. The one-third scale model faithfully replicated the salient structural features of a rear-engines aircraft fuselage. Detailed modal analysis of the green fuselage, i.e., the bare fuselage skin without any floor, trim, or lining, was first performed. The effects of adding a honeycomb floor partition, a sound-absorbing blanket, and a thin plastic interior lining on the modal parameters of the structure were then determined. It was found that the addition of the sound-absorbing blanket significantly increased the structure's modal damping coefficients for its first five modes of resonance. Notable changes in the structural response at higher frequencies were also observed. These results strongly suggest, in agreement with recent studies reported in the literature, that sound-absorbing blankets do add significant damping to the vibration response of the structure (in addition to absorbing sound energy from the cabin interior). These damping properties may be used advantageously for the optimal design of skin-damping aircraft noise-control treatments for minimal added weight, and minimal cost. | |||||
BibTeX:
@article{Nadeau1999591, author = {Nadeau, S. and Champoux, Y. and Mongeau, L.}, title = {Trim and floor influence on vibrational response of an aircraft fuselage model}, journal = {Journal of Aircraft}, year = {1999}, volume = {36}, number = {3}, pages = {591-595}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033132137&doi=10.2514%2f2.2475&partnerID=40&md5=6e9afe356e5604c4e35669776851d1a6}, doi = {https://doi.org/10.2514/2.2475} } |
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Rigobert, S., Atalla, N. and Sgard, F. | Numerical modeling of porous-elastic materials using hierachical elements [BibTeX] |
1999 | Canadian Acoustics - Acoustique Canadienne Vol. 27(3), pp. 68-69 |
article | URL |
BibTeX:
@article{Rigobert199968, author = {Rigobert, S. and Atalla, N. and Sgard, F.}, title = {Numerical modeling of porous-elastic materials using hierachical elements}, journal = {Canadian Acoustics - Acoustique Canadienne}, year = {1999}, volume = {27}, number = {3}, pages = {68-69}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0039442418&partnerID=40&md5=da0b071e87b2b13677085e785332a206} } |
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Tournour, M. and Atalla, N. | Efficient evaluation of the acoustic radiation using multipole expansion | 1999 | International Journal for Numerical Methods in Engineering Vol. 46(6), pp. 825-837 |
article | DOI URL |
Abstract: The variational boundary element method (VBEM) is widely used to compute the acoustic radiation of structures. The classical numerical implementation of the VBEM suffers from the computational cost associated with double surface integration. In a previous paper [1], the authors proposed a novel method, based on multipole expansions, to accelerate the double layer potential calculation for structures having a periodic mesh. This technique, while efficient, is still limited by the cost of computing the surface pressure from the double surface potential. This paper presents an acceleration technique, based on multipole expansion, that allies both efficiency and accuracy. Copyright © 1999 John Wiley & Sons, Ltd. | |||||
BibTeX:
@article{Tournour1999825, author = {Tournour, M.A. and Atalla, N.}, title = {Efficient evaluation of the acoustic radiation using multipole expansion}, journal = {International Journal for Numerical Methods in Engineering}, year = {1999}, volume = {46}, number = {6}, pages = {825-837}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032655365&doi=10.1002%2f%28SICI%291097-0207%2819991030%2946%3a6%3c825%3a%3aAID-NME697%3e3.0.CO%3b2-2&partnerID=40&md5=dbfd84cb0c460d9c476e8152824960f2}, doi = {https://doi.org/10.1002/(SICI)1097-0207(19991030)46:6%3C825::AID-NME697%3E3.0.CO;2-2} } |
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Atalla, N., Panneton, R. and Debergue, P. | A mixed displacement-pressure formulation for poroelastic materials | 1998 | Journal of the Acoustical Society of America Vol. 104(3 I), pp. 1444-1452 |
article | DOI URL |
Abstract: Recently, finite element models based on Biot's displacement (u,U) formulation for poroelastic materials have been extensively used to predict the acoustical and structural behavior of multilayer structures. These models while accurate lead to large frequency dependent matrices for three- dimensional problems necessitating important setup time, computer storage and solution time. In this paper, a novel exact mixed displacement pressure (u,p) formulation is presented. The formulation derives directly from Biot's poroelasticity equations. It has the form of a classical coupled fluid- structure problem involving the dynamic equations of the skeleton in vacuo and the equivalent fluid in the rigid skeleton limit. The governing (u,p) equations and their weak integral form are given together with the coupling conditions with acoustic media. The numerical implementation of the presented approach in a finite element code is discussed. Examples are presented to show the accuracy and effectiveness of the presented formulation. | |||||
BibTeX:
@article{Atalla19981444, author = {Atalla, N. and Panneton, R. and Debergue, P.}, title = {A mixed displacement-pressure formulation for poroelastic materials}, journal = {Journal of the Acoustical Society of America}, year = {1998}, volume = {104}, number = {3 I}, pages = {1444-1452}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031690348&doi=10.1121%2f1.424355&partnerID=40&md5=dc393da7d600b0612e56552552e790f5}, doi = {https://doi.org/10.1121/1.424355} } |
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Atalla, N., Panneton, R. and Debergue, P. | Numerical modeling of the vibroacoustic behavior of multilayer structures with poroelastic materials | 1998 | Proceedings - National Conference on Noise Control Engineering, pp. 611-614 | conference | URL |
Abstract: The bases of a numerical simulation tool that can assist engineers in designing multilayer composite structures encountered in the automobile, aeronautic, space and train industries are presented. This simulation tool can be used to reduce the number of costly experimental tests and to optimize the vibroacoustic design of multilayer panels. Numerical results showed the usefulness of the simulation tool to analyze the vibroacoustic behavior of realistic configurations in the whole audible frequency range. Further numerical simulations applied to more realistic configurations such as aircraft panels and train panels are presented together with its validation. | |||||
BibTeX:
@conference{Atalla1998611, author = {Atalla, Noureddine and Panneton, Raymond and Debergue, Patricia}, title = {Numerical modeling of the vibroacoustic behavior of multilayer structures with poroelastic materials}, journal = {Proceedings - National Conference on Noise Control Engineering}, year = {1998}, pages = {611-614}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031626352&partnerID=40&md5=08891075736d71e27b242e2dd9c0d074} } |
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Atalla, N. and Tournour, M. | Investigation of accelerating technique for the variational boundary element method based on multipole expansions | 1998 | Proceedings of the 23rd International Conference on Noise and Vibration Engineering, ISMA, pp. 675-681 | conference | URL |
Abstract: In this paper, the variational boundary element method (VBEM) is used to compute the acoustic radiation of structures with Neumann's boundary condition. The classical numerical implementation of the VBEM suffers from the computation cost associated with double surface integration. A novel method, based on multipole expansions, is proposed to alleviate this limitation and accelerate the double layer potential calculation for structure having a periodic mesh. For additional time savings, the technique is extended to the calculation of the pressure from the double layer potential. | |||||
BibTeX:
@conference{Atalla1998675, author = {Atalla, N. and Tournour, M.A.}, title = {Investigation of accelerating technique for the variational boundary element method based on multipole expansions}, journal = {Proceedings of the 23rd International Conference on Noise and Vibration Engineering, ISMA}, year = {1998}, pages = {675-681}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-13444273096&partnerID=40&md5=e069dbf582fff052ac9def0094bd0823} } |
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Champoux, Y. | Integrated course on the experimental method in engineering | 1998 | ASEE Annual Conference Proceedings, pp. 6pp | conference | URL |
Abstract: In 1996, the Mechanical Engineering Department of l'Universite de Sherbrooke introduced a new and progressive curriculum. A course entitled 'Experimental Method in Engineering' was developed to teach to the students how to solve technical problems using an experimental approach. The course was offered for the first time in the fall of 1997 to a class of 120 sophomores. The purpose of the course is threefold. First, it covers the basic knowledge associated to experimentation. Second, several laboratories are used to enhance the understanding of the courses content and to develop the students skills. Finally, the course is closely linked to a major semester experimental project. This paper presents a short description of the course content and how the course was designed. It also demonstrates that the course is an excellent 'integrator' that allows the students to link the knowledge covered in various courses. | |||||
BibTeX:
@conference{Champoux1998, author = {Champoux, Yvan}, title = {Integrated course on the experimental method in engineering}, journal = {ASEE Annual Conference Proceedings}, year = {1998}, pages = {6pp}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032303938&partnerID=40&md5=fd186073be265ed35604fc9d7cf1acf2} } |
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Charette, F., Berry, A. and Guigou, C. | Active control of sound radiation from a plate using a polyvinylidene fluoride volume displacement sensor | 1998 | Journal of the Acoustical Society of America Vol. 103(3), pp. 1493-1503 |
article | DOI URL |
Abstract: This paper presents a new volume displacement sensor (made of shaped strips of PVDF film) and the experimental implementation of this sensor in an active control system. A design strategy for a PVDF sensor detecting the volume displacement induced by a vibrating 2D structure is presented. It is based on the modal representation of the plate response. It actually consists in designing a PVDF sensor, composed of several shaped PVDF strips bonded to the surface of the structure, in such a way that the output signal of the sensor is directly proportional to the volume displacement. The design methodology is based on the experimental measurements of the plate mode shapes (eigenfunctions) and is valid for any type of boundary conditions. The experimental implementation of such a volumetric sensor in an of volume displacement sen obtained validates this new type of volume displacement sensor.
This paper presents a new volume displacement sensor (made of shaped strips of PVDF film) and the experimental implementation of this sensor in an active control system. A design strategy for a PVDF sensor detecting the volume displacement induced by a vibrating 2D structure is presented. It is based on the modal representation of the plate response. It actually consists in designing a PVDF sensor, composed of several shaped PVDF strips bonded to the surface of the structure, in such a way that the output signal of the sensor is directly proportional to the volume displacement. The design methodology is based on the experimental measurements of the plate mode shapes (eigenfunctions) and is valid for any type of boundary conditions. The experimental implementation of such a volumetric sensor in an active control system is then presented. The experimental results obtained validates this new type of volume displacement sensor. |
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BibTeX:
@article{Charette19981493, author = {Charette, F. and Berry, A. and Guigou, C.}, title = {Active control of sound radiation from a plate using a polyvinylidene fluoride volume displacement sensor}, journal = {Journal of the Acoustical Society of America}, year = {1998}, volume = {103}, number = {3}, pages = {1493-1503}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032032542&doi=10.1121%2f1.421301&partnerID=40&md5=500f3458b548b0ff9ec8ac91cabcaf78}, doi = {https://doi.org/10.1121/1.421301} } |
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Côté, A., Atalla, N. and Guyader, J.-L. | Vibroacoustic analysis of an unbaffled rotating disk | 1998 | Journal of the Acoustical Society of America Vol. 103(3), pp. 1483-1492 |
article | DOI URL |
Abstract: The dynamic and acoustic response of an unbaffled rotating disk, subjected to a space-fixed harmonic lateral force, is investigated. The plate is supposed to be clamped at the inside and free at the outer boundary. The exciting force being space-fixed, the mass and stiffness matrices, obtained from the variational method combined with the Rayleigh-Ritz approach in the rotating frame, are converted back to the nonrotating frame, where the generalized force and the displacements of the plate are evaluated. The related acoustic pressure, neglecting fluid loading, is determined using a boundary element formulation. Special attention has been given to ensure correct modeling of the unbaffled condition on the radiation of the plate. Results are presented to show the effect of rotation for both dynamic response and acoustic radiation. A practical case is also investigated: the circular saw. To simulate the exciting force of the saw, a measurement of the force induced by one tooth has been done. Then, a retarded-time sam has been performed to account for the exact number of teeth. | |||||
BibTeX:
@article{Côté19981483, author = {Côté, A.F. and Atalla, N. and Guyader, J.-L.}, title = {Vibroacoustic analysis of an unbaffled rotating disk}, journal = {Journal of the Acoustical Society of America}, year = {1998}, volume = {103}, number = {3}, pages = {1483-1492}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2642683202&doi=10.1121%2f1.421286&partnerID=40&md5=943fd722641723fcd8654bed24e51375}, doi = {https://doi.org/10.1121/1.421286} } |
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Dauchez, N., Sahraoui, S. and Atalla, N. | Vibroacoustic behavior of a porous layer bonded onto a plate | 1998 | 4th AIAA/CEAS Aeroacoustics Conference, pp. 823-826 | conference | DOI URL |
Abstract: Damping added by a poroelastic material on a vibrating plate is investigated. The goal is to understand dissipation mechanisms within the porous layer in order to optimize damping. This analysis is based on a 3-D finite element formulation including poroelastic elements. First, dissipated powers related to thermal, viscous and viscoelastic dissipation are explicited. Then a generic configuration (simply supported aluminium plate with a bonded porous layer and mechanical excitation) is studied. Thermal dissipation is found negligible. Viscous dissipation can be optimized as a function of air flow resistivity. It is the major phenomenon within glasswool materials, whereas viscoelastic dissipation is dominant for polymeric foams. Finaly, a model of equivalent plate is proposed. It includes shear in the porous layer and only viscoelasticity of the squeleton. Good results are found for foam materials. © 1998 by the Confederation of European Aerospace Societies. All rights reserved. | |||||
BibTeX:
@conference{Dauchez1998823, author = {Dauchez, N. and Sahraoui, S. and Atalla, N.}, title = {Vibroacoustic behavior of a porous layer bonded onto a plate}, journal = {4th AIAA/CEAS Aeroacoustics Conference}, year = {1998}, pages = {823-826}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977111832&doi=10.2514%2f6.1998-2346&partnerID=40&md5=e34015ca612d0961ff47a90a20f14ce9}, doi = {https://doi.org/10.2514/6.1998-2346} } |
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Gorog, S. and Micheau, P. | Filter banks implementation of numerical models for vibroacoustic analysis in the medium frequency range | 1998 | Journal of Sound and Vibration Vol. 213(1), pp. 35-54 |
article | DOI URL |
Abstract: A numerical method is proposed for predicting the vibroacoustic response of a viscoelastic structure submitted to harmonic forces in the medium frequency range. The structure is described as a finite dimension dynamical system. The frequency domain of interest is divided into several different subdomains. The method consists of solving a set of time domain equations of motion where each of them is associated with a given frequency subdomain. This time-frequency study is formulated within the framework of non-uniform modulated filter banks. Conditions are given to ensure that the analysis and the synthesis banks allow reconstruction of the complete investigated displacement field from the time solutions. A low-pass filter with a compact time support is designed to ensure an efficient computation. To illustrate the discussion, two examples using different variational approaches are proposed. First, flexural vibrations of an in vacuo steel plate described by a finite element method is considered. Second, a semi-analytical method is used to describe a point loaded steel plate radiating in air. © 1998 Academic Press Limited. | |||||
BibTeX:
@article{Gorog199835, author = {Gorog, S. and Micheau, P.}, title = {Filter banks implementation of numerical models for vibroacoustic analysis in the medium frequency range}, journal = {Journal of Sound and Vibration}, year = {1998}, volume = {213}, number = {1}, pages = {35-54}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038934592&doi=10.1006%2fjsvi.1997.1425&partnerID=40&md5=1efed08a6a3030516d470d3f75fb1379}, doi = {https://doi.org/10.1006/jsvi.1997.1425} } |
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Masson, P., Berry, A. and Micheau, P. | A wavelet approach to the active structural acoustic control | 1998 | Journal of the Acoustical Society of America Vol. 104(3 I), pp. 1453-1465 |
article | DOI URL |
Abstract: This paper presents a new cost function to be used in active control strategies, approximating the radiated acoustic power from a planar structure by a wavelet transform. This cost function is defined to be global, i.e., in terms of energy, and in the wave number domain to exploit the fact that only wave number components located in the supersonic region contribute to sound power radiation. It is shown that the wavelet transform of the transverse displacement field can provide an energy localization both in the supersonic region and spatially on the structure. Thus, the new cost function is defined as being representative of the radiated acoustic power and is obtained from a wavelet transform which depends solely on a scale parameter which is directly related to the frequency so that this representation extends over a broadband frequency range without requiring more than a single step, i.e., the wavelet transformation. The wavelet approach is compared to the radiated acoustic power from simply supported beams of finite and infinite width and very good agreement is obtained. Optimal control simulations are performed to validate the use of the wavelet transform as the cost function in an active control strategy. The performance obtained using the wavelet approach as the cost function compares advantageously with the performance obtained using the radiated acoustic power. | |||||
BibTeX:
@article{Masson19981453, author = {Masson, P. and Berry, A. and Micheau, P.}, title = {A wavelet approach to the active structural acoustic control}, journal = {Journal of the Acoustical Society of America}, year = {1998}, volume = {104}, number = {3 I}, pages = {1453-1465}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031687681&doi=10.1121%2f1.424356&partnerID=40&md5=7dd303a8c7d808d95e3e9df76a6e2e43}, doi = {https://doi.org/10.1121/1.424356} } |
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Mongeau, L., Han, F., Champoux, Y., Li, D. and Iacovoni, D. | Robust design of vehicle weather sealing systems for minimal sound transmission | 1998 | Proceedings - National Conference on Noise Control Engineering, pp. 217-222 | conference | URL |
Abstract: A systematic approach was followed to identify optimal vehicle weather seal configurations for low aerodynamic noise transmission. The frequency averaged noise reduction associated with several seal profiles and coatings was measured in a laboratory environment for a wide range of control factors and noise factors. Component tests using a fixture allowed a large number of configurations to be cost-effectively evaluated. The use of statistical methods to select the experimental configurations to be tested also reduced costs and efforts. | |||||
BibTeX:
@conference{Mongeau1998217, author = {Mongeau, Luc and Han, Fei and Champoux, Yvan and Li, Dingjun and Iacovoni, Don}, title = {Robust design of vehicle weather sealing systems for minimal sound transmission}, journal = {Proceedings - National Conference on Noise Control Engineering}, year = {1998}, pages = {217-222}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031637284&partnerID=40&md5=5cccc39fc30f2642e43b44fa2b7357d9} } |
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Nelisse, H., Beslin, O. and Nicolas, J. | A generalized approach for the acoustic radiation from a baffled or unbaffled plate with arbitrary boundary conditions, immersed in a light or heavy fluid | 1998 | Journal of Sound and Vibration Vol. 211(2), pp. 207-225 |
article | DOI URL |
Abstract: The present paper is dedicated to the study of the radiation of a baffled and/or unbaffled plate with arbitrary boundary conditions. The proposed work deals with a complete and rigorous fluid-structure coupling. A Rayleigh-Ritz approach is used to develop the plate deflection and, in the unbaffled case, the sound pressure jump function. A suitable set of trial functions is proposed. It allows to obtain only one generic numerical code for all the boundary conditions and - a key aspect of the formulation - for both the baffled and the unbaffled plate. An efficient numerical scheme is proposed for the computation of the radiation impedance coefficients. A good agreement is found with a numerical approach based on the boundary element method. Validation with experimental results is also presented. The present formulation provides a useful tool to perform a clear and systematic comparison between the baffled and the unbaffled plate. © 1998 Academic Press Limited. | |||||
BibTeX:
@article{Nelisse1998207, author = {Nelisse, H. and Beslin, O. and Nicolas, J.}, title = {A generalized approach for the acoustic radiation from a baffled or unbaffled plate with arbitrary boundary conditions, immersed in a light or heavy fluid}, journal = {Journal of Sound and Vibration}, year = {1998}, volume = {211}, number = {2}, pages = {207-225}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0000551246&doi=10.1006%2fjsvi.1997.1359&partnerID=40&md5=0113e8e37e73c5b5fb9d6ae90bc43f77}, doi = {https://doi.org/10.1006/jsvi.1997.1359} } |
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Panneton, R. and Atalla, N. | Computer simulations of multilayer panels with limp, rigid or elastic sound absorbing layers | 1998 | Proceedings - National Conference on Noise Control Engineering, pp. 621-626 | conference | URL |
Abstract: The use of finite element models to simulate sound absorbing materials used in multilayer panels is presented. Comparisons between the limitations of different models are discussed. The comparisons are in terms of absorption, transmission loss, and insertion loss. The results are obtained with the prediction code Maestro which is dedicated to vibroacoustic analysis of multilayer structures made up from elastic, viscoelastic, acoustic and sound absorbing materials. | |||||
BibTeX:
@conference{Panneton1998621, author = {Panneton, Raymond and Atalla, Noureddine}, title = {Computer simulations of multilayer panels with limp, rigid or elastic sound absorbing layers}, journal = {Proceedings - National Conference on Noise Control Engineering}, year = {1998}, pages = {621-626}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031640477&partnerID=40&md5=4847f7b46717e105a4d1aba7ada7541d} } |
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Ratle, A. and Berry, A. | Use of genetic algorithms for the vibroacoustic optimization of a plate carrying point-masses | 1998 | Journal of the Acoustical Society of America Vol. 104(6), pp. 3385-3397 |
article | DOI URL |
Abstract: Optimal design of mechanical structures for vibration or noise reduction often requires finding the minima of highly nonlinear multi-dimensional functions. In this paper, genetic algorithms are introduced as a new promising tool for numerical optimization of such problems. The application presented is on the control of the vibroacoustic response of a plate carrying point-masses. Genetic algorithms have been used to determine the optimal positions of the masses on the plate. Several cases are presented, using various optimization criteria, showing the importance of selecting the most appropriate criterion.
Genetic algorithms (GAs) are presented in the context of structural design optimization for vibroacoustic reduction. It is shown that the use of such an optimization procedure can help in finding original solutions that would not be found with intuitive means. GAs are well-suited for vibroacoustics problems for their ability to deal with highly irregular functions. The performance of the GAs is illustrated through numerical testing on a rectangular plate carrying up to five point-masses. |
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BibTeX:
@article{Ratle19983385, author = {Ratle, A. and Berry, A.}, title = {Use of genetic algorithms for the vibroacoustic optimization of a plate carrying point-masses}, journal = {Journal of the Acoustical Society of America}, year = {1998}, volume = {104}, number = {6}, pages = {3385-3397}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032432358&doi=10.1121%2f1.423922&partnerID=40&md5=d859ee271d6baed1876b4c128f53c7d8}, doi = {https://doi.org/10.1121/1.423922} } |
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Tournour, M. and Atalla, N. | A novel acceleration method for the variational boundary element approach based on multipole expansion | 1998 | International Journal for Numerical Methods in Engineering Vol. 42(7), pp. 1199-1214 |
article | DOI URL |
Abstract: The acoustic radiation of general structures with Neumann's boundary condition using Variational Boundary Element Method (VBEM) is considered. The classical numerical implementation of the VBEM suffers from the computation cost associated with double surface integration. To alleviate this limitation, a novel acceleration method is proposed. The method is based on the expansion of the cross influence matrices in terms of multipoles using the expansion of the Green's function in terms of spherical Bessel functions. Since the resulting multipoles are not dependent on the elements locations, large computation time savings are achieved. Moreover, it is shown that by accounting for the monopole, dipole and quadrupole terms in the multipole expansion, the classical convergence criteria usually used in boundary element guarantee convergence of the proposed method. Several numerical examples are presented to demonstrate the efficiency and accuracy of the proposed method. © 1998 John Wiley & Sons, Ltd. | |||||
BibTeX:
@article{Tournour19981199, author = {Tournour, M.A. and Atalla, N.}, title = {A novel acceleration method for the variational boundary element approach based on multipole expansion}, journal = {International Journal for Numerical Methods in Engineering}, year = {1998}, volume = {42}, number = {7}, pages = {1199-1214}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032136142&doi=10.1002%2f%28SICI%291097-0207%2819980815%2942%3a7%3c1199%3a%3aAID-NME405%3e3.0.CO%3b2-S&partnerID=40&md5=f8baedf26f8144917ea65c0e0ea46dce}, doi = {https://doi.org/10.1002/(SICI)1097-0207(19980815)42:7%3C1199::AID-NME405%3E3.0.CO;2-S} } |
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Tournour, M.A. and Atalla, N. | Optimization design for stiffeners using component mode synthesis | 1998 | Proceedings - National Conference on Noise Control Engineering, pp. 331-334 | conference | URL |
Abstract: A free interface component mode synthesis approach is demonstrated for fast and accurate parametric study of stiffener design. The method's theoretical foundation is discussed, and the method is validated by comparison with a classical finite element approach using stiffened plates. The influence of the number of kept modes, and of the number and location of the stiffeners in the substructure analysis is studied. Furthermore, the influence on acoustic and vibration indicators is examined. | |||||
BibTeX:
@conference{Tournour1998331, author = {Tournour, Michel A. and Atalla, Noureddine}, title = {Optimization design for stiffeners using component mode synthesis}, journal = {Proceedings - National Conference on Noise Control Engineering}, year = {1998}, pages = {331-334}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031636023&partnerID=40&md5=5bd99ca82fac2139e6f40c43a0cb2f17} } |
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Tournour, M. and Atalla, N. | Vibroacoustic behavior of an elastic box using state-of-the-art FEM-BEM approaches | 1998 | Noise Control Engineering Journal Vol. 46(3), pp. 83-90 |
article | DOI URL |
Abstract: State-of-the-art methods for the study of the vibroacoustic response of a rectangular box are presented. Fast and accurate approaches are used for structural modeling, cavity coupling, and acoustic radiation modeling. A free interface component mode synthesis is used for the modal analysis of the box. The structural modes are then coupled to the cavity modes using a modal superposition technique. For radiation from the box, an indirect variational formulation is developed in terms of surface integral equations. A special integration scheme is used to handle singularities of the Green's function. In order to reduce significantly the computation time of the regular integrals, a new method based on expansion of the Green's function and its normal derivative in terms of spherical Bessel functions is used. The techniques presented are validated and the results for a typical box problem are presented. © 1998 Institute of Noise Control Engineering. | |||||
BibTeX:
@article{Tournour199883, author = {Tournour, M. and Atalla, N.}, title = {Vibroacoustic behavior of an elastic box using state-of-the-art FEM-BEM approaches}, journal = {Noise Control Engineering Journal}, year = {1998}, volume = {46}, number = {3}, pages = {83-90}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032064644&doi=10.3397%2f1.2828460&partnerID=40&md5=33836d5e80abbf63507106dd1af701a7}, doi = {https://doi.org/10.3397/1.2828460} } |
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Amédin, C., Champoux, Y. and Berry, A. | Acoustical characterization of absorbing porous materials through transmission measurements in a free field | 1997 | Journal of the Acoustical Society of America Vol. 102(4), pp. 1982-1993 |
article | DOI URL |
Abstract: Various results are presented to experimentally validate the theoretical modeling of the acoustic radiation of a circular piston through a thin layer of porous absorbing material, as worked out by Amedin et al. [J. Acoust. Sec. Am. 98, 1757-1766 (1995)]. This theoretical modeling is subsequently exploited for the development of an acoustical characterization method for porous absorbing materials. The method is based on acoustical pressure measurements taken at two different positions in an open baffled tube radiating into the material to be characterized and at a given point above the material, and on an iterative process of numerical resolution. The reliability of the method is evaluated by means of numerical simulations and by comparisons using the two-layer method in an impedance tube [J. Acoust. Soc. Am. 74, 1577-1582 (1983)]. The preliminary tests show that the new method can be used to experimentally characterize the specific acoustic impedance and the propagation constant of porous absorbing materials. Its use will be possible for the acoustical characterization of porous absorbing materials in situ. | |||||
BibTeX:
@article{Amédin19971982, author = {Amédin, C.K. and Champoux, Y. and Berry, A.}, title = {Acoustical characterization of absorbing porous materials through transmission measurements in a free field}, journal = {Journal of the Acoustical Society of America}, year = {1997}, volume = {102}, number = {4}, pages = {1982-1993}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030829595&doi=10.1121%2f1.419689&partnerID=40&md5=daa5f68edd7d85f3e1b0eaf7ba575a5c}, doi = {https://doi.org/10.1121/1.419689} } |
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Atalla, N., Panneton, R. and Allard, J.-F. | Sound absorption by nonhomogeneous thin porous layers | 1997 | Journal of the Acoustical Society of America Vol. 102(5), pp. 3145 |
article | DOI URL |
Abstract: Sound absorption and sound transmission of nonhomogeneous porous materials made of random or regular arrays of porous media is investigated using the finite-element method. The configuration studied consists of a column of porous materials inserted in an infinite rectangular waveguide. In the finite-element model, an equivalent fluid model for the porous material is coupled to the modal behavior in the waveguide. By comparison with analytical calculations, the difference between absorption mechanisms in three-dimensional porous patchworks and simpler stratified materials is investigated. In particular, the importance of nonpropagative mechanisms is enlightened. Also, the transmission loss performance of nonhomogeneous porous materials compared to homogeneous porous material is discussed. © 1997, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Atalla19973145, author = {Atalla, N. and Panneton, R. and Allard, J.-F.}, title = {Sound absorption by nonhomogeneous thin porous layers}, journal = {Journal of the Acoustical Society of America}, year = {1997}, volume = {102}, number = {5}, pages = {3145}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85024781345&doi=10.1121%2f1.420691&partnerID=40&md5=379cc0991b2135d6cc6233d4d1f9291a}, doi = {https://doi.org/10.1121/1.420691} } |
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Atalla, M., Panneton, R. and Allard, J.-F. | Sound absorption by non homogeneous thin porous layers | 1997 | Acustica Vol. 83(5), pp. 891-896 |
article | URL |
Abstract: Sound absorption by non homogeneous porous materials made up of random or regular arrays of porous media is calculated by two methods based upon a simple modeling of the acoustic field, and by the finite element method. The difference between absorption mechanisms in three-dimensional porous patchworks and simpler stratified materials is investigated. The importance of non-propagative mechanisms in sound absorption is enlightened. | |||||
BibTeX:
@article{Atalla1997891, author = {Atalla, M. and Panneton, R. and Allard, J.-F.}, title = {Sound absorption by non homogeneous thin porous layers}, journal = {Acustica}, year = {1997}, volume = {83}, number = {5}, pages = {891-896}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031220618&partnerID=40&md5=a71f0245b9165bf14448b3601c5caa88} } |
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Beslin, O. and Nicolas, J. | A hierarchical functions set for predicting very high order plate bending modes with any boundary conditions | 1997 | Journal of Sound and Vibration Vol. 202(5), pp. 633-655 |
article | DOI URL |
Abstract: In this paper a new hierarchical functions set is proposed to predict flexural motion of plate-like structures in the medium frequency range. This functions set is built from trigonometric functions instead of polynomials as classically encountered in the literature. It is shown that such a trigonometric set presents all the advantages of a classical hierarchical polynomials set and additional ones which are of interest if very high order functions are intended to be used. It is stated that this new trigonometric set can be used at very high orders, up to 2048 without taking care of computer round-off errors, while the polynomials set fail, at order 46 because of the limited numerical dynamics of computers. This trigonometric set can be easily implemented on a computer. It does not require quadruple precision pre-computed arrays. Only a very low number (which does not depend on the function order) of basic operations is needed when calling such functions. Moreover, it is shown that this trigonometric set presents a better convergence rate than polynomials when predicting high order natural flexural modes of rectangular plates with any boundary conditions. © 1997 Academic Press Limited. | |||||
BibTeX:
@article{Beslin1997633, author = {Beslin, O. and Nicolas, J.}, title = {A hierarchical functions set for predicting very high order plate bending modes with any boundary conditions}, journal = {Journal of Sound and Vibration}, year = {1997}, volume = {202}, number = {5}, pages = {633-655}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031146158&doi=10.1006%2fjsvi.1996.0797&partnerID=40&md5=1b427704058f0be75c802d5405309382}, doi = {https://doi.org/10.1006/jsvi.1996.0797} } |
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Charette, F., Berry, A. and Guigou, C. | Dynamic effects of piezoelectric actuators on the vibrational response of a plate | 1997 | Journal of Intelligent Material Systems and Structures Vol. 8(6), pp. 513-524 |
article | DOI URL |
Abstract: This paper presents an analytical model and an experimental study for the response of plates actuated by piezoceramic elements. The variational approach with Hamilton's principle is used to develop the analytical model. This formulation, which is energy based, allows to consider any boundary conditions at the edges of the plate and to take into account the dynamic effects (mass loading and stiffness) of the piezoelectric actuators on the plate response. The ratio between the piezoelectric actuator mass and the plate mass considered in this work is small (less than 0.5%). Nevertheless, the model and the experiments demonstrate that the dynamic coupling between the piezoelectric actuators and the plate slightly modifies the plate modes. These structural modifications are apparent in some vibrational indicators, such as the displacement at the center of the plate and the volume dis-placement induced by the plate. | |||||
BibTeX:
@article{Charette1997513, author = {Charette, F. and Berry, A. and Guigou, C.}, title = {Dynamic effects of piezoelectric actuators on the vibrational response of a plate}, journal = {Journal of Intelligent Material Systems and Structures}, year = {1997}, volume = {8}, number = {6}, pages = {513-524}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031152447&doi=10.1177%2f1045389X9700800604&partnerID=40&md5=9a79c9fd0f26356553e8145020095bac}, doi = {https://doi.org/10.1177/1045389X9700800604} } |
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Cote, A., Atalla, N. and Nicolas, J. | Effects of shear deformation and rotary inertia on the free vibration of a rotating annular plate | 1997 | Journal of Vibration and Acoustics, Transactions of the ASME Vol. 119(4), pp. 641-643 |
article | DOI URL |
Abstract: This Tech Brief addresses the effects of shear deformation and rotary inertia on the free vibration of a rotating annular plate. Several studies have been done to understand these effects (trie et al, 1982; Sinha, 1987). in particular, the importance of these terms is well biown for disks with a thickness ratio h/a > 0.05 where h is the thickness of the disk and a is its outer radius. However, there is a need to show how they affect the disk vibration as the thickness ratio increases. It is well accepted that shear deformation and rotary inertia should be included in the analysis when h/a > 0.05 (Batoz and Ohatt, 1990). However, this Tech Brief will show that this criterion is not valid for all the modes. It will present the evolution of the number of modes correctly evaluated versus the thickness ratio, and, finally, will give a heuristic criterion to predict when it is necessary to consider shear deformation and rotary inertia © 1997 by ASME. | |||||
BibTeX:
@article{Cote1997641, author = {Cote, A. and Atalla, N. and Nicolas, J.}, title = {Effects of shear deformation and rotary inertia on the free vibration of a rotating annular plate}, journal = {Journal of Vibration and Acoustics, Transactions of the ASME}, year = {1997}, volume = {119}, number = {4}, pages = {641-643}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031248477&doi=10.1115%2f1.2889775&partnerID=40&md5=4bcafa0e2d328f526e1738760bba8179}, doi = {https://doi.org/10.1115/1.2889775} } |
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Gorog, S., Panneton, R. and Atalla, N. | Mixed displacement-pressure formulation for acoustic anisotropic open porous media | 1997 | Journal of Applied Physics Vol. 82(9), pp. 4192-4196 |
article | DOI URL |
Abstract: This article presents a general mixed displacement-pressure formulation to analyze the dynamic behavior of anisotropic open porous materials. This formulation is obtained in the time domain without neglecting the acceleration terms related to the fluid phase of the porous medium. The derivation of the presented formulation uses Coussy's description of porous materials. Forisotropic media and harmonic motions, the developed general mixed formulation reduces to the common set of equations of motion used in acoustics which results directly from Biot's equations. © 1997 American Institute of Physics. | |||||
BibTeX:
@article{Gorog19974192, author = {Gorog, S. and Panneton, R. and Atalla, N.}, title = {Mixed displacement-pressure formulation for acoustic anisotropic open porous media}, journal = {Journal of Applied Physics}, year = {1997}, volume = {82}, number = {9}, pages = {4192-4196}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0039226553&doi=10.1063%2f1.366221&partnerID=40&md5=15d2dd1d12558adde455a33be8b790fa}, doi = {https://doi.org/10.1063/1.366221} } |
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Lesage, C., Oddo, R., Champoux, Y. and Atalla, N. | Experimental characterization of the noise generation mechanism of percussion drill rods | 1997 | CIM Bulletin Vol. 90(1010), pp. 65-69 |
article | URL |
Abstract: An experimental approach is used to characterize the vibroacoustic behaviour of percussion drill steel rods under real operating conditions and laboratory controlled conditions. A laboratory test fixture presenting representative boundary conditions is used. The relative contribution of longitudinal and flexural vibration to the noise generation is discussed. By comparing the laboratory and the in situ measurements, it is shown that the main noise source of percussion drill rods are the flexural waves. However, the noise reduction potential, by reducing the bending vibration, is limited by the radiation of axial waves. | |||||
BibTeX:
@article{Lesage199765, author = {Lesage, C. and Oddo, R. and Champoux, Y. and Atalla, N.}, title = {Experimental characterization of the noise generation mechanism of percussion drill rods}, journal = {CIM Bulletin}, year = {1997}, volume = {90}, number = {1010}, pages = {65-69}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031149645&partnerID=40&md5=babeb1b3a18c969922294f4ca31a9be6} } |
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Masson, P., Berry, A. and Micheau, P. | Wavelets in active structural acoustic control | 1997 | Proceedings - National Conference on Noise Control Engineering Vol. 2, pp. 103-114 |
conference | URL |
Abstract: A new approximation of the radiated acoustic power was proposed using the wavelet transform. This approximation has been applied to a simply-supported beam and it was shown that a single local component of the wavelet transform can represent the vibratory energy in a given region of the structural wave number spectrum. Adjusting the scale parameter of the wavelet allows energy localization over the supersonic region of the structural wave number spectrum, and hence leads to an approximation of the radiated acoustic power. | |||||
BibTeX:
@conference{Masson1997103, author = {Masson, P. and Berry, A. and Micheau, P.}, title = {Wavelets in active structural acoustic control}, journal = {Proceedings - National Conference on Noise Control Engineering}, year = {1997}, volume = {2}, pages = {103-114}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031345251&partnerID=40&md5=18fb814fad1d1dcebe4ac0597c5f0c14} } |
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Masson, P., Berry, A. and Nicolas, J. | Active structural acoustic control using strain sensing | 1997 | Journal of the Acoustical Society of America Vol. 102(3), pp. 1588-1599 |
article | DOI URL |
Abstract: A new strategy based on the direct use of strain sensing is proposed for the minimization of the acoustic radiation from a vibrating plate. This strategy uses active structural acoustic control because it eliminates the need for far-field acoustic sensors. The cost function is defined as the radiated acoustic power and the discrete strain information is given directly, for example, by fiber optic sensors embedded in the structure. Two approaches are presented to express the cost function in terms of strain information. The first one is based on plate's displacement reconstruction from the strain field while the second is based on integration by parts of the wave-number transform of the displacement. Proper concentration of the control effort is obtained with the cost function defined in the wave-number domain. Both approaches are first validated with respect to an analytical solution for the calculation of the radiated acoustic power from structural strain information. It is shown that good agreement is obtained with at least two strain sensors per structural wavelength. Optimal control of acoustic radiation from a simply supported plate is then performed using different configurations of sensors and actuators. The control is performed using simulated piezoelectric actuators and results show that both approaches are well suited for active control applications as they offer good performance over a wide frequency range while requiring only few sensors. | |||||
BibTeX:
@article{Masson19971588, author = {Masson, P. and Berry, A. and Nicolas, J.}, title = {Active structural acoustic control using strain sensing}, journal = {Journal of the Acoustical Society of America}, year = {1997}, volume = {102}, number = {3}, pages = {1588-1599}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030767768&doi=10.1121%2f1.420071&partnerID=40&md5=7d165b8793d3b7c28b5b1afe7f5e591d}, doi = {https://doi.org/10.1121/1.420071} } |
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Nadeau, S., Champoux, Y., Beslin, O. and Chenevert, D. | Vibroacoustic experimental data on a large cavity covered by a flexible panel | 1997 | Proceedings - National Conference on Noise Control Engineering Vol. 1, pp. 451-456 |
conference | URL |
Abstract: This report covers work in progress on the acquisition of reliable experimental data on a large cavity covered by a flexible panel. A summary description of the experimental setup is presented with the description of the plate boundary condition. The quadratic velocity of the plate and the cavity quadratic sound pressure are given for several conditions. Experimental results show that most acoustic cavity modes are removed with the sound absorbing material. | |||||
BibTeX:
@conference{Nadeau1997451, author = {Nadeau, Sylvain and Champoux, Yvan and Beslin, Olivier and Chenevert, Daniel}, title = {Vibroacoustic experimental data on a large cavity covered by a flexible panel}, journal = {Proceedings - National Conference on Noise Control Engineering}, year = {1997}, volume = {1}, pages = {451-456}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031345169&partnerID=40&md5=75b54109bb68828b4a5f2a5128da3d28} } |
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Nélisse, H. and Nicolas, J. | Characterization of a diffuse field in a reverberant room | 1997 | Journal of the Acoustical Society of America Vol. 101(6), pp. 3517-3524 |
article | DOI URL |
Abstract: An efficient modal approach to characterize the diffuseness of the sound field in a rectangular room is presented. Using two simple descriptors, the correlation function and the spatial uniformity of the pressure field, a practical and convenient tool is proposed to study the diffuse field in the room. A precise criterion has been given in terms of the least permissible number of room modes to achieve an adequate diffusion. It has been shown that the criterion is in great accordance with the well-known 'Schroeder frequency' limit for the diffuse field. Detailed calculations of the correlation function are presented to show the importance of the ?k/k correction terms to the well-known sin(kR)/kR prediction. A new closed form for the correlation function is thus derived. A discussion about the importance of having more than one descriptors is also presented. It is shown that a diffuse field can be established in a room with strong modal behavior under certain assumptions. | |||||
BibTeX:
@article{Nélisse19973517, author = {Nélisse, H. and Nicolas, J.}, title = {Characterization of a diffuse field in a reverberant room}, journal = {Journal of the Acoustical Society of America}, year = {1997}, volume = {101}, number = {6}, pages = {3517-3524}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-1842299852&doi=10.1121%2f1.418313&partnerID=40&md5=c9635f01ff1d7b9e7ae2107bf7fc115b}, doi = {https://doi.org/10.1121/1.418313} } |
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Panneton, R. and Atalla, N. | An efficient finite element scheme for solving the three-dimensional poroelasticity problem in accoustics | 1997 | Journal of the Acoustical Society of America Vol. 101(6), pp. 3287-3298 |
article | DOI URL |
Abstract: In this paper, the finite element method (FEM) is used to solve the three-dimensional poroelasticity problem in accoustics based on the isotropic Biot-Allard theory. A displacement finite element model is derived using the Lagrangian approach together with an analogy with solid elements. From this model, it is seen that the 'damping' and 'stiffness' matrices of the poroelastic media are complex and frequency dependent. This leads to cumbersome calculations for large finite element models and spectral analyses. To overcome this difficulty, an efficient algorithm is proposed. It is based on low-frequency approximations of the frequency-dependent dissipation mechanisms in poroelastic media. This efficient algorithm allows the poroelastic materials to be modeled with classical FEM codes. Also, the acoustic-poroelastic and the poroelastic coupling conditions are presented. The proposed model is compared to existing literature for both two- dimensional and three-dimensional problems. Excellent comparisons prove both the accuracy and effectiveness of the proposed model and its coupling with acoustic elements. Finally, to show the usefulness of the proposed model, the edge effect on the absorption coefficient of a multilayered poroelastic material is presented. Results show that analytical models based on laterally infinite poroelastic layers and standing wave tube measurement may be misleading at low frequencies. | |||||
BibTeX:
@article{Panneton19973287, author = {Panneton, R. and Atalla, N.}, title = {An efficient finite element scheme for solving the three-dimensional poroelasticity problem in accoustics}, journal = {Journal of the Acoustical Society of America}, year = {1997}, volume = {101}, number = {6}, pages = {3287-3298}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030983221&doi=10.1121%2f1.418345&partnerID=40&md5=167779f208936b68649b569d7b65cddd}, doi = {https://doi.org/10.1121/1.418345} } |
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Panneton, R. and Atalla, N. | Low-frequency approximations for acoustic porous materials: Linearisation of the poroelastic eigenvalue problem | 1997 | Transactions of the Canadian Society for Mechanical Engineering Vol. 21(4), pp. 401-413 |
article | URL |
Abstract: Recently in acoustics, it was shown that a finite element discretisation of Biot's dynamic equations - for poroelastic media - leads to a non-linear eigenvalue problem. This non-linearity comes from the complex dissipation mechanisms of the elastic and acoustic waves prevailing within the poroelastic material. These complex dissipation mechanisms are related to viscous and thermal effects. The main drawback of the non-linear eigenvalue problem is that it prevents the use of classical modal analysis techniques for efficient solution of the corresponding matrix system. Since the finite element method is mostly used at low-freuqencies, the objective of this paper is to derive low-frequency approximations on the viscous and thermal disssipation mechanisms that will be used to linearise the poroelastic eigenvalue problem. To achieve the linearisation, it will be shown that the first Lamé coefficient of the poroelastic medium can be considered frequency-independent for most acoustic porous materials. | |||||
BibTeX:
@article{Panneton1997401, author = {Panneton, R. and Atalla, N.}, title = {Low-frequency approximations for acoustic porous materials: Linearisation of the poroelastic eigenvalue problem}, journal = {Transactions of the Canadian Society for Mechanical Engineering}, year = {1997}, volume = {21}, number = {4}, pages = {401-413}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031345818&partnerID=40&md5=4ba6f0352b46192a6d58b8a95722a762} } |
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Sgard, F. and Atalla, N. | Mean Flow Effects on a Plate-Backed Cavity. Part 1: Theory | 1997 | Acustica Vol. 83(2), pp. 243-250 |
article | URL |
Abstract: This is part I of a paper dealing with the vibro-acoustic behavior of a baffled plate backed cavity, immersed in a mean flow. The plate is excited by a point force or a plane wave convected by the mean flow. This paper expounds the theory. The formulation is based on a finite element method for both the plate and the cavity. Fluid loading due to mean flow is taken into account through an impedance matrix. This external impedance matrix is calculated using an extended form of the Kirchhoff's integral equation together with a variational boundary element method. To account for the cavity, a system of coupled equations is constructed in terms of structural displacements and acoustic pressure. The solution CPU time is substantially reduced by using a modal expansion in terms of the in vacuo structural modes and rigid cavity modes. Two numerical validation are presented. Part II discusses results regarding the effects of mean flow on the vibro-acoustic indicators of the system. | |||||
BibTeX:
@article{Sgard1997243, author = {Sgard, F. and Atalla, N.}, title = {Mean Flow Effects on a Plate-Backed Cavity. Part 1: Theory}, journal = {Acustica}, year = {1997}, volume = {83}, number = {2}, pages = {243-250}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031094530&partnerID=40&md5=8ea6f36e1e6fea7e0439e4032cc0247f} } |
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Sgard, F. and Atalla, N. | Mean Flow Effects on a Plate-Backed Cavity. Part 2: Results | 1997 | Acustica Vol. 83(2), pp. 251-259 |
article | URL |
Abstract: This is part 2 of a paper dealing with the vibro-acoustic behavior of a baffled plate backed cavity, immersed in a mean flow. The plate is excited by a point force or a plane wave convected by the mean flow. This paper discusses results regarding the effects of mean flow on the vibro-acoustic indicators of the system. | |||||
BibTeX:
@article{Sgard1997251, author = {Sgard, F. and Atalla, N.}, title = {Mean Flow Effects on a Plate-Backed Cavity. Part 2: Results}, journal = {Acustica}, year = {1997}, volume = {83}, number = {2}, pages = {251-259}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0347768999&partnerID=40&md5=65315fc9c5377b29bac8225d38414634} } |
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Wang, W., Atalla, N. and Nicolas, J. | A boundary integral approach for acoustic radiation of axisymmetric bodies with arbitrary boundary conditions valid for all wave numbers | 1997 | Journal of the Acoustical Society of America Vol. 101(3), pp. 1468-1478 |
article | DOI URL |
Abstract: A boundary integral method for solving the exterior acoustic radiation problem of axisymmetric bodies with arbitrary boundary conditions is developed. The new formulation derives from the method proposed by Burton and Miller [Proc. R. Soc. London Ser. A 323, 201-210 (1971)], which uses a linear combination of the Helmholtz integral equation and its normal derivative to ensure the uniqueness of the numerical solution at all frequencies. It is shown that the use of tangential operators enables one to easily compute the hypersingular integral without much extra effort. By taking advantage of the properties of axisymmetric geometry, and using the expansion of the boundary conditions and the surface distribution functions in Fourier series with respect to the angle of revolution, the surface integral is reduced to a line integral along the generator of the body, and Fourier integrals of the Green's function and its derivatives over the circumferential angle. The Fourier integrals with singular kernels are evaluated using recurrence formulas in terms of the complete elliptic integrals. A new approach is then proposed to evaluate the Burton and Miller formulation at a corner by using the left-hand and right-hand limits of normal derivatives. Doing so, isoparametic elements throughout the surface of the body are able to be used. In order to demonstrate the validity and accuracy of the method, numerical results with quadratic isoparametric curvilinear elements are presented for radiation problems of a pulsating sphere, an oscillating sphere, and a finite cylinder with various boundary conditions. | |||||
BibTeX:
@article{Wang19971468, author = {Wang, W. and Atalla, N. and Nicolas, J.}, title = {A boundary integral approach for acoustic radiation of axisymmetric bodies with arbitrary boundary conditions valid for all wave numbers}, journal = {Journal of the Acoustical Society of America}, year = {1997}, volume = {101}, number = {3}, pages = {1468-1478}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031058846&doi=10.1121%2f1.418174&partnerID=40&md5=518bda95e08764e9c0d9c5a1095ca006}, doi = {https://doi.org/10.1121/1.418174} } |
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Wang, W. and Atalla, N. | A numerical algorithm for double surface integrals over quadrilaterals with a 1/R singularity | 1997 | Communications in Numerical Methods in Engineering Vol. 13(11), pp. 885-890 |
article | DOI URL |
Abstract: A new algorithm for the double surface integral with a 1/R singularity over flat or curved quadrilateral elements is presented. This algorithm is of special interest in the numerical implementation of the variational boundary element methods for acoustic radiation of finite-volume bodies. The presented algorithm takes the factor of singularity in an integrand as the weight function, and approximates the integral by the area of the surface element times a weighted average of the remaining integrand at a number of the integral points in the element domain. A numerical example demonstrates the accuracy of the proposed algorithm. © 1997 John Wiley & Sons, Ltd. | |||||
BibTeX:
@article{Wang1997885, author = {Wang, W. and Atalla, N.}, title = {A numerical algorithm for double surface integrals over quadrilaterals with a 1/R singularity}, journal = {Communications in Numerical Methods in Engineering}, year = {1997}, volume = {13}, number = {11}, pages = {885-890}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031276168&doi=10.1002%2f%28SICI%291099-0887%28199711%2913%3a11%3c885%3a%3aAID-CNM112%3e3.0.CO%3b2-D&partnerID=40&md5=f4e8a8be0223016665b251a1fe89e3da}, doi = {https://doi.org/10.1002/(SICI)1099-0887(199711)13:11%3C885::AID-CNM112%3E3.0.CO;2-D} } |
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Atalla, N., Nicolas, J. and Gauthier, C. | Acoustic radiation of an unbaffled vibrating plate with general elastic boundary conditions | 1996 | Journal of the Acoustical Society of America Vol. 99(3), pp. 1484-1494 |
article | DOI URL |
Abstract: If the simulations of the radiated field of a baffled plane structure has been deeply studied, the unbaffled case, although more realistic, has retained little attention. The proposed work investigates the radiation, in light fluid, of a plane unbaffled thin structure of finite dimensions and general elastic boundary conditions. The approach used is based on a variational formulation for the plate's displacement and the pressure jump through the structure. A Rayleigh-Ritz approximation with a polynomial set of trial functions is used for both variables. A good agreement is found with a numerical approach based on a boundary element method. Acoustic radiation of unbaffled rectangular plates will be discussed and compared to the baffled case. This will show in particular that the effect of the baffle is very important at low frequencies but there are no simple tendencies. Precise measurements confirm the validity of the simulations. | |||||
BibTeX:
@article{Atalla19961484, author = {Atalla, N. and Nicolas, J. and Gauthier, C.}, title = {Acoustic radiation of an unbaffled vibrating plate with general elastic boundary conditions}, journal = {Journal of the Acoustical Society of America}, year = {1996}, volume = {99}, number = {3}, pages = {1484-1494}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029965373&doi=10.1121%2f1.414727&partnerID=40&md5=a50f139ea8cccf3de05124b20b1ec359}, doi = {https://doi.org/10.1121/1.414727} } |
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Atalla, N. and Panneton, R. | The effects of multilayer sound-absorbing treatments on the noise field inside a plate backed cavity | 1996 | Noise Control Engineering Journal Vol. 44(5), pp. 235-243 |
article | DOI URL |
Abstract: In this paper, a finite element approach is used to investigate the noise field inside a rigid-walled cavity coupled to a vibrating plate with a multilayer sound-absorbing treatment. The treatment is made from a combination of elastic, poroelastic, and airspace layers. The approach uses classical elastic and fluid elements to model the elastic and fluid media. For poroelastic media, it uses a two-field displacement formulation derived from the Biot theory. Furthermore, it accounts for coupling between elastic, poroelastic, and airspace layers. Numerical results illustrating several practical configurations are presented. They underline several features: the effects of the modal behavior of the structure, the nature of the poroelastic material, the effects of the damping added by the poroelastic material, the mounting configuration of the sound absorbing treatment, and finally the boundary conditions of the plate. © 1996 Institute of Noise Control Engineering. | |||||
BibTeX:
@article{Atalla1996235, author = {Atalla, N. and Panneton, R.}, title = {The effects of multilayer sound-absorbing treatments on the noise field inside a plate backed cavity}, journal = {Noise Control Engineering Journal}, year = {1996}, volume = {44}, number = {5}, pages = {235-243}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030230205&doi=10.3397%2f1.2828408&partnerID=40&md5=0f02bb351011a7557aecd1e519a91847}, doi = {https://doi.org/10.3397/1.2828408} } |
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Berry, A. and Locqueteau, C. | Vibration and sound radiation of fluid-loaded stiffened plates with consideration of in-plane deformation | 1996 | Journal of the Acoustical Society of America Vol. 100(1), pp. 312-319 |
article | DOI URL |
Abstract: A Ritz method is presented for computing the vibration and sound radiation of baffled rectangular plates reinforced by eccentric stiffeners. The model incorporates both bending, transverse shear and in-plane deformation of the plate, and bending, torsional, and extensional deformation of the stiffeners. The in-plane deformation of the plate, resulting from the eccentric stiffener deformations, has not been considered in previous studies. Relevant expressions of the kinetic and strain energies of the mechanical system are detailed. Numerical results of the in-vacuo natural frequencies for various configurations of place thickness, stiffeners, and boundary conditions show the importance of in-plane displacements of the plate, especially when thick plates are involved. The comparisons in terms of in-vacuo natural frequencies between the present approach and available published results as well as FEM calculations show a good agreement. An example of structural response and sound radiation in water is also presented. | |||||
BibTeX:
@article{Berry1996312, author = {Berry, A. and Locqueteau, C.}, title = {Vibration and sound radiation of fluid-loaded stiffened plates with consideration of in-plane deformation}, journal = {Journal of the Acoustical Society of America}, year = {1996}, volume = {100}, number = {1}, pages = {312-319}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030058980&doi=10.1121%2f1.415880&partnerID=40&md5=99bbd5343f2b72c872638496c38d93a2}, doi = {https://doi.org/10.1121/1.415880} } |
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Beslin, O. and Nicolas, J. | Modal radiation from an unbaffled rotating disk | 1996 | Journal of the Acoustical Society of America Vol. 100(5), pp. 3192-3202 |
article | DOI URL |
Abstract: This paper deals with the acoustic radiation from an unbaffled rotating disk. It is shown that when the disk is rotating, the natural modes are no longer stationary modes but are transformed into rotating waves. Using the concept of rotating waves instead of the retarded time potential method, rotation effects are taken into account in the vibratory part of the problem. Thus no assumption has to be made on the rotation speed and the near pressure field can be evaluated. A new collocation method is proposed to solve the double-layer potential problem which does not require evaluating double- surface integration as when using classical methods. A new analytical formula is established to evaluate the Hadamard finite part of the auto-influent terms. Radiation efficiencies of unbaffled rotating waves are calculated and charts are given which are useful for designing quiet circular disks such as saw blades or rotating wheels. Rotating waves are classified as radiating and nonradiating. The disk is not assumed to be baffled as it is the classical case; therefore, the charts given in this study can be used directly for real cases. | |||||
BibTeX:
@article{Beslin19963192, author = {Beslin, O. and Nicolas, J.}, title = {Modal radiation from an unbaffled rotating disk}, journal = {Journal of the Acoustical Society of America}, year = {1996}, volume = {100}, number = {5}, pages = {3192-3202}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029992545&doi=10.1121%2f1.417203&partnerID=40&md5=2bbfa659c52a292aa8fbc60ef149b1d3}, doi = {https://doi.org/10.1121/1.417203} } |
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Champoux, Y., Brunet, S. and Berry, A. | On the construction of a simply supported rectangular plate for noise and vibration studies [BibTeX] |
1996 | Experimental Techniques Vol. 20(1), pp. 24-26 |
article | DOI URL |
BibTeX:
@article{Champoux199624, author = {Champoux, Y. and Brunet, S. and Berry, A.}, title = {On the construction of a simply supported rectangular plate for noise and vibration studies}, journal = {Experimental Techniques}, year = {1996}, volume = {20}, number = {1}, pages = {24-26}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029776622&doi=10.1111%2fj.1747-1567.1996.tb00435.x&partnerID=40&md5=c5645bbbe3e46e7f292dcf5680f0cb44}, doi = {https://doi.org/10.1111/j.1747-1567.1996.tb00435.x} } |
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Guigou, C., Berry, A., Charette, F. and Nicolas, J. | Active control of finite beam volume velocity using shaped PVDF sensor | 1996 | Acustica Vol. 82(5), pp. 772-783 |
article | URL |
Abstract: The radiated sound power of a planar structure is related to the structural volume velocity in the low frequency region. The volume veloctiy associated with a vibration structure is also related to the far-field pressure in the direction orthogonal to that structure. Thus, the minimization of the volume velocity appears as a good strategy for active control of sound radiation. This paper investigates the design of a volume velocity sensor and its integration into an active noise control system in the case of a flexural beam (ID structure). Based on a modal approach, the shape of a PVDF sensor is analytically determined in such a way that the output signal of the sensor is directly proportional to the volume velocity of a harmonically excited finite beam with arbitrary boundary conditions. A general expression of the PVDF sensor shape is obtained and is shown to depend only on the beam and sensor characteristics (material characteristics and boundary conditions). The shape of the sensor is independent of the type and position of the excitation and the control actuator considered. For simply supported or clamped boundary conditions, this type of shaped PVDF sensor detects only contributions from the odd (symmetric) modes, which are the only ones with non-zero volume velocity and also the most effective radiators. For a cantilever beam, this sensor will detect all the modes since none of them has zero volume velocity. A piezoceramic actuator is used to minimize the output signal of the shaped PVDF sensor. The efficiency of this control strategy is demonstrated analytically for a simply-supported and cantilever beam. The far-field radiated acoustic power, the quadratic velocity as well as the radiation efficiency are extensively studied. The results show that such PVDF shaped sensor is very effective in controlling the sound radiation. Experimental implementation of such a PVDF volume velocity sensor as well as the active control using a feedforward harmonic adaptive LMS algorithm are presented and discussed. © S. Hirzel Verlag · EAA. | |||||
BibTeX:
@article{Guigou1996772, author = {Guigou, C. and Berry, A. and Charette, F. and Nicolas, J.}, title = {Active control of finite beam volume velocity using shaped PVDF sensor}, journal = {Acustica}, year = {1996}, volume = {82}, number = {5}, pages = {772-783}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030232273&partnerID=40&md5=7387b82b8b587c773aa3a8e7f7c65209} } |
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Micheau, P., Coirault, P., Hardouin, L. and Tartarin, J. | Adaptive rejection of the preponderant harmonic of a pulsed flow | 1996 | IEEE Transactions on Control Systems Technology Vol. 4(4), pp. 452-458 |
article | DOI URL |
Abstract: Pulsed flows, characterized by periodic fluctuations in flow rate, are noise-productive, but an oscillating valve positioned in the exhaust duct can attenuate the main harmonic of pulsed flow. We define a valve adaptive control in the frequency domain implemented by a digital signal processor for experimental purposes. Results show noise reduction at ground level and tracking of process unstationarity. © 1996 IEEE. | |||||
BibTeX:
@article{Micheau1996452, author = {Micheau, P. and Coirault, P. and Hardouin, L. and Tartarin, J.}, title = {Adaptive rejection of the preponderant harmonic of a pulsed flow}, journal = {IEEE Transactions on Control Systems Technology}, year = {1996}, volume = {4}, number = {4}, pages = {452-458}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030194060&doi=10.1109%2f87.508894&partnerID=40&md5=2fda4c9adcd63c6109bcef60e27787c7}, doi = {https://doi.org/10.1109/87.508894} } |
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Nelisse, H., Beslin, O. and Nicolas, J. | Fluid-structure coupling for an unbaffled elastic panel immersed in a diffuse field | 1996 | Journal of Sound and Vibration Vol. 198(4), pp. 485-506 |
article | DOI URL |
Abstract: The study of the structural response of a panel excited by a multiple plane-wave acoustic field is presented. A new semi-analytical approach based on the integral equation method is proposed. The two major difficulties lie in the fact that the panel is unbaffled and is excited by an acoustic field, a system for which the fluid-structure coupling cannot be neglected a priori. Using the free-space Green function and a variational approach, a linear system is obtained for the two unknowns of the problem, the sound pressure jump and the panel deflection. The formulation allows one to obtain a simple physical interpretation in terms of the diffraction and radiation phenomenon. An efficient computation scheme is introduced for the admittance matrix as well as a multiexcitation procedure for the acoustic plane-waves. Convergence of the method is discussed and a comparison with a modal-cavity approach is presented. Finally, the importance of the diffraction by the panel is discussed with regards to approximations usually performed in some numerical techniques. © 1996 Academic Press Limited. | |||||
BibTeX:
@article{Nelisse1996485, author = {Nelisse, H. and Beslin, O. and Nicolas, J.}, title = {Fluid-structure coupling for an unbaffled elastic panel immersed in a diffuse field}, journal = {Journal of Sound and Vibration}, year = {1996}, volume = {198}, number = {4}, pages = {485-506}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030396085&doi=10.1006%2fjsvi.1996.0583&partnerID=40&md5=22c05d6952500731e03565e151aea86d}, doi = {https://doi.org/10.1006/jsvi.1996.0583} } |
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Panneton, R. and Atalla, N. | Numerical prediction of sound transmission through finite multilayer systems with poroelastic materials | 1996 | Journal of the Acoustical Society of America Vol. 100(1), pp. 346-354 |
article | DOI URL |
Abstract: The sound transmission performance of finite multilayer systems containing poroelastic materials is of utmost importance for noise control in automobiles, aircrafts, buildings, and several other engineering applications. Currently, the need for tools predicting the acoustical and structural behaviors of such structures is considerably increasing. In this paper, such a tool is presented. It is applied to the sound transmission loss through multilayer structures made from a combination of elastic, air, and poroelastic materials. The presented approach is based on a three-dimensional finite clement model. It uses classical elastic and fluid elements to model the elastic and fluid media. For the poroelastic material, it uses a two- field displacement formulation derived from the Biot theory. Furthermore, it couples with a boundary element approach to account, when important, for fluid-structure coupling and to calculate the transmission loss through the multilayer structure. Numerical predictions of the transmission loss through a poroelastic material sandwiched between two finite elastic plates are presented for various configurations. It is shown that the unbonded/bonded configuration gives better transmission loss. Also, comparisons with laterally infinite double panels and with an equivalent fluid approach for the porous material are presented. It is shown that these two simplified models lead to erroneous predictions at low frequencies and for certain design configurations, respectively. | |||||
BibTeX:
@article{Panneton1996346, author = {Panneton, R. and Atalla, N.}, title = {Numerical prediction of sound transmission through finite multilayer systems with poroelastic materials}, journal = {Journal of the Acoustical Society of America}, year = {1996}, volume = {100}, number = {1}, pages = {346-354}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030062210&doi=10.1121%2f1.415956&partnerID=40&md5=0b184345d80c0162689350abc51d67ed}, doi = {https://doi.org/10.1121/1.415956} } |
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Amédin, C., Berry, A., Champoux, Y. and Allard, J.-F. | Sound field of a baffled piston source covered by a porous medium layer | 1995 | Journal of the Acoustical Society of America Vol. 98(3), pp. 1757-1766 |
article | DOI URL |
Abstract: Two models for the prediction of sound transmission through a thick layer of material which lies on a horizontal baffle are presented. These models are a preliminary investigation of a method for the acoustical and physical characterizations of porous màterials. The acoustic source is assumed to be a circular, baffled piston source mounted under a layer of porous material. The sound is transmitted through the porous layer to the semi-infinite half-space above the layer. The models are used to calculate the transfer function between the volume velocity of the source and the sound pressure above the porous material. The first model is based on the integral method in which appropriate Green's functions are used to describe the sound field, and on a collocation procedure. The second model uses a method of decomposition of the sound field into cylindrical waves. The numerical results of the two models are in good agreement. A significant sensitivity of the transmitted sound field to the material's physical characteristics is observed. The models’ predictions are in good agreement with those from the literature on the limiting case of a circular piston radiating in a semi-infinite medium. The cylindrical wave decomposition method is found to be much faster in terms of computation time, and more general than the integral method model. © 1995, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Amédin19951757, author = {Amédin, C.K. and Berry, A. and Champoux, Y. and Allard, J.-F.}, title = {Sound field of a baffled piston source covered by a porous medium layer}, journal = {Journal of the Acoustical Society of America}, year = {1995}, volume = {98}, number = {3}, pages = {1757-1766}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029131134&doi=10.1121%2f1.413440&partnerID=40&md5=ccfcc0943db1ce6bed2ea9d5a0461ef2}, doi = {https://doi.org/10.1121/1.413440} } |
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Atalla, N., Cote, A., Cournoyer, B. and Nicolas, J. | Vibroacoustic behavior of a rotating annular complex plate with application to the design of circular saws | 1995 | American Society of Mechanical Engineers, Design Engineering Division (Publication) DE Vol. 84(3 Pt B/1) |
conference | URL |
Abstract: This paper discusses the vibroacoustic behavior of an annular rotating complex plate with application to the design of circular saws. The effects of rotation and constrained viscoelastic damping are investigated both theoretically and experimentally. On the theoretical front, a model based on the variational approach has been developed. Special attention has been devoted to 1) the effects of rotation on both the vibration and the noise radiated by the annular plate and 2) the optimization of viscoelastic constrained damping. On the experimental front, several set ups have been devised to validate the theoretical models and to test some noise reduction avenues. Examples showing predictions from the theoretical models will be presented together with comparisons to experimental data. Finally, application of the above results to the design of a quieter circular saw will be discussed. | |||||
BibTeX:
@conference{Atalla1995, author = {Atalla, Noureddine and Cote, Andre and Cournoyer, Benoit and Nicolas, Jean}, title = {Vibroacoustic behavior of a rotating annular complex plate with application to the design of circular saws}, journal = {American Society of Mechanical Engineers, Design Engineering Division (Publication) DE}, year = {1995}, volume = {84}, number = {3 Pt B/1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029429784&partnerID=40&md5=8425c66895fa5b37fca5b5daa409034a} } |
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Atalla, N. and Nicolas, J. | A formulation for mean flow effects on sound radiation from rectangular baffled plates with arbitrary boundary conditions | 1995 | Journal of Vibration and Acoustics, Transactions of the ASME Vol. 117(1), pp. 22-29 |
article | DOI URL |
Abstract: A general formulation of the sound radiation from fluid-loaded rectangular baffled plates with arbitrary boundary conditions has been developed by Berry et al. (JASA, Vol. 90, No. 4, Pt. 2, 1991). In this paper, an extension of this formulation to inviscid, uniform subsonic flow is considered. The analysis is based on a variational formulation for the transverse vibrations of the plate and the use of the extended, to uniformly moving media, form of the Helmholtz integral equation. The formulation shows explicitly the effect of the flow in terms of added mass, and radiation resistance. Furthermore, it avoids the difficult problem of integration in the complex domain, typical of the wavenumber transform approaches to fluid-loading problems. Comparison of the acoustic radiation impedance with existing studies supports the validity of the approach. The details of the formulation and its numerical implementation is exposed and a discussion of the flow effects on the radiation impedance of a rectangular piston is presented. It is shown that subsonic mean flow increases the modal radiation resistance at low frequencies and affects added mass more strongly than it affects radiation resistance. © 1995 by ASME. | |||||
BibTeX:
@article{Atalla199522, author = {Atalla, N. and Nicolas, J.}, title = {A formulation for mean flow effects on sound radiation from rectangular baffled plates with arbitrary boundary conditions}, journal = {Journal of Vibration and Acoustics, Transactions of the ASME}, year = {1995}, volume = {117}, number = {1}, pages = {22-29}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029230729&doi=10.1115%2f1.2873863&partnerID=40&md5=ff2c8964f5ab82f4dcf88314009677a4}, doi = {https://doi.org/10.1115/1.2873863} } |
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Berry, A., Oddo, R., Panneton, R. and Nicolas, J. | Reducing the noise of pressure pulp screen: theory and application | 1995 | American Society of Mechanical Engineers, Design Engineering Division (Publication) DE Vol. 84(3 Pt B/1) |
conference | URL |
Abstract: A pressure pulp screen is a machine used in the pulp and paper industry to remove and class cellulose fibres in paper pulp. It involves an inner perforated cylindrical basket which receives the pulp under pressure, an inner rotor with profiled blades used to clear the holes or slits of the basket, and an outer cylindrical shell. The noise radiated by the outer shell is characterized by discrete frequencies in mid- and high frequency (1-4 kHz). A preliminary study has shown that the radiated noise is due to the vibration of the perforated basket under the moving load of the rotor. This vibration is transmitted to the outer shell through various paths which were analyzed and classified. An analytical model of the vibroacoustic behavior of a cylindrical shell under a circumferentially moving load was used to establish various rotating speed regimes with respect to the vibration and sound radiation of the shell. It was shown that a circumferential modulation of the load (corresponding to the effect of holes or slits on the inner basket) leads to theoretical noise spectra similar to measured data. On the practical front, the model was used to identify significant design parameters with respect to the noise of the machine. The paths of energy transmission from the basket to the outer shell were studied and various noise reduction approaches have been investigated. | |||||
BibTeX:
@conference{Berry1995, author = {Berry, Alain and Oddo, Remy and Panneton, Raymond and Nicolas, Jean}, title = {Reducing the noise of pressure pulp screen: theory and application}, journal = {American Society of Mechanical Engineers, Design Engineering Division (Publication) DE}, year = {1995}, volume = {84}, number = {3 Pt B/1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029429286&partnerID=40&md5=d48e9983fc5d0627996365776e796388} } |
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Berry, A., Charette, F. and Guigou, C. | Volume velocity sensors for plates | 1995 | American Society of Mechanical Engineers (Paper), pp. 8pp | conference | URL |
Abstract: The net structural volume velocity of a flexural panel is simply related to the farfield sound pressure radiated normally to the panel, as well as the low frequency radiated sound power. A single, distributed error sensor measuring the structural volume velocity of a panel would thus alleviate the need of multiple error microphones in the active control of structural radiation. The design and implementation of such a volume velocity sensor using shaped PVDF films is discussed for panels with arbitrary boundary conditions. The sensor obtained is independent of the type and frequency of excitation. Procedures for deriving the sensor geometry from an experimental modal analysis of the structure are presented. Analytical simulations of the active control of volume velocity are discussed; the results show that the control mechanism may combine both modal reduction and modal restructuring. The experimental implementation of the volume velocity sensor is addressed, and results of active control using piezoceramic (PZT) actuators are presented. | |||||
BibTeX:
@conference{Berry1995, author = {Berry, Alain and Charette, Francois and Guigou, Catherine}, title = {Volume velocity sensors for plates}, journal = {American Society of Mechanical Engineers (Paper)}, year = {1995}, pages = {8pp}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-17644430243&partnerID=40&md5=cd1faafbe187d4217d3ced9e84490403} } |
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Charron, F., Panneton, R., Champoux, Y., Guerin, J.-M. and Boily, S. | Analytical, numerical and experimental study of the vibro-acoustic behaviour of a stiffened shell structure | 1995 | American Society of Mechanical Engineers, Design Engineering Division (Publication) DE Vol. 84(3 Pt B/1) |
conference | URL |
Abstract: The main objectives of this study are a better understanding of the vibro-acoustic behaviour of an airplane fuselage type structure including stiffeners and a better comprehension of the measuring techniques and the modelization approaches for this type of problem. In order to meet the above objectives, three different models were developed. The first one is an experimental model where the measured accelerations and acoustic pressures are used as a reference for the validation of predicted results. The second model is based on a semi-analytical approach. This model is derived from variational and integral approaches and solved approximately using a Rayleigh-Ritz method. Finally, the last model is based on the finite element method. Several iterations have been necessary before reaching an excellent agreement between all three approaches, especially regarding acoustic responses. From the initial correlation between the measured and predicted results, two major problems were identified. The first one is related to convergence problem associated with the semi-analytical model when stiffeners are incorporated in the model. The second problem is associated with the proper definition of the fluid-structure intermodal coupling in the numerical and analytical approaches. This paper will present the various approaches and models. Furthermore, the investigation on the previous problems will be discussed in detail. In conclusion, new modelization limitations were identified and new modelization criteria for the intermodal coupling were developed from the present study. These results will be used for an in-depth study on the vibro-acoustic behaviour of 1/3 scale model of airplane fuselage. | |||||
BibTeX:
@conference{Charron1995, author = {Charron, Francois and Panneton, Raymond and Champoux, Yvan and Guerin, J.-M. and Boily, Sylvain}, title = {Analytical, numerical and experimental study of the vibro-acoustic behaviour of a stiffened shell structure}, journal = {American Society of Mechanical Engineers, Design Engineering Division (Publication) DE}, year = {1995}, volume = {84}, number = {3 Pt B/1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029430644&partnerID=40&md5=b636a8e652bfb15d736af16abca011eb} } |
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Labrecque, P., Couture, D. and Champoux, Y. | Experimental investigation of the vibroacoustic behavior of structures for validation purposes | 1995 | Applied Acoustics Vol. 46(2), pp. 197-210 |
article | DOI URL |
Abstract: Various test parameters that might affect the accuracy of the vibrational characteristics of thin plates are examined. For the development and validation of acoustical radiation models based on the vibrational characteristics of the structure, the relative influence of these parameters is evaluated and limits are provided. Vibrational and acoustical experimental results on several free-free plates are presented. The influence of excitation source types, mass loading and mass compensation procedures are examined in view of the inherent variability between test specimens. © 1995. | |||||
BibTeX:
@article{Labrecque1995197, author = {Labrecque, P. and Couture, D. and Champoux, Y.}, title = {Experimental investigation of the vibroacoustic behavior of structures for validation purposes}, journal = {Applied Acoustics}, year = {1995}, volume = {46}, number = {2}, pages = {197-210}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-58149326572&doi=10.1016%2f0003-682X%2895%2900015-2&partnerID=40&md5=7d17c5fb06c82fe450e2afbc9e0d139f}, doi = {https://doi.org/10.1016/0003-682X(95)00015-2} } |
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Micheau, P., Coirault, P., Hardouin, L. and Tartarin, J. | Adaptive rejection of the preponderant harmonic of a pulsed flow | 1995 | IEEE Conference on Control Applications - Proceedings, pp. 1108-1113 | conference | URL |
Abstract: Pulsed flows, characterized by periodic fluctuations in flow rate, are noise-productive, but an oscillating valve positioned in the exhaust duct can attenuate the main harmonic of pulsed fow. We define a valve adaptive control in the frequency domain implemented by a digital signal processor for experimental purposes. Results show noise reduction at ground level and tracking of process unstationarity. | |||||
BibTeX:
@conference{Micheau19951108, author = {Micheau, P. and Coirault, P. and Hardouin, L. and Tartarin, J.}, title = {Adaptive rejection of the preponderant harmonic of a pulsed flow}, journal = {IEEE Conference on Control Applications - Proceedings}, year = {1995}, pages = {1108-1113}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029514837&partnerID=40&md5=3a131554f1ebe4715fbeef81e8e646d3} } |
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Micheau, P., Coirault, P., Renault, S. and Tartarin, J. | Adaptive control in the frequency domain of pulsed flow | 1995 | Proceedings of the American Control Conference Vol. 3, pp. 2064-2068 |
conference | URL |
Abstract: Pulsed flows, characterized by periodic fluctuations in flow rate, are noise-productive, but an oscillating flap positioned in the exhaust duct can attenuate the main harmonic of pulsed flow. The approach developed in this study consists of tackling the problem relative to the amplitude and instantaneous phases of the harmonic of each process signal. This control allows the explicit expression of a feedback corrector with a pole on the harmonic to be attenuated. It has the advantages of the adaptive control defined in the frequency domain: simplified modeling, robustness and saved calculation time thanks to undersampling. The result is an adaptive system control without extra-signal injection or blockage of the estimator. The flap adaptive control defined in the frequency domain is implemented by a digital signal processor for experimental purposes. Results show noise reduction at ground level and the availability of the algorithm to track transients dynamics. | |||||
BibTeX:
@conference{Micheau19952064, author = {Micheau, P. and Coirault, P. and Renault, S. and Tartarin, J.}, title = {Adaptive control in the frequency domain of pulsed flow}, journal = {Proceedings of the American Control Conference}, year = {1995}, volume = {3}, pages = {2064-2068}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029180312&partnerID=40&md5=a66d84adbd0a86396b0e76c803f8516a} } |
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Nelisse, H., Beslin, O. and Nicolas, J. | Panel dynamic response to a reverberant acoustic field | 1995 | AIAA Journal Vol. 33(9), pp. 1590-1596 |
article | DOI URL |
Abstract: A novel semianalytical approach based on the integral equation method has been developed to predict the structural response of a panel located in a rigid-walled cavity. This problem is related to the study of the acoustic response of satellite panels with electronic equipment. The main difficulty lies in the treatment of the response of an unbaffled panel, strongly coupled to a high modal density pressure field. A two-indices empty cavity Green's function is used, inspired from electromagnetism. The plate contribution to the sound pressure is obtained byexpanding the pressure jump and Green's function on the same basis functions. This approach presents two main advantages: it reduces the size of the linear system to be solved and avoids ill-conditioning problems. This method isfound to be quite efficient (10 s per frequency point on a 10 Mflops machine). Results show that the panel responds better at acoustical eigenfrequencies than at its in vacuo modes. The values at which the diffraction phenomena governs the structural and acoustic responses are pointed out in terms of density and flexural rigidity. Finally, the formulation allows the quantification of differences between light and heavy fluid environments. © 1995, American Institute of Aeronautics and Astronautics, Inc., All rights reserved. | |||||
BibTeX:
@article{Nelisse19951590, author = {Nelisse, H. and Beslin, O. and Nicolas, J.}, title = {Panel dynamic response to a reverberant acoustic field}, journal = {AIAA Journal}, year = {1995}, volume = {33}, number = {9}, pages = {1590-1596}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029360833&doi=10.2514%2f3.12697&partnerID=40&md5=42351a2f7db9aded97220f7eb9294df7}, doi = {https://doi.org/10.2514/3.12697} } |
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Nicolas, J., Atalla, N., Foin, O. and Berry, A. | Structural acoustic design | 1995 | American Society of Mechanical Engineers, Design Engineering Division (Publication) DE Vol. 84(3 Pt B/1) |
conference | URL |
Abstract: Today, acoustic quietening of manufactured products is gaining importance. Due to cost, severe weight and operational constraints, classically noise control techniques are becoming less attractive. At present, engineers follow essentially two major approaches: (i) reduce noise by passive means, design modifications of structures and systems (ii) reduce noise by active sound and vibration control. This presentation is devoted to the structural acoustic design approach for which there are either some simple rules of thumb either huge numerical codes. The main objective is to bridge the gap between these two extremes. | |||||
BibTeX:
@conference{Nicolas1995, author = {Nicolas, Jean and Atalla, Noureddine and Foin, Olivier and Berry, Alain}, title = {Structural acoustic design}, journal = {American Society of Mechanical Engineers, Design Engineering Division (Publication) DE}, year = {1995}, volume = {84}, number = {3 Pt B/1}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029428324&partnerID=40&md5=3be269030da3cc684e3ff164a1d98433} } |
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Paillard, B., Donh, C., Berry, A. and Nicolas, J. | Accelerating the convergence of the filtered-X LMS algorithm through transform-domain optimisation | 1995 | Mechanical Systems and Signal Processing Vol. 9(4), pp. 445-464 |
article | DOI URL |
Abstract: This paper presents an investigation into the use of a transform-domain optimisation, to accelerate the convergence of the filtered-x least mean squares (LMS) algorithm. It is illustrated by results from a real-time active noise control system, cancelling the noise propagating in a one-dimensional duct. On this real-time test platform, we compare the convergence behaviour of the transform-domain filtered-x LMS, to the convergence behaviour of the standard filtered-x LMS. It is shown that the near optimal convergence speed of the transform-domain filtered-x LMS algorithm, its structural simplicity, and its low computational complexity make it a good alternative to other fast algorithms such as the recursive least squares algorithm, the fast Kalman algorithm, or other approaches based on lattice filters. © 1995 Academic Press Limited. | |||||
BibTeX:
@article{Paillard1995445, author = {Paillard, B. and Donh, C.T.L. and Berry, A. and Nicolas, J.}, title = {Accelerating the convergence of the filtered-X LMS algorithm through transform-domain optimisation}, journal = {Mechanical Systems and Signal Processing}, year = {1995}, volume = {9}, number = {4}, pages = {445-464}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646119359&doi=10.1006%2fmssp.1995.0035&partnerID=40&md5=e954ec5b447aa58c55042d02218c777c}, doi = {https://doi.org/10.1006/mssp.1995.0035} } |
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Panneton, R., Berry, A. and Laville, F. | Vibration and sound radiation of a cylindrical shell under a circumferentially moving load | 1995 | Journal of the Acoustical Society of America Vol. 98(4), pp. 2165-2173 |
article | DOI URL |
Abstract: A theoretical model is developed to evaluate the vibration and sound radiation of a thin cylindrical shell excited by a constant point load continuously traveling along the circumferential direction at a rotational speed O. This rotating load model takes into account the exterior fluid loading due to the sound pressure radiated by the shell. The three equations of the vibroacoustic problem are the shell equations of motion, the Helmholtz equation in the exterior fluid medium and the continuity equation at fluid-shell interface. The rotating load model is based on a frequency-domain solution which is convenient for the interpretation of the vibratory and acoustic responses in terms of shell modes. The equations of motion are expanded over the shell modes to give the modal equations of motion. A frequency-domain representation of the rotating load shows that its frequency content is a series of equal amplitude harmonics N. Each harmonic excites exclusively the circumferential mode N. For this rotating excitation, vibration and radiation critical speeds are identified. They give, respectively, an indication at which rotational speeds high vibration levels and sound radiation efficiency are expected. Finally, a good coirelation between the rotating load model and experiments are obtained. © 1995, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Panneton19952165, author = {Panneton, R. and Berry, A. and Laville, F.}, title = {Vibration and sound radiation of a cylindrical shell under a circumferentially moving load}, journal = {Journal of the Acoustical Society of America}, year = {1995}, volume = {98}, number = {4}, pages = {2165-2173}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029101294&doi=10.1121%2f1.413331&partnerID=40&md5=d392fe8bc8508f8247b7723cd8327f3b}, doi = {https://doi.org/10.1121/1.413331} } |
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Woodcock, R. and Nicolas, J. | A generalized model for predicting the sound transmission properties of generally orthotropic plates with arbitrary boundary conditions | 1995 | Journal of the Acoustical Society of America Vol. 97(2), pp. 1099-1112 |
article | DOI URL |
Abstract: Sound transmission is of significant concern in practical situations, such as building noise insulation or quietening of mechanical products. If the medium- and high-frequency response are well mastered, it is not the case in the low-frequency range where some discrepancies between experiments and theory remain sometimes unexplained. In view of these limitations, the scope of this work is to develop a generalized model which focuses on aspects particularly important in the low-frequency range, namely (1) the finite size of the panel, (2) the orthotropy properties, and (3) the boundary conditions. A variational approach is adopted. The Hamilton functional is built starting with the general tensor relationships between stresses and strains for a generally orthotropic plate. The extremalization is performed using the Rayleigh-Ritz method in conjunction with a nonorthogonal polynomial basis in order to deal with general boundary conditions. The excitation is an acoustic plane wave of any incidence and the radiated field is calculated with an impedance matrix including the cross coupling terms. The different vibroacoustic indicators are the quadratic velocity of the plate, its radiation efficiency, and the transmission loss. The importance of including the intermodal interaction is clearly pointed out. It produces narrow peaks of transmission loss well above the classical mass law. The effect of the dimensions of the panels is shown rigorously and suggests that experimental results should be given in narrow-band if one wants to get usable data. The model also allows, probably for the first time, the effect of the boundary conditions to be fully analyzed. Interestingly enough, the free-free case gives a much bigger transmission loss in the low-frequency range which gives an insight, when possible, for improving the transmission loss. © 1995, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Woodcock19951099, author = {Woodcock, R. and Nicolas, J.}, title = {A generalized model for predicting the sound transmission properties of generally orthotropic plates with arbitrary boundary conditions}, journal = {Journal of the Acoustical Society of America}, year = {1995}, volume = {97}, number = {2}, pages = {1099-1112}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028852786&doi=10.1121%2f1.412222&partnerID=40&md5=ab2431889c7c343c571366f0382a2316}, doi = {https://doi.org/10.1121/1.412222} } |
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Atalla, N. and Berry, A. | Acoustic radiation from a coupled planar semi-complex structure in heavy fluid | 1994 | Journal of Ship Research Vol. 38(3), pp. 213-224 |
article | URL |
Abstract: A mathematical model is derived to address the vibrations and sound radiation into a dense fluid, of a coupled system consisting of two semi-complex plates (i.e., supporting added mass, stiffeners, and having arbitrary elastic boundary conditions) linked in four points through multistage suspensions elements. The supporting plate is subjected to point, line or surface harmonic excitation, while the radiating plate is excited through the suspensions. Both plates are assumed to be baffled, and the radiating plate is fluid loaded. The model is based on a variational approach for the plates, and a matrix transfer approach is used to handle the coupling between the two-plates. The solution is found using a Rayleigh-Ritz expansion in terms of polynomial trial functions which are shown to allow for the arbitrary elastic boundary conditions and to facilitate the calculation of the radiation impedance matrix. The vibrations and noise design of the system is discussed. The main design indicators are the force transmissibilities between the different excitation and attachment points, the mean square velocity, the radiated power and the radiation efficiency of the radiating plate. Numerical examples are presented to show the effects of fluid loading and different design parameters (plates thickness, boundary conditions, added mass, stiffeners, etc.) on the radiated sound. | |||||
BibTeX:
@article{Atalla1994213, author = {Atalla, Noureddine and Berry, Alain}, title = {Acoustic radiation from a coupled planar semi-complex structure in heavy fluid}, journal = {Journal of Ship Research}, year = {1994}, volume = {38}, number = {3}, pages = {213-224}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028515794&partnerID=40&md5=d06e1a8381438a225b7589ab4e09a252} } |
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Atalla, N. and Bernhard, R. | Review of numerical solutions for low-frequency structural-acoustic problems | 1994 | Applied Acoustics Vol. 43(3), pp. 271-294 |
article | DOI URL |
Abstract: Numerical methods for predicting the behavior of structural acoustic systems are becoming increasingly practical. In this paper, the theoretical basis of the most popular state-of-the-art numerical structural-acoustic analysis techniques, the finite element methods and boundary element methods, are described in general terms. Typical approximations are described to identify both the best utilization and the limitations of the methods. Models for cases of heavy and light fluid loading are discussed. The methods are compared to each other and to analytical methods. A comprehensive literature review is included for identification of more complete references describing the methods. © 1994. | |||||
BibTeX:
@article{Atalla1994271, author = {Atalla, N. and Bernhard, R.J.}, title = {Review of numerical solutions for low-frequency structural-acoustic problems}, journal = {Applied Acoustics}, year = {1994}, volume = {43}, number = {3}, pages = {271-294}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028555210&doi=10.1016%2f0003-682X%2894%2990050-7&partnerID=40&md5=01f163c2503790d224dd54a7ca97d075}, doi = {https://doi.org/10.1016/0003-682X(94)90050-7} } |
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Atalla, N. and Nicolas, J. | A new tool for predicting rapidly and rigorously the radiation efficiency of plate-like structures | 1994 | Journal of the Acoustical Society of America Vol. 95(6), pp. 3369-3378 |
article | DOI URL |
Abstract: The objectives of this paper are twofold. Firstly, to present a comparison of several models used to evaluate the radiation efficiency of plate-like radiators. the models compared ranged from very simple ones based on modal average expressions, to refined calculations of the radiation impedance matrix with cross modal coupling. it will be seen in particular that simple models, such as Ver and Holmer's model, give useful guidelines especially for broadband excitations, spatially distributed forces, and thick plates. Expensive methods, such as the far-field approach and BEM are normally used when the hypothesis made in simple models are violated (such as with thin plates and situations where cross modal coupling is important). Secondly, to present a new alternative approach allowing a quick and rigorous evaluation of the radiation efficiency of plate like radiators. This new approach, based on a Taylor's expansion of the Green's function, has several advantages over the classical approaches which will be discussed in the paper. This approach represents a step towards answering the accuracy versus computation time problematic currently brought up by some engineers. © 1994, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Atalla19943369, author = {Atalla, N. and Nicolas, J.}, title = {A new tool for predicting rapidly and rigorously the radiation efficiency of plate-like structures}, journal = {Journal of the Acoustical Society of America}, year = {1994}, volume = {95}, number = {6}, pages = {3369-3378}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028362556&doi=10.1121%2f1.409956&partnerID=40&md5=90a743a2b2b0b8cb95409fb40defea5c}, doi = {https://doi.org/10.1121/1.409956} } |
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Atalla, N. and Glegg, S. | A geometrical acoustics approach for calculating the effects of flow on acoustics scattering | 1994 | Journal of Sound and Vibration Vol. 171(5), pp. 681-694 |
article | DOI URL |
Abstract: A ray acoustics approach to flow effects on acoustics scattering is considered, based on a combination of geometrical acoustics and the paraxial ray approximation. The approach allows for scattering by objects of arbitrary shapes, inhomogeneous and moving media. Applications to flow effects on scattering include the effect of a wall shear layer on scattering from a cylindrical shaped fuselage and the effects of an incompressible inviscid flow on the directivity pattern of the scattered field from a cylinder and a Rankine body. It has been found that the flow causes a modification and displacement of the lobes of the directivity pattern and the shadow zone of the scattered field, which can be important at Mach numbers greater than 0·2. © 1994 Academic Press Limited. | |||||
BibTeX:
@article{Atalla1994681, author = {Atalla, N. and Glegg, S.}, title = {A geometrical acoustics approach for calculating the effects of flow on acoustics scattering}, journal = {Journal of Sound and Vibration}, year = {1994}, volume = {171}, number = {5}, pages = {681-694}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028416721&doi=10.1006%2fjsvi.1994.1149&partnerID=40&md5=10f742b3c8317eaa930ed0f70d9a7e70}, doi = {https://doi.org/10.1006/jsvi.1994.1149} } |
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Berry, A. and Nicolas, J. | Structural acoustics and vibration behavior of complex panels | 1994 | Applied Acoustics Vol. 43(3), pp. 185-215 |
article | DOI URL |
Abstract: Among the many mechanical parameters that influence structure-borne sound are the effects of stiffeners, added mass and complex support conditions along the structure boundaries. In the present paper, these effects are incorporated into a model of sound radiation in air from a complex, baffled, rectangular panel under harmonic point force or point moment excitation. A complex panel is thus defined as a panel which is stiffened lengthwise and widthwise by flexural-torsional beams, which carries point masses and which is elastically restrained against transverse displacement and rotation along the edges. The vibration of the panel assumes no fluid loading and is solved using the Rayleigh-Ritz method with simple polynomial trial functions. The expressions of the kinetic and strain energies associated with stiffeners, added mass and elastic boundary conditions, are detailed. A simple computation scheme is used to derive the farfield sound pressure from the transverse displacement of the panel. Numerical results are shown in terms of the mean quadratic velocity of the panel, radiated sound power and radiation efficiency for a variety of situations including force or moment excitation, simply-supported, clamped or free edges, addition of stiffeners and addition of a point mass, and are used to draw some useful guidelines in practice. © 1994. | |||||
BibTeX:
@article{Berry1994185, author = {Berry, A. and Nicolas, J.}, title = {Structural acoustics and vibration behavior of complex panels}, journal = {Applied Acoustics}, year = {1994}, volume = {43}, number = {3}, pages = {185-215}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028574638&doi=10.1016%2f0003-682X%2894%2990047-7&partnerID=40&md5=07d421c415c78ce9b6f2e60c01099c7a}, doi = {https://doi.org/10.1016/0003-682X(94)90047-7} } |
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Berry, A., Guigou, C. and Charette, F. | Active control of noise by minimizing the volume flow rate of structures. analysis and experience [Controle actif du bruit par minimisation du debit volumique de structures: analyse et experiences] | 1994 | Journal De Physique Vol. 4(5 pt 1), pp. 203-206 |
article | URL |
Abstract: The active control of structurally radiated sound requires in general a large number of error sensors on the vibrating structure. A simple control strategy, using only one error signal - the volume velocity of the structure - has recently been proposed. Such a strategy allows (i) to control all the structural modes that are monopole radiators at low frequencies (i.e., with a high radiation efficiency), (ii) to keep the control set-up simple (only one information is to be minimized). The volume velocity is measured using piezoelectric PVDF strip. The shape of the PVDF strip is determined in such a way that the output signal from the PVDF sensor is directly proportional to the volume velocity induced by the structure on which it is bonded. Using a modal approach, the sensor shape is shown to depend only on the structure and sensor characteristics. However, it is independent of the excitation and the frequency. For a simply supported beam, the shape of such a PVDF sensor is shown and experimental validations are presented for the measure of the volume velocity. Active control was then implemented with this PVDF error sensor and piezoceramic actuators for different frequencies of excitation, using a one-channel feedforward adaptive LMS algorithm. Results show that sound radiation can be efficiently attenuated using this strategy when the system is driven 'on-resonance'. However, when the system is driven 'off-resonance', the axial effects induced by the asymmetric piezoceramic actuators limit the control efficiency. | |||||
BibTeX:
@article{Berry1994203, author = {Berry, A. and Guigou, C. and Charette, F.}, title = {Active control of noise by minimizing the volume flow rate of structures. analysis and experience [Controle actif du bruit par minimisation du debit volumique de structures: analyse et experiences]}, journal = {Journal De Physique}, year = {1994}, volume = {4}, number = {5 pt 1}, pages = {203-206}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028425054&partnerID=40&md5=d6878cbb8b6388c425eb8614671eb9a0} } |
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Berry, A. | A new formulation for the vibrations and sound radiation of fluid-loaded plates with elastic boundary conditions | 1994 | Journal of the Acoustical Society of America Vol. 96(2), pp. 889-901 |
article | DOI URL |
Abstract: This paper considers the dynamic response and acoustic radiation of baffled rectangular plates elastically restrained against deflection and rotation along the four edges, and exposed to a half-space of dense fluid. Classical methods using in vacuo plate eigenfunctions to formulate the fluid/structure coupling are limited to the simply supported case and lead to considerable difficulty, both theoretical and numerical. The proposed method employs a variational formulation of the structural motion and a minimization process over a subspace of suitable displacement functions. The selection of simple polynomials to generate this subspace is shown to have many advantages: (i) it permits an analytic solution to be obtained for both the resistive and reactive components of the plate's radiation impedance, (ii) it furnishes a natural decomposition of the radiator into monopoles, dipoles,…, 2n-upoles, and (iii) it decreases the computation cost and increases the generality of the problem addressed, as compared to available methods. © 1994, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Berry1994889, author = {Berry, A.}, title = {A new formulation for the vibrations and sound radiation of fluid-loaded plates with elastic boundary conditions}, journal = {Journal of the Acoustical Society of America}, year = {1994}, volume = {96}, number = {2}, pages = {889-901}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0027933244&doi=10.1121%2f1.410264&partnerID=40&md5=474d8f05dee9875487bbd662ae3f1647}, doi = {https://doi.org/10.1121/1.410264} } |
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Champoux, Y., Oddo, R., Guigou, C. and Atalla, N. | On the noise of percussion drill steel rods | 1994 | Proceedings - National Conference on Noise Control Engineering, pp. 169-174 | conference | URL |
Abstract: We have described a test procedure which allows the examination of both vibration and acoustic behaviour of the flexural and longitudinal modes of a drill's steel rod. Imperfection tends to create double peaks for the flexural modes. Flexural and longitudinal waves are both contributing to the sound radiation. For a given force amplitude, the longitudinal mode amplitude seems to be insensitive to the impact force location. Flexural modes are very sensitive to imperfection of the rod and the impact force location. Boundary conditions will have an important effect on the flexural modes contributions. | |||||
BibTeX:
@conference{Champoux1994169, author = {Champoux, Y. and Oddo, R. and Guigou, C. and Atalla, N.}, title = {On the noise of percussion drill steel rods}, journal = {Proceedings - National Conference on Noise Control Engineering}, year = {1994}, pages = {169-174}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028022424&partnerID=40&md5=027d01773ac5cf9538f4da5cb2f22110} } |
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Charette, F., Guigou, C., Berry, A. and Plantier, G. | Asymmetric actuation and sensing of a beam using piezoelectric materials | 1994 | Journal of the Acoustical Society of America Vol. 96(4), pp. 2272-2283 |
article | DOI URL |
Abstract: This paper presents the development of a theoretical model and an experimental study for the response of a beam actuated by a ceramic piezoelectric on one side with a PVDF piezoelectric on the opposite side acting as a sensor. The two piezoelectric are of different types, may be of arbitrary length, and are positioned independently along the beam. Since the actuation is done by a single piezo on one side of the beam, an asymmetric excitation is applied to the beam that causes simultaneously extensional and flexural displacements. Both piezoelectric elements are considered perfectly bonded to the beam. The variational approach with Hamilton's principle is used to develop the theoretical model. This formulation, which is energy based, allows one to consider any boundary conditions at the ends of the beam and to take into account the dynamic effects (mass loading and stiffness) of both piezos on the beam response ignored in existing models. Experimental results are presented for the free-free boundary conditions. Those results show good agreement with the theoretical model and prove that the piezo's modify the mode shapes and natural frequencies of the beam. The changes in the mode shapes can be of vital importance in some applications. © 1994, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Charette19942272, author = {Charette, F. and Guigou, C. and Berry, A. and Plantier, G.}, title = {Asymmetric actuation and sensing of a beam using piezoelectric materials}, journal = {Journal of the Acoustical Society of America}, year = {1994}, volume = {96}, number = {4}, pages = {2272-2283}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0027940287&doi=10.1121%2f1.410099&partnerID=40&md5=03834dd9364169925edfffaf578be994}, doi = {https://doi.org/10.1121/1.410099} } |
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Guigou, C., Berry, A. and Charette, F. | Active control of plate volume velocity using shaped PVDF sensor | 1994 | American Society of Mechanical Engineers, Aerospace Division (Publication) AD Vol. 45, pp. 247-255 |
conference | URL |
Abstract: A design strategy for a PVDF sensor detecting the volume velocity induced by a vibrating 2D structure is presented for applications in ASAC. It is based on the modal representation of the plate response. It actually consists in designing a PVDF sensor composed of several PVDF strips bonded to the surface of the structure in such a way that the output signal of the sensor is directly proportional to the volume velocity. The design methodology is presented in the case of a simply supported plate but can be extended to any type of boundary conditions. For the studied plate, the sensor detects only contributions from the odd-odd modes, being the only ones with a non-zero volume velocity as well as being the most effective radiators. The efficiency of this type of PVDF volumetric sensor in ASAC is analytically evaluated as the radiated acoustic power and the radiation efficiency before and after control are studied. Experimental implementation of such a volumetric PVDF sensor is then presented and discussed. | |||||
BibTeX:
@conference{Guigou1994247, author = {Guigou, Catherine and Berry, Alain and Charette, Francois}, title = {Active control of plate volume velocity using shaped PVDF sensor}, journal = {American Society of Mechanical Engineers, Aerospace Division (Publication) AD}, year = {1994}, volume = {45}, pages = {247-255}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028733106&partnerID=40&md5=a8c23d014d566064d27023c216e326b8} } |
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Nicolas, J., Sgard, F., Atalla, N. and Labrecque, P. | Acoustic radiation of unbaffled structures [Rayonnement acoustique de structures non bafflees] | 1994 | Journal De Physique Vol. 4(5 pt 1), pp. 77-80 |
article | URL |
Abstract: If the simulation of the radiated field of a baffled plane structure has been deeply studied, the unbaffled case, although more realistic, has retained little attention. The proposed works tend to simulate, by an analytical approach, the radiation of a plane unbaffled structure of finite dimensions and general elastic type of boundary conditions. This approach is based on an integral method coupled with a Ritz approach for the calculus of the displacement field of the structure. The power is evaluated through the pressure jump across the plate. Translation and rotational springs create varying boundary conditions. A good comparison is found with a numerical approach (B.E.M.). Parametric studies showed the effect of the baffle. Precise measurements confirm the validity of the simulations. | |||||
BibTeX:
@article{Nicolas199477, author = {Nicolas, J. and Sgard, F. and Atalla, N. and Labrecque, P.}, title = {Acoustic radiation of unbaffled structures [Rayonnement acoustique de structures non bafflees]}, journal = {Journal De Physique}, year = {1994}, volume = {4}, number = {5 pt 1}, pages = {77-80}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028427698&partnerID=40&md5=070e9880e45bba0bcb3104400c7b51d3} } |
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Sgard, F., Atalla, N. and Nicolas, J. | Effects of a fluid in a uniform flow on the vibroacoustic behavior of a baffled plate coupled to a rectangular cavity [Effets d'un fluide en ecoulement uniforme sur le comportement vibro-acoustique d'une plaque bafflee couplee a une cavite rectangulaire] | 1994 | Journal De Physique Vol. 4(5 pt 2), pp. 1009-1012 |
conference | URL |
Abstract: The purpose of this work is to develop a general formulation to deal with the vibro-acoustic behavior of a baffled plate, immersed on one side in a mean flow and coupled on the other side to a rectangular cavity with arbitrary wall impedances. The plate is excited by a plane wave convected by the mean flow. The formulation is based on a finite element method for the calculation of the transverse vibrations of the plate and the acoustic field inside the cavity. The external fluid loading is accounted for through the extended Kirchoff-Helmoltz integral equation and the radiation impedance of the plate in the external fluid is computed with a boundary element method. The mean flow effects on the transmission loss of the plate are discussed. | |||||
BibTeX:
@conference{Sgard19941009, author = {Sgard, F. and Atalla, N. and Nicolas, J.}, title = {Effects of a fluid in a uniform flow on the vibroacoustic behavior of a baffled plate coupled to a rectangular cavity [Effets d'un fluide en ecoulement uniforme sur le comportement vibro-acoustique d'une plaque bafflee couplee a une cavite rectangulaire]}, journal = {Journal De Physique}, year = {1994}, volume = {4}, number = {5 pt 2}, pages = {1009-1012}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028425565&partnerID=40&md5=9fb20b79ee82c95901fa4edc29645699} } |
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Sgard, F., Atalla, N. and Nicolas, J. | Coupled FEM-BEM approach for mean flow effects on vibro-acoustic behavior of planar structures | 1994 | AIAA Journal Vol. 32(12), pp. 2351-2358 |
article | DOI URL |
Abstract: The originality of the present paper lies in the development of a formulation accounting for mean flow effects on the forced vibro-acoustic response of a baffled plate. The importance of these effects on the vibrational behavior of the plate, as well as on its acoustic radiation pattern, is investigated for a baffled plate with different kinds of boundary conditions. The analysis is based on a finite element method for the calculation of the plate transverse vibrations and the use of the extended Kirchhoff's integral equation to account for fluid loading with mean flow. A variational boundary element method is used to compute the acoustic radiation impedance. The formulation shows explicitly the effects of mean flow in terms of added mass, stiffness, and radiation damping. Details of the formulation as well as its numerical implementation are expounded, and results showing the effect of mean flow hi light and heavy fluid on the vibro-acoustic quantities, such as mean square velocity and radiated acoustic power, are presented. It is seen that the effects of a mean flow amount to a decrease of the natural frequencies of the plate, a small damping effect on the vibrations, and a change in the radiated acoustic power when compared with the no-flow case. Besides, these effects increase with the flow speed. The negative stiffness added by the flow is shown to be mainly responsible for the natural frequency shift effect. The changes in the radiated acoustic power are explained in terms of important changes in the radiation efficiencies and modal cross-coupling induced by the flow. © 1994 American Institute of Aeronautics and Astronautics, Inc., All rights reserved. | |||||
BibTeX:
@article{Sgard19942351, author = {Sgard, F. and Atalla, N. and Nicolas, J.}, title = {Coupled FEM-BEM approach for mean flow effects on vibro-acoustic behavior of planar structures}, journal = {AIAA Journal}, year = {1994}, volume = {32}, number = {12}, pages = {2351-2358}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028671357&doi=10.2514%2f3.12299&partnerID=40&md5=d4af278860f67760a792cfa4db8f18a8}, doi = {https://doi.org/10.2514/3.12299} } |
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Atalla, N. and Glegg, S.A. | Ray-acoustics approach to fuselage scattering of rotor noise | 1993 | Journal of the American Helicopter Society Vol. 38(3), pp. 56-63 |
article | URL |
Abstract: A ray acoustics approach to fuselage scattering of rotor noise is considered based on a combination of classical geometrical acoustics and the paraxial ray approximation. The method can handle scattering by objects of arbitrary shapes and can be applied in an inhomogeneous moving medium. Applications to aeroacoustics include the scattering of blade vortex interaction (BVI) pulses by rigid objects. The BVI is modeled by a rotating impulsive point force. It has been found that the scattering effects involving rotating sources cannot be ignored especially for sideline noise. Application to tilt-rotors has also shown the importance of the scattering effects by rectangular fuselages. | |||||
BibTeX:
@article{Atalla199356, author = {Atalla, Noureddine and Glegg, Stewart A.L.}, title = {Ray-acoustics approach to fuselage scattering of rotor noise}, journal = {Journal of the American Helicopter Society}, year = {1993}, volume = {38}, number = {3}, pages = {56-63}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0027629241&partnerID=40&md5=1f443b3b75262d17fa9b55c3850786d2} } |
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Champoux, Y. and Ross, M.J. | Measurement of thermal resistivity of insulating material using an acoustical technique | 1993 | Noise Control Engineering Journal Vol. 40(1), pp. 151-158 |
article | DOI URL |
Abstract: This paper describes a technique which makes possible the evaluation of the thermal resistance of fibrous thermal insulating materials using an acoustical measurement. This technique is based upon the evaluation of the propagation constant from the acoustical pressure transfer function across the material. A simple model is developed that takes advantage of the behavior of sound waves at the outlet of a baffled pipe. Experimental results obtained in the laboratory show a good correlation between the thermal resistance and the propagation constant. | |||||
BibTeX:
@article{Champoux1993151, author = {Champoux, Yvan and Ross, Marie Josee}, title = {Measurement of thermal resistivity of insulating material using an acoustical technique}, journal = {Noise Control Engineering Journal}, year = {1993}, volume = {40}, number = {1}, pages = {151-158}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0027222532&doi=10.3397%2f1.2827828&partnerID=40&md5=7ffed2d0ea912c1186d996acac32f666}, doi = {https://doi.org/10.3397/1.2827828} } |
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L'Espérance, A., Nicolas, J., Wilson, D., Thomson, D., Gabillet, Y. and Daigle, G. | Sound propagation in the atmospheric surface layer: Comparison of experiment with FFP predictions | 1993 | Applied Acoustics Vol. 40(4), pp. 325-346 |
article | DOI URL |
Abstract: This paper presents a set of acoustical and meteorological data from an outdoor sound propagation experiment. This experiment was done in a farm field near Rock Springs, Pennsylvania, on 7 July 1990. Meteorological and acoustical measurements were recorded simultaneously during six different times in the day. The meteorological measurements permitted determination of the sound speed profiles during each of the measurement sessions, using a method based on surface-layer similarity scaling. The acoustical measurements allowed precise determination of the relative sound pressure levels for a frequency range up to 3150 Hz at six different distances (66, 88, 125, 175, 250 and 350 m). The results show atmospheric conditions have an important effect on sound propagation. At medium and high frequencies, variations of the relative SPL have been measured at distances as short as 62 m. These effects increased with the distances so that variations as great as 30 dB have been measured during that day. Comparisons with the fast field program predictions are also presented, and amply demonstrate the accuracies of this model, especially for the downward refraction cases. © 1993. | |||||
BibTeX:
@article{L'Espérance1993325, author = {L'Espérance, A. and Nicolas, J. and Wilson, D.K. and Thomson, D.W. and Gabillet, Y. and Daigle, G.}, title = {Sound propagation in the atmospheric surface layer: Comparison of experiment with FFP predictions}, journal = {Applied Acoustics}, year = {1993}, volume = {40}, number = {4}, pages = {325-346}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0027316483&doi=10.1016%2f0003-682X%2893%2990092-K&partnerID=40&md5=2b7dc967209c2b2b0f741689c4658fd8}, doi = {https://doi.org/10.1016/0003-682X(93)90092-K} } |
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Panneton, R., L'Espèrance, A., Nicolas, J. and Daigle, G. | Development and validation of a model predicting the performance of hard or absorbent parallel noise barriers | 1993 | Journal of the Acoustical Society of Japan (E) (English translation of Nippon Onkyo Gakkaishi) Vol. 14(4), pp. 251-258 |
article | DOI URL |
Abstract: This paper deals with the development and the validation of a model used to evaluate the performance of parallel noise barrier configuration. These barriers are generally used to reduce the noise emitted by traffic roads. The formulation and algorithm used combine the multiple reflections occuring between the parallel barriers by the acoustical imagery method, and the barriers absorption by the modified Delany-Bazley impedance model. They also take into account parallel barriers with different heights, the ground effect, and a spectral sound power for various type of traffic noise. A complex summation between acoustical waves originating from a single source is used to obtain rigorously constructive and destructive acoustical interferences. This approach has been validated against systematic experimentations in controlled conditions in a semi-anechoic room. A case study is also presented which highlights the importance of applying absorbent materials on the barriers in terms of an increase in efficiency. © 1993, Acoustical Society of Japan. All rights reserved. | |||||
BibTeX:
@article{Panneton1993251, author = {Panneton, R. and L'Espèrance, A. and Nicolas, J. and Daigle, G.A.}, title = {Development and validation of a model predicting the performance of hard or absorbent parallel noise barriers}, journal = {Journal of the Acoustical Society of Japan (E) (English translation of Nippon Onkyo Gakkaishi)}, year = {1993}, volume = {14}, number = {4}, pages = {251-258}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0346990588&doi=10.1250%2fast.14.251&partnerID=40&md5=175e042b5e33e3e71d47413ee37c5887}, doi = {https://doi.org/10.1250/ast.14.251} } |
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Piaud, J.-B., Nicolas, J. and Loyau, T. | Kinetic energy transfer in a plane network of beams | 1993 | Transactions of the Canadian Society for Mechanical Engineering Vol. 17(3), pp. 389-409 |
article | URL |
Abstract: This paper deals with the problem of the effect upon the average kinetic energy of each beam contained within a plane network of beams, brought about by alterations to the network. A junction model having three degrees of freedom has been developed to take into account the response of the structure of both longitudinal and flexural motions. The driving forces to be used are white noise excitations of a given bandwidth. The method employed for the evaluation of the kinetic energy is analogous to the method of energy influence coefficients, which allows one to identify the contribution of each excitation to the energy of every beam in the structure. It is shown that modifications in the geometry, such as a change in cross section or a change in the angle between two beams, can lead to good results if the frequency bandwidth of the excitations contains few global modes. Alterations relating to the stiffness and the damping of a junction between two beams, which make possible the dynamic damping of one of the beams, yield substantial gains with respect to vibration. | |||||
BibTeX:
@article{Piaud1993389, author = {Piaud, J.-B. and Nicolas, J.R. and Loyau, T.J.}, title = {Kinetic energy transfer in a plane network of beams}, journal = {Transactions of the Canadian Society for Mechanical Engineering}, year = {1993}, volume = {17}, number = {3}, pages = {389-409}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0027806408&partnerID=40&md5=3630ea856e4e82365c581c260d373031} } |
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Atalla, N. and Nicolas, J. | Formulation for mean flow effects on sound radiation from rectangular baffled plates with arbitrary boundary conditions | 1992 | American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA Vol. 13, pp. 69-84 |
conference | URL |
Abstract: A general formulation of the sound radiation from fluid-loaded rectangular baffled plates with arbitrary boundary conditions has been developed by Berry et al (J.A.S.A. Vol.90(4), Pt.2, 1991). In this paper, an extension of this formulation to inviscid, uniform subsonic flow is considered. The analysis is based on a variational formulation for the transverse vibrations of the plate and the use of the extended, to uniformly moving media, form of the Helmholtz integral equation. The formulation shows explicitly the effect of the flow in terms of added mass, and radiation resistance. Furthermore, it avoids the difficult problem of integration in the complex domain, typical of the wavenumber transform approaches to fluid-loading problems. Comparison of the acoustic radiation impedance with existing studies supports the validity of the approach. The details of the formulation and its numerical implementation is exposed and a preliminary discussion of the flow effects on the radiation impedance of a rectangular piston is presented. | |||||
BibTeX:
@conference{Atalla199269, author = {Atalla, Noureddine and Nicolas, Jean}, title = {Formulation for mean flow effects on sound radiation from rectangular baffled plates with arbitrary boundary conditions}, journal = {American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA}, year = {1992}, volume = {13}, pages = {69-84}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0026989723&partnerID=40&md5=a0d99d8d801facf2252673fab1e4abd7} } |
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Champoux, Y. and Stinson, M. | On acoustical models for sound propagation in rigid frame porous materials and the influence of shape factors | 1992 | Journal of the Acoustical Society of America Vol. 92(2 I), pp. 1120-1131 |
article | DOI URL |
Abstract: The propagation of sound in rigid-frame porous materials saturated with air is studied experimentally and theoretically. Two existing theoretical models, the Attenborough and the Biot-Allard models, are first evaluated using measured characteristic impedances and propagation constants for samples of ceramic material. The Biot-Allard model is found to give good agreement to the measured data if a single, frequency-independent shape factor is introduced. The Attenborough model, though, requires a shape factor that has a significant frequency dependence. To provide a more stringent test, we have constructed a model porous material that has large variations in pore cross-sectional area. This sample contains 373 straight cylindrical pores whose diameters alternate between 0.025 and 0.154 cm along their lengths. Both the Biot-Allard and Attenborough models are unable to describe the measured acoustical properties for this sample. A simple theoretical model is proposed that describes the propagation of sound through pores whose cross-sectional area and shape change along the course of each pore in a known fashion. Very good agreement between experimental results and the theoretical predictions for the two-diameter model is found. It is demonstrated that the dynamic density function (that describes the viscous effects) is associated more with the narrow sections of the pores and the dynamic bulk modulus (describing the thermal effects) is associated more with the wider sections of the pores. This theoretical model for arbitrary materials can then be generalized. Two different shape factors are required, in general, to describe both the viscous and thermal effects. | |||||
BibTeX:
@article{Champoux19921120, author = {Champoux, Y. and Stinson, M.R.}, title = {On acoustical models for sound propagation in rigid frame porous materials and the influence of shape factors}, journal = {Journal of the Acoustical Society of America}, year = {1992}, volume = {92}, number = {2 I}, pages = {1120-1131}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0026731887&doi=10.1121%2f1.405281&partnerID=40&md5=59a2ccbf016b379908e1d1f6997574f1}, doi = {https://doi.org/10.1121/1.405281} } |
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Cheng, L. and Nicolas, J. | Radiation Of Sound Into A Cylindrical Enclosure From A Point-Driven End Plate With General Boundary Conditions | 1992 | Journal of the Acoustical Society of America Vol. 91(3), pp. 1504-1513 |
article | DOI URL |
Abstract: The radiation of sound from a point-driven circular plate into a hard-walled cylindrical enclosure is investigated. Emphasis is given on studying the effects of the boundary conditions of the plate, which are modeled as a continuous distribution of edge springs acting against both the deflection and the rotation of the contour of the plate. With this model, both classical and intermediate boundary cases can be simulated by adjusting the elastic stiffness of the springs. A coupled acoustoelastic formulation is developed following a variational approach, with the use of hard-walled cavity modes. In the analysis, the full interaction between the structure vibration and the internal cavity sound pressure is considered. Numerical results indicate that a significant reduction in noise inside the cavity can be obtained for a relatively wide frequency range by completely relaxing the translational support (zero deflection stiffness) of the plate. This is mainly due to a weakening of the modal radiation efficiency of the flexural modes of the plate. With an increase of the deflection stiffness on the contour of the plate, this beneficial frequency range is shifted to higher frequencies. It is hoped that the findings of the present work will be useful for practical predictions of airplane cabin noise emitted by the rear pressure bulkhead, as well as for noise control in some aerospace structures and mechanical systems involving cylindrical-shaped cavities. © 1992, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Cheng19921504, author = {Cheng, L. and Nicolas, J.}, title = {Radiation Of Sound Into A Cylindrical Enclosure From A Point-Driven End Plate With General Boundary Conditions}, journal = {Journal of the Acoustical Society of America}, year = {1992}, volume = {91}, number = {3}, pages = {1504-1513}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0026762828&doi=10.1121%2f1.402482&partnerID=40&md5=66b2cfeec88f8f2e879ec13a07d9e57e}, doi = {https://doi.org/10.1121/1.402482} } |
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Cheng, L. and Nicolas, J. | Free vibration analysis of a cylindrical shell-circular plate system with general coupling and various boundary conditions | 1992 | Journal of Sound and Vibration Vol. 155(2), pp. 231-247 |
article | DOI URL |
Abstract: The free vibration of a structure consisting of a finite circular cylindrical shell closed at one end by a circular plate is analyzed in this paper. Emphasis is given to the characterization of structural coupling and boundary conditions. These are incorporated into the model by means of continuous distributions of springs along the shell and the plate interface. A general formulation based on a variational principle is used. This formulation allows a wide spectrum of boundary conditions and coupling conditions between the shell and the plate, an issue the importance of which is clearly shown by a literature review. Very good accuracy of the method is demonstrated by solving test problems for lower order modes of the plate and of the shell, for which some results are available in the literature. Comparisons are also made using finite element analysis on a plate-ended shell, showing that the proposed approach is a convenient, effecient and accurate one for determining the modal behavior of such a complex structural system. Other numerical results are then presented for a shell rigidly attached to a plate, to illustrate the coupling phenomena between the shell and the plate. It is shown that there exist three different types of modes for this combined structure; they are termed plate-controlled modes, shell-controlled modes and strongly coupled modes, respectively. It is also shown that each type is closely related to the modal character of each of uncoupled elements. © 1992. | |||||
BibTeX:
@article{Cheng1992231, author = {Cheng, L. and Nicolas, J.}, title = {Free vibration analysis of a cylindrical shell-circular plate system with general coupling and various boundary conditions}, journal = {Journal of Sound and Vibration}, year = {1992}, volume = {155}, number = {2}, pages = {231-247}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-38249011846&doi=10.1016%2f0022-460X%2892%2990509-V&partnerID=40&md5=fb2d6686b2a8aa739eb5d7de469f2eb7}, doi = {https://doi.org/10.1016/0022-460X(92)90509-V} } |
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L'Espérance, A., Nicolas, J., Herzog, P. and Daigle, G. | Heuristic model for outdoor sound propagation based on an extension of the geometrical ray theory in the case of a linear sound speed profile | 1992 | Applied Acoustics Vol. 37(2), pp. 111-139 |
article | DOI URL |
Abstract: In the case of outdoor sound propagation at relatively short ranges, it is reasonable to assume that sound follows straight ray paths. At longer ranges, refraction due to temperature and wind gradients results in ray paths that are curved, and calculations using straight rays are no longer valid and lead to erroneous results. In addition, atmospheric turbulence plays an ever-increasing role by degrading the coherence of the sound field. In this paper, the theory valid for propagation from a point source above an impedance plane is extended to include the effects of curved rays and the loss of coherence due to atmospheric turbulence. The model assumes a sound speed gradient that varies linearly with height above the ground. This assumption allows an analytical determination of the travel times of the curved rays and the modified angle of incidence of the ground-reflected paths. The additional reflected rays that may appear in the presence of a positive gradient are included in the calculation. The assumption also permits the determination of the position of the shadow zone in the presence of a negative gradient. The total sound pressure level is computed by summing the contribution from all the rays. In this summation, a fluctuating index of refraction is used to take into account the partial coherence between the rays caused by the effects of atmospheric turbulence. If the receiver is in the shadow zone, a diffraction theory based on a residue series solution is used to compute the sound levels. The results of calculations using the model are compared with experimental results. © 1992. | |||||
BibTeX:
@article{L'Espérance1992111, author = {L'Espérance, A. and Nicolas, J.R. and Herzog, P. and Daigle, G.A.}, title = {Heuristic model for outdoor sound propagation based on an extension of the geometrical ray theory in the case of a linear sound speed profile}, journal = {Applied Acoustics}, year = {1992}, volume = {37}, number = {2}, pages = {111-139}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0027064827&doi=10.1016%2f0003-682X%2892%2990022-K&partnerID=40&md5=98a74613e846157364c8b11fbebeb57f}, doi = {https://doi.org/10.1016/0003-682X(92)90022-K} } |
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Laura, P., Ercoli, L., Berry, A., Guyader, J.-L. and Nicolas, J. | Comments on 'A general formulation for the sound radiation from rectangular, baffled plates with arbitrary boundary conditions' [Berry et al., J. Acoust. Soc. Am. 88, 2792-2802 (1990)] | 1992 | Journal of the Acoustical Society of America Vol. 92(5), pp. 2990-2991 |
article | DOI URL |
Abstract: The recent, excellent article 'A general formulation for the sound radiation from rectangular, baffled plates with arbitrary boundary conditions,' by A. Berry, J. L. Guyader, and J. Nicolas [J. Acoust. Soc. Am. 88, 2792-2802 (1990)] calls for some remarks and clarifications concerning use of polynomial functions when dealing with free and forced vibrations of plates. | |||||
BibTeX:
@article{Laura19922990, author = {Laura, P.A.A. and Ercoli, L. and Berry, A. and Guyader, J.-L. and Nicolas, J.}, title = {Comments on 'A general formulation for the sound radiation from rectangular, baffled plates with arbitrary boundary conditions' [Berry et al., J. Acoust. Soc. Am. 88, 2792-2802 (1990)]}, journal = {Journal of the Acoustical Society of America}, year = {1992}, volume = {92}, number = {5}, pages = {2990-2991}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0026458273&doi=10.1121%2f1.404366&partnerID=40&md5=d8e0f86f7c94e3a4fc695a5109e563f6}, doi = {https://doi.org/10.1121/1.404366} } |
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Laville, F. and Nicolas, J. | A computer simulation of sound power determination using two-microphone sound intensity measurements [BibTeX] |
1992 | Journal of the Acoustical Society of America Vol. 91(4), pp. 2042-2055 |
article | DOI URL |
BibTeX:
@article{Laville19922042, author = {Laville, F. and Nicolas, J.}, title = {A computer simulation of sound power determination using two-microphone sound intensity measurements}, journal = {Journal of the Acoustical Society of America}, year = {1992}, volume = {91}, number = {4}, pages = {2042-2055}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0026752104&doi=10.1121%2f1.403690&partnerID=40&md5=03dc182f10d0ba9e9f3b88a10db0cbf3}, doi = {https://doi.org/10.1121/1.403690} } |
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Nicolas, J. | State of the art on the prediction of the noise emitted by vibrating structures, viewed by the first European congress on the subject [BibTeX] |
1992 | Applied Acoustics Vol. 35(4), pp. 325-331 |
article | DOI URL |
BibTeX:
@article{Nicolas1992325, author = {Nicolas, J.}, title = {State of the art on the prediction of the noise emitted by vibrating structures, viewed by the first European congress on the subject}, journal = {Applied Acoustics}, year = {1992}, volume = {35}, number = {4}, pages = {325-331}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0026692333&doi=10.1016%2f0003-682X%2892%2990059-2&partnerID=40&md5=aaa8b87e1c479f5ae65f3bf29a5db671}, doi = {https://doi.org/10.1016/0003-682X(92)90059-2} } |
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Stinson, M. and Champoux, Y. | Propagation of sound and the assignment of shape factors in model porous materials having simple pore geometries | 1992 | Journal of the Acoustical Society of America Vol. 91(2), pp. 685-695 |
article | DOI URL |
Abstract: The acoustical properties of a class of simple porous materials have been studied experimentally and theoretically. Rigid-frame materials containing air-filled pores of uniform cross section were investigated. Two model porous materials were constructed, one with pores of rectangular cross section (0.0146x0.0172 cm) and one with pores of triangular cross section (0.037-cm sides). The characteristic impedance and propagation constant were measured for frequencies between 50 and 4500 Hz and good agreement with exact theoretical predictions was obtained. The exact theoretical expressions for specific pore shapes (e.g., slitlike, square, and triangular) can be used to investigate the assignment of shape factors by various general but approximate theoretical models. It is demonstrated that the model introduced by Attenborough requires a shape factor that is frequency dependent. A theoretical model, appropriate for materials containing pores of uniform cross section, that correctly treats the low- and high-frequency behavior, is presented. Given subsidiary measurements of flow resistivity, porosity, and tortuosity, a single shape factor leads to very good agreement with the exact solutions for all frequencies. © 1992, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Stinson1992685, author = {Stinson, M.R. and Champoux, Y.}, title = {Propagation of sound and the assignment of shape factors in model porous materials having simple pore geometries}, journal = {Journal of the Acoustical Society of America}, year = {1992}, volume = {91}, number = {2}, pages = {685-695}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0026753365&doi=10.1121%2f1.402530&partnerID=40&md5=891593504bb7e4bdb9cae37ab0be0275}, doi = {https://doi.org/10.1121/1.402530} } |
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Atalla, N. and Glegg, S.A. | Ray-acoustics approach to fuselage scattering of rotor noise | 1991 | Annual Forum Proceedings - American Helicopter Society, pp. 841-853 | conference | URL |
Abstract: A ray acoustics approach to fuselage scattering of rotor noise is considered based on a combination of classical geometrical acoustics and the paraxial ray approximation. The method can handle scattering by objects of arbitrary shapes and can be applied in an inhomogeneous moving medium. Applications to aeroacoustics include the scattering of blade vortex interaction (BVI) pulses by rigid objects. The BVI is modelled by a rotating impulsive point force. It has been found that the scattering effects of rotating sources cannot be ignored especially for sideline noise. Application to tilt-rotors has also shown the importance of the scattering effects by rectangular fuselages. | |||||
BibTeX:
@conference{Atalla1991841, author = {Atalla, Noureddine and Glegg, Stewart A.L.}, title = {Ray-acoustics approach to fuselage scattering of rotor noise}, journal = {Annual Forum Proceedings - American Helicopter Society}, year = {1991}, pages = {841-853}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0025799326&partnerID=40&md5=0ae67e43cb95e3325d52884a93d7e80e} } |
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Champoux, Y. and Allard, J.-F. | Dynamic tortuosity and bulk modulus in air-saturated porous media | 1991 | Journal of Applied Physics Vol. 70(4), pp. 1975-1979 |
article | DOI URL |
Abstract: In this paper, the concept of characteristic length introduced in the definition of the dynamic tortuosity by Johnson, Koplik, and Dashen [J. Fluid Mech. 176, 379 (1987)] is extended to express the frequency dependence of the bulk modulus of the saturating fluid at high frequencies. A general phenomenological frequency dependence for this dynamic bulk modulus is obtained using the expression for the dynamic tortuosity. The theoretical predictions for dynamic tortuosity and bulk modulus are compared with experimental results obtained from acoustic measurements on a rigid-frame porous material saturated with air. | |||||
BibTeX:
@article{Champoux19911975, author = {Champoux, Y. and Allard, J.-F.}, title = {Dynamic tortuosity and bulk modulus in air-saturated porous media}, journal = {Journal of Applied Physics}, year = {1991}, volume = {70}, number = {4}, pages = {1975-1979}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-21544461078&doi=10.1063%2f1.349482&partnerID=40&md5=dacb512ca9e757669caa51337bc14996}, doi = {https://doi.org/10.1063/1.349482} } |
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Champoux, Y., Stinson, M. and Daigle, G. | Air-Based System For The Measurement Of PorosityA | 1991 | Journal of the Acoustical Society of America Vol. 89(2), pp. 910-916 |
article | DOI URL |
Abstract: An experimental system for the measurement of porosity, the volume fraction of air contained in a material, is described. Porosity is important as one of several parameters required by acoustical theory to characterize a porous material. As with the technique described by Beranek [J. Acoust. Soc. Am. 13, 248–260 (1942)], the isothermal pressure change in a closed volume containing a sample material is measured for a known change in the volume. The volume of air contained in the sample, and hence the porosity, is inferred from these two quantities. The new system, though, avoids the use of liquids, either directly in the technique or for temperature stabilization. Instead, a piston of accurately known diameter is used to produce the change in volume, and the change in pressure is measured with an electronic pressure transducer. Model calculations and measurements on real materials confirm that porosity can be measured rapidly and conveniently with this apparatus, with an accuracy of better than 1% over a broad range of sample volumes and porosities. © 1991, Acoustical Society of America. All righrs reserved. | |||||
BibTeX:
@article{Champoux1991910, author = {Champoux, Y. and Stinson, M.R. and Daigle, G.A.}, title = {Air-Based System For The Measurement Of PorosityA}, journal = {Journal of the Acoustical Society of America}, year = {1991}, volume = {89}, number = {2}, pages = {910-916}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0026093447&doi=10.1121%2f1.1894653&partnerID=40&md5=a5ca38da1be5909517fedd19cbfd3f42}, doi = {https://doi.org/10.1121/1.1894653} } |
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Ouellet, D. and Nicolas, J. | Sound field in a rectangular cavity in the presence of a thin, flexible obstacle by the integral equation method | 1991 | Journal of the Acoustical Society of America Vol. 89(5), pp. 2131-2139 |
article | DOI URL |
Abstract: This paper is concerned with the prediction of the sound field in a cavity enclosing a thin, flexible obstacle and having finite impedance boundaries. The formulation uses the integral equation method adapted to consider a thin obstacle. It also makes use of the equation of motion of the obstacle, but the only form given here is for the case of a limp panel. The solution is achieved by expressing all the required functions as modal expansions in the equations defining the problem. The set of eigenfunctions of an empty, rigid-walled rectangular cavity is used as a basis for the expansions, which restricts the final solution to rectangular cavities. A few numerical results are presented to validate the theory on some aspects related to simple cases of plane obstacles in rigid-walled cavities. © 1991, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Ouellet19912131, author = {Ouellet, D. and Nicolas, J.}, title = {Sound field in a rectangular cavity in the presence of a thin, flexible obstacle by the integral equation method}, journal = {Journal of the Acoustical Society of America}, year = {1991}, volume = {89}, number = {5}, pages = {2131-2139}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0025844922&doi=10.1121%2f1.400906&partnerID=40&md5=1953a0f13fb1d5ad992133da91e1dbb2}, doi = {https://doi.org/10.1121/1.400906} } |
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Berry, A., Nicolas, J. and Guyader, J.-L. | A general formulation for the sound radiation from rectangular, baffled plates with arbitrary boundary conditions | 1990 | Journal of the Acoustical Society of America Vol. 88(6), pp. 2792-2802 |
article | DOI URL |
Abstract: The radiation of sound from a baffled, rectangular plate with edges elastically restrained against deflection and rotation is analyzed. The elastic constants along the contour can be varied to reproduce simply supported, clamped, free, or guided edges as limiting cases. The formulation is based on a variational method for the vibration of the plate, and assumes no fluid loading of the structure. The elastic boundary conditions appear in the Hamiltonian of the plate through a dynamic contribution, which is expressed in terms of nondimensional edge parameters. The extremalization of the Hamiltonian is achieved using a Rayleigh-Ritz method, and both the free vibrations and the forced vibrations of the plate are presented. The radiation of sound from the plate is analyzed in the far field, and is calculated from one-dimensional Fourier transforms. Numerical results are presented for the radiation efficiency of modes of simply supported, clamped, free, and guided plates. The values found agree well with predictions of Wallace in the simply supported case, and of Gomperts in the guided case. It is found that a low deflection stiffness at the edges decreases the radiation efficiency of the elastic modes in a spectacular manner. The radiation efficiency of the rigid modes of the plate is derived analytically in low frequencies. It is seen that, when rigid motion of the plate is permitted, it is responsible for almost all the acoustical power radiated. The new case of a plate which is locally clamped along its four edges is also presented. © 1990, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Berry19902792, author = {Berry, A. and Nicolas, J. and Guyader, J.-L.}, title = {A general formulation for the sound radiation from rectangular, baffled plates with arbitrary boundary conditions}, journal = {Journal of the Acoustical Society of America}, year = {1990}, volume = {88}, number = {6}, pages = {2792-2802}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0025646497&doi=10.1121%2f1.399682&partnerID=40&md5=761ada13cb1ee349f074b42c45ed170f}, doi = {https://doi.org/10.1121/1.399682} } |
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Champoux, Y. and Richarz, W. | An aid in the numerical integration for in situ acoustic impedance and absorption coefficient measurements | 1990 | Journal of the Acoustical Society of America Vol. 87(4), pp. 1809-1812 |
article | DOI URL |
Abstract: A method to measure in situ the surface acoustic impedance of a material was recently introduced by Allard and Champoux [Noise Control Eng. J. 32 (1), 15–23 (1988)]. It requires the utilization of a numerical method based on the well-known fixed-point method. This numerical method is shown to yield sufficiently precise results regardless of the value of the surface impedance. Using an alternative expression for the complex integral that is evaluated numerically, values for the upper integration and summation limits are determined to make the in situ method viable in practice. © 1990, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Champoux19901809, author = {Champoux, Y. and Richarz, W.G.}, title = {An aid in the numerical integration for in situ acoustic impedance and absorption coefficient measurements}, journal = {Journal of the Acoustical Society of America}, year = {1990}, volume = {87}, number = {4}, pages = {1809-1812}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0025046252&doi=10.1121%2f1.399378&partnerID=40&md5=43f5be4b1d1776cb43dab99092a066de}, doi = {https://doi.org/10.1121/1.399378} } |
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Nicolas, J., Sawan, M., Hetu, R. and Laroche, C. | Digitally controlled impulse-noise generation system for the study of the ear response to impulses | 1990 | Acustica Vol. 70(2), pp. 112-126 |
article | URL |
Abstract: A new experimental tool is proposed to study the auditory effects of impulse noise. It allows systematic variation of the key parameters characterizing an impulse signal. These parameters are reviewed as well as the different generation methods previously used. The proposed method is based upon a computerized digital signal fed into a high power electroacoustic system. A two step numerical calculation controls the output signal to obtain the desired time and frequency characteristics. In the first step, the equipment transfer function is computed numerically. In the second step the input signal is corrected using the previously determined transfer function to obtain the desired output signal. The experimental setup includes a key element a D/A converter specially designed for the accurate generation of the impulsive signals necessary for temporary threshold shift (TTS) analysis. An illustration of the use of the system for the study of temporary threshold shift is presented. The comparison of the growth curves of TTS for 4 different signals provide clear indications concerning the effects of the spectral content and of the pressure time profile of short duration impulses. | |||||
BibTeX:
@article{Nicolas1990112, author = {Nicolas, J. and Sawan, M. and Hetu, R. and Laroche, C.}, title = {Digitally controlled impulse-noise generation system for the study of the ear response to impulses}, journal = {Acustica}, year = {1990}, volume = {70}, number = {2}, pages = {112-126}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0025387340&partnerID=40&md5=69c47ad296ec0974bc9c40185a2e19a0} } |
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Allard, J. and Champoux, Y. | In situ two-microphone technique for the measurement of the acoustic surface impedance of materials | 1989 | Noise Control Engineering Journal Vol. 32(1), pp. 15-23 |
article | DOI URL |
Abstract: A method of measuring surface impedance in situ is presented. It is shown that this method can account for the close proximity of the sound source to the surface being investigated. Measurements of the acoustic surface impedance of a carpet and a sheet of glass wool were performed using this method in an anechoic room, in a small non-anechoic room, and in a large cafeteria. For strongly absorbing materials, the surface impedance measurements can be performed with this method in small or large non-anechoic rooms. For weakly-absorbing materials, measurements are possible for medium and high frequencies in either a large room or an anechoic room, but in a small non-anechoic room. | |||||
BibTeX:
@article{Allard198915, author = {Allard, J.F. and Champoux, Yvan}, title = {In situ two-microphone technique for the measurement of the acoustic surface impedance of materials}, journal = {Noise Control Engineering Journal}, year = {1989}, volume = {32}, number = {1}, pages = {15-23}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0024305162&doi=10.3397%2f1.2827724&partnerID=40&md5=9c2aa545c8b398e02f7ba2a87c7c617a}, doi = {https://doi.org/10.3397/1.2827724} } |
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L'Espérance, A., Nicolas, J. and Daigle, G. | Insertion loss of absorbent barriers on ground | 1989 | Journal of the Acoustical Society of America Vol. 86(3), pp. 1060-1064 |
article | DOI URL |
Abstract: This paper presents a method for calculating the insertion loss (IL) of a thin barrier covered with absorbent material, either on the source side, on the receiver side, or on both sides. The method used combines a classical theory for the propagation of sound over ground with an approximate solution for diffraction around an absorbent barrier, which can take into account the specific impedance of each side of the barrier. The validity of the method was confirmed by comparing theoretical results with experimental measurements for various geometrical configurations and screen boundary conditions. The results show that, when the angles of diffraction are significant, the insertion loss (IL) of a hard barrier can be substantially increased by covering one of its surfaces with an absorbent material. This absorbent layer must be placed on the surface of the barrier associated with the greatest angle of the diffracted rays paths (source top-edge or receiver top-edge). When these angles are about the same on each side of the barrier, the increase will be the same if the absorbent material is placed on the source or on the receiver side. In this case, by covering both sides of the barrier, the increase of the IL due to the absorbent will double compared to a single covering. © 1989, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{L'Espérance19891060, author = {L'Espérance, A. and Nicolas, J. and Daigle, G.A.}, title = {Insertion loss of absorbent barriers on ground}, journal = {Journal of the Acoustical Society of America}, year = {1989}, volume = {86}, number = {3}, pages = {1060-1064}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0000547987&doi=10.1121%2f1.398097&partnerID=40&md5=0ff8fe07d17089852ce0ce6190803092}, doi = {https://doi.org/10.1121/1.398097} } |
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Lemire, G. and Nicolas, J. | Aerial propagation of spherical sound waves in bounded spaces | 1989 | Journal of the Acoustical Society of America Vol. 86(5), pp. 1845-1853 |
article | DOI URL |
Abstract: The idea of using the method of complex image sources to model spherical sound-wave propagation in bounded spaces is reexamined in the light of the work of Gensane and Santon [J. Sound Vib. 63, 97–108 (1979) ]. Use has been made of recent progress in the field of spherical sound-wave reflection. Calculations have been carried out in three simple spaces: a space limited by two infinite parallel planes (layer), a rectangular waveguide, and a rectangular enclosure. The results of predictions by the image-source method are compared to those of wave theory for frequencies from 60 to 1000 Hz in spaces whose characteristic dimension ranges from 0.7 to 11 m. The results indicate that the image-source model generally agrees within a few tenths of a dB with the wave theory in the cases of the layer, rectangular waveguide, and rectangular enclosure. The agreement between the two models is somewhat worse when the source-to-receiver distance is large compared with the dimension of the space, and when the source is close to a highly absorbent edge of the space. Except for these extreme cases, the complex image-source method is a valuable tool for studying the propagation of sound in bounded spaces, even at low frequencies in the audio range. © 1989, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Lemire19891845, author = {Lemire, G. and Nicolas, J.}, title = {Aerial propagation of spherical sound waves in bounded spaces}, journal = {Journal of the Acoustical Society of America}, year = {1989}, volume = {86}, number = {5}, pages = {1845-1853}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0009948953&doi=10.1121%2f1.398563&partnerID=40&md5=f35fcff7e5478789fa560e959343cda9}, doi = {https://doi.org/10.1121/1.398563} } |
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Loyau, T., Piaud, J. and Nicolas, J. | Kinetic energy transfer in plane beam-structure | 1989 | American Society of Mechanical Engineers, Design Engineering Division (Publication) DE Vol. 18-3, pp. 57-63 |
conference | URL |
Abstract: In this paper, we analyse the kinetic energy repartition in plane beam-structure. For that, authors use a similar method like Energy Influence Coefficient method (E.I.C.), but they use the wave approach instead of modal approach. Authors have elaborate a junction model with three degrees of freedom to describe the behaviour of the junction for the two longitudinal and flexural sollicitations. A parametrical analysis allows us to find the most important characteristics for the reduction of kinetic energy. They have shown that, for narrow band excitations, a change of the angle or a change of the beam section could be efficient. For wide band excitations, only structural damping is really efficient. | |||||
BibTeX:
@conference{Loyau198957, author = {Loyau, T.J. and Piaud, J.B. and Nicolas, J.R.}, title = {Kinetic energy transfer in plane beam-structure}, journal = {American Society of Mechanical Engineers, Design Engineering Division (Publication) DE}, year = {1989}, volume = {18-3}, pages = {57-63}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0024887828&partnerID=40&md5=827e623dbea0bb5235a7f54ddecf01f0} } |
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Berry, A. and Daigle, G. | Controlled experiments of the diffraction of sound by a curved surface | 1988 | Journal of the Acoustical Society of America Vol. 83(6), pp. 2047-2058 |
article | DOI URL |
Abstract: Controlled measurements of the sound field from a point source above a curved surface are described. The measurements were made in the frequency range between 0.3 and 10 kHz, in the case of a rigid boundary and a surface of finite impedance. Receiver positions include all of the area within, and above, the shadow zone and for various source heights. Particular attention is given to the region across the shadow boundary. The measurements are compared to diffraction theory expressed in terms of a residue series, or creeping wave solution. The calculation is extended by removing restrictive approximations and by carrying the computation to higher-order terms. A numerical algorithm allows the extension to the general case of a finite impedance. Above the shadow boundary, the sound field is calculated using geometrical theory that accounts for reflections from a curved surface. Deep within the shadow, theory and measurements agree to, typically, 0.5 dB. The same agreement is obtained between measurements and the geometrical theory well above the shadow boundary. In the vicinity of the shadow boundary, both theories agree to within 0.5 dB but differ from the measured results by 2 to 5 dB. Finally, the theory is compared to measurements obtained outdoors above a grass covered curved ground with no refraction and above flat ground with refraction. © 1988, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Berry19882047, author = {Berry, A. and Daigle, G.A.}, title = {Controlled experiments of the diffraction of sound by a curved surface}, journal = {Journal of the Acoustical Society of America}, year = {1988}, volume = {83}, number = {6}, pages = {2047-2058}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0024023143&doi=10.1121%2f1.396385&partnerID=40&md5=5599ac09e944bfcc90f239e8ccaedc51}, doi = {https://doi.org/10.1121/1.396385} } |
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Champoux, Y. and L'Espérance, A. | Numerical evaluation of errors associated with the measurement of acoustic impedance in a free field using two microphones and a spectrum analyzer | 1988 | Journal of the Acoustical Society of America Vol. 84(1), pp. 30-38 |
article | DOI URL |
Abstract: This article investigates numerically several sources of errors associated with the measurement of acoustic impedance using the two-microphone method in a free field. This method is based on the evaluation of the acoustic velocity from the pressure gradient. For impedance measurement, the finite approximation, phase mismatch, effective microphone separation, and probe localization errors are analyzed. Once it is known how to calculate the exact impedance above an absorbing plane, the influence of the assumed wave propagation type on the calculation of the material impedance is then investigated. Finally, an example of the useful range of validity of the method is presented. © 1988, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Champoux198830, author = {Champoux, Y. and L'Espérance, A.}, title = {Numerical evaluation of errors associated with the measurement of acoustic impedance in a free field using two microphones and a spectrum analyzer}, journal = {Journal of the Acoustical Society of America}, year = {1988}, volume = {84}, number = {1}, pages = {30-38}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0023693458&doi=10.1121%2f1.396986&partnerID=40&md5=ebb0a65d7830c2f759c70828f95cb23d}, doi = {https://doi.org/10.1121/1.396986} } |
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Champoux, Y., Nicolas, J. and Allard, J. | Measurement of acoustic impedance in a free field at low frequencies | 1988 | Journal of Sound and Vibration Vol. 125(2), pp. 313-323 |
article | DOI URL |
Abstract: Methods for measuring acoustic impedance in a free field using two microphones are given. It is found to be possible, by using these methods, to measure impedances at frequencies as low as 250 Hz. To obtain a sufficient precision at these frequencies it is necessary to use pure tone signals and to increase the microphone separation distance. The effect of the distance from the source to the material on measurement of the normal surface impedance of absorbing materials is also demonstrated. © 1988. | |||||
BibTeX:
@article{Champoux1988313, author = {Champoux, Y. and Nicolas, J. and Allard, J.F.}, title = {Measurement of acoustic impedance in a free field at low frequencies}, journal = {Journal of Sound and Vibration}, year = {1988}, volume = {125}, number = {2}, pages = {313-323}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-38249028123&doi=10.1016%2f0022-460X%2888%2990286-6&partnerID=40&md5=de4cffb868467d365de728ab8b9c8932}, doi = {https://doi.org/10.1016/0022-460X(88)90286-6} } |
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Sidki, M. and Nicolas, J. | Localization of coherent and incoherent sound sources via an optimization process | 1988 | Journal of the Acoustical Society of America Vol. 84(2), pp. 639-644 |
article | DOI URL |
Abstract: The problem of the localization and characterization of sound sources is discussed, for the case of a set of monopole sources, starting with the analytic expressions describing the field in combination with a gradient method for the optimization process. To locate the sources, three measurement variables are used: the 3-D vectorial active intensity, the normal active intensity, and the mean-square pressure. Simulations for three emitting sources, aimed at predicting their positions and spectral densities, are made. The minimum number of measurement positions that lead to convergence of the algorithm is investigated. The agreement between prediction and reality is good even when the sources are coherent. In parallel, the impact of the choice of measurement variable on the precision of the results is studied. In the very near field of the source, it is found that identification via 3-D intensimetry requires a significantly lower number of measurement positions than does that via normal intensity or mean-square pressure. © 1988, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Sidki1988639, author = {Sidki, M. and Nicolas, J.}, title = {Localization of coherent and incoherent sound sources via an optimization process}, journal = {Journal of the Acoustical Society of America}, year = {1988}, volume = {84}, number = {2}, pages = {639-644}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84955015985&doi=10.1121%2f1.396842&partnerID=40&md5=a1b259958e3fa324f17922c516e1f5fa}, doi = {https://doi.org/10.1121/1.396842} } |
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Allard, J., Champoux, Y. and Depollier, C. | Modelization of layered sound absorbing materials with transfer matrices | 1987 | Journal of the Acoustical Society of America Vol. 82(5), pp. 1792-1796 |
article | DOI URL |
Abstract: A method is presented that allows the prediction of the acoustical properties of layered porous or fibrous materials in normal incidence from simple measurements. Transfer matrices obtained from the Biot theory are used to describe homogeneous layers and screens constituting layered materials. The description of an absorbing material with the method is given. © 1987, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Allard19871792, author = {Allard, J.F. and Champoux, Y. and Depollier, C.}, title = {Modelization of layered sound absorbing materials with transfer matrices}, journal = {Journal of the Acoustical Society of America}, year = {1987}, volume = {82}, number = {5}, pages = {1792-1796}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0006975506&doi=10.1121%2f1.395796&partnerID=40&md5=79568338b4c042f037ebd9d822f61ebf}, doi = {https://doi.org/10.1121/1.395796} } |
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Legouis, T. and Nicolas, J. | Phase gradient method of measuring the acoustic impedance of materials | 1987 | Journal of the Acoustical Society of America Vol. 81(1), pp. 44-50 |
article | DOI URL |
Abstract: A free-field method using a point source has been developed to measure the normal specific impedance of porous materials. The phase gradient is measured as a function of distance along the normal to the materials passing through the point source. The phase gradient is obtained from a two-microphone probe. The phase and amplitude of the complex reflection coefficient are used as constants adjusted for the best fit to experimental results using a standard optimization technique. Results are obtained on layers of fiberglass and polyurethane foam in the frequency range between 250 and 400 Hz. Good agreement is found when the measured results are compared to the predictions of Delany and Bazley [Appl. Acoust. 3, 105-116 (1970)]. The method has the advantages of requiring a minimum of instrumentation and is particularly adapted to measurements at low frequencies. © 1987, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Legouis198744, author = {Legouis, T. and Nicolas, J.}, title = {Phase gradient method of measuring the acoustic impedance of materials}, journal = {Journal of the Acoustical Society of America}, year = {1987}, volume = {81}, number = {1}, pages = {44-50}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0002712551&doi=10.1121%2f1.394931&partnerID=40&md5=3577a83c4d02e9553bf7e6055bcacee6}, doi = {https://doi.org/10.1121/1.394931} } |
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Nicolas, J. and Lemire, G. | Modern techniques for noise control identification | 1987 | Pulp and Paper Canada Vol. 88(1), pp. 38-41 |
article | URL |
Abstract: Noise source identification methods are often the key tools for establishing the most economical and rapid ways of reducing noise at its source. This paper discusses such methods with emphasis on the advantages and possibilities which sound intensity measurements have over classical techniques. The use of intensimetry to identify the dominant noise source in situ is a promising tool for the pulp and paper industry.
Noise source identification methods are often the key tools for establishing the most economical and rapid ways of reducing noise at its source. This paper discusses such methods with emphasis on the advantages and possibilities which sound intensity measurements have over classical techniques. The use of intensimetry to identify the dominant noise source in situ is a promising tool for the pulp and paper industry. |
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BibTeX:
@article{Nicolas198738, author = {Nicolas, J. and Lemire, G.}, title = {Modern techniques for noise control identification}, journal = {Pulp and Paper Canada}, year = {1987}, volume = {88}, number = {1}, pages = {38-41}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0023202342&partnerID=40&md5=ad882f7d97a3480841d334ca5ec4961f} } |
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Nicolas, J. and L'Esperance, A. | BARRIER INSERTION LOSS INSIDE INDUSTRIAL HALLS. | 1986 | Vol. 1, pp. 519-524 |
conference | URL |
Abstract: The modelling of barrier insertion loss involves three steps: a) calculation of the direct and reflected fields before installation of the barrier; b) calculation of purely diffracted waves; and c) calculation of a mixed diffracted and reflected field. The image method can be used to predict the insertion loss of a partial or full width barrier independently of the relative position of the sources, receiver and barrier in the room and of the absorption coefficient of each wall. The method is valid in three finite dimensions. | |||||
BibTeX:
@conference{Nicolas1986519, author = {Nicolas, Jean and L'Esperance, A.}, title = {BARRIER INSERTION LOSS INSIDE INDUSTRIAL HALLS.}, year = {1986}, volume = {1}, pages = {519-524}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0022999447&partnerID=40&md5=9d2e23436daed3e7686f14b5dac16cb3} } |
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Nicolas, J. | Experimental study of a slow-waveguide barrier on finite impedance ground | 1986 | Journal of the Acoustical Society of America Vol. 80(3), pp. 869-876 |
article | DOI URL |
Abstract: A slow-waveguide filter consisting of an open network of rigid strips is used to modify a conventional noise barrier. The acoustical performance of the resulting device relies on the interference between the field diffracted by the barrier edge and the field propagating through the waveguide. The possibilities of enhancing low-frequency noise reduction with this device is studied experimentally. in addition, limitations in the existing waveguide model are removed and the theory is extended to allow for reflections due to the presence of the ground. Both theory and experiments show that, at frequencies where significant destructive interference occurs between the diffracted field and the field transmitted through the waveguide, there is an enhanced noise reduction. However, at adjacent frequencies there is constructive interference which can degrade the performance of the barrier. © 1986 Acoustical Society of America | |||||
BibTeX:
@article{Nicolas1986869, author = {Nicolas, J.}, title = {Experimental study of a slow-waveguide barrier on finite impedance ground}, journal = {Journal of the Acoustical Society of America}, year = {1986}, volume = {80}, number = {3}, pages = {869-876}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0022475273&doi=10.1121%2f1.393910&partnerID=40&md5=976396e0f6b0a88e831b0ce618ec34d5}, doi = {https://doi.org/10.1121/1.393910} } |
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Piaud, J. and Nicolas, J. | Relationship between vibrational and acoustical intensity for an infinite plate | 1986 | Journal of the Acoustical Society of America Vol. 80(4), pp. 1114-1121 |
article | DOI URL |
Abstract: The vibrational intensity is compared to the acoustical intensity in the general case of any flexural progressive wave, using the geometrical optics theory applied to the farfield of a thin plate. The vibrational and acoustical intensities are obtained using that theory. They are shown to be equivalent when the acoustical intensity is measured near and parallel to the plate. The theoretical expression for the vibrational intensity suggests a simple method of measurement using two accelerometers. The validity of the method is analyzed in the theoretical case of the mechanical excitation of an infinite plate by a point force and by a force moment. Experimental results are shown to validate the theoretical predictions. © 1986, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Piaud19861114, author = {Piaud, J.B. and Nicolas, J.}, title = {Relationship between vibrational and acoustical intensity for an infinite plate}, journal = {Journal of the Acoustical Society of America}, year = {1986}, volume = {80}, number = {4}, pages = {1114-1121}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952124800&doi=10.1121%2f1.393801&partnerID=40&md5=2215e4a22e1f8988ee0905946d428666}, doi = {https://doi.org/10.1121/1.393801} } |
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Daigle, G., Nicolas, J. and Berry, J.-L. | Propagation of noise above ground having an impedance discontinuity | 1985 | Journal of the Acoustical Society of America Vol. 77(1), pp. 127-138 |
article | DOI URL |
Abstract: Controlled measurements above ground with an impedance discontinuity are described. The measurements were made outdoors with a source above asphalt and a receiver above grass, and indoors above surfaces of known impedance in the absence of atmospheric turbulence. The results were obtained for several sources and receiver heights and for various percentages of hard-soft ground to propagation distances of 2.4 m indoors and 10 m outdoors. The measurements are also extended to include the case of a source above ground of finite impedance but which is still harder than the ground on the receiver side. The measurements are compared with recent theory which includes semiempirical solutions and solutions obtained numerically from Green's theorem. Good agreement between the measured results and all the theories is obtained in most cases. However, in more extreme situations, including the “soft-softer” ground case, the semiempirical solutions are in difficulty. Earlier work [Nicolas et al., J. Acoust. Soc. Am. 73, 44-54 (1983)] is also extended by calculating the insertion loss of a barrier on ground with an impedance discontinuity. The previously measured insertion loss is recompared with the predicted insertion loss and good agreement is now obtained. © 1985, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Daigle1985127, author = {Daigle, G.A. and Nicolas, J. and Berry, J.-L.}, title = {Propagation of noise above ground having an impedance discontinuity}, journal = {Journal of the Acoustical Society of America}, year = {1985}, volume = {77}, number = {1}, pages = {127-138}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0021834385&doi=10.1121%2f1.392276&partnerID=40&md5=0d684cb7195dd284f325e3985a775ddf}, doi = {https://doi.org/10.1121/1.392276} } |
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Lemire, G.R. and Nicolas, J. | IMAGE METHOD PREDICTION OF INDUSTRIAL HALL NOISE LEVELS - A NEW ALGORITHM. | 1985 | Noise control engineering Vol. 24(2), pp. 58-67 |
article | URL |
Abstract: The image method is often used to predict sound levels within enclosures. One of the drawbacks of this method is the lengthy computation time involved. This paper describes the basis of a new algorithm which permits the researcher optimum use of this computation time. In addition, this method also enables one to take into account a rough estimate of the source directivity and the extra sound attenuation due to the obstacle effect produced by the surrounding machines or reflectors. This paper applies the new algorithm to a weaving shed. 20 refs. | |||||
BibTeX:
@article{Lemire198558, author = {Lemire, Gilles R. and Nicolas, Jean}, title = {IMAGE METHOD PREDICTION OF INDUSTRIAL HALL NOISE LEVELS - A NEW ALGORITHM.}, journal = {Noise control engineering}, year = {1985}, volume = {24}, number = {2}, pages = {58-67}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0022027708&partnerID=40&md5=b91a32834a9cea5cfcb5c93a731340dc} } |
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Nicolas, J. and Lemire, G. | Precision of active sound intensity measurements in a progressive and a nonprogressive field | 1985 | Journal of the Acoustical Society of America Vol. 78(2), pp. 414-422 |
article | DOI URL |
Abstract: The estimated sound intensity is compared to the exact intensity in order to study the precision of active sound intensity measurement, for the cases of a simple progressive field and any sort of nonprogressive fields. The progressive field is produced by an harmonic monopole, whereas the nonprogressive field is produced by two harmonic monopoles of variable strength ratio and geometric conditions. The analysis is performed in the time domain. In the progressive field case, a general formulation of the error is obtained which simplifies in limiting cases to forms already published in the literature. In the nonprogressive field case, emphasis is put on the formulation of the exact phase gradient and of the total pressure field resulting from the two sources. The formulation of the uncertainty points out considerable errors at low frequencies due to instrumental phase mismatch and at high frequencies due to finite approximation of amplitude and of the phase gradient. Finally, the ratio of the sound intensity to the pressure as an indicator of the accuracy of sound intensity measurement is discussed. © 1985, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Nicolas1985414, author = {Nicolas, J. and Lemire, G.}, title = {Precision of active sound intensity measurements in a progressive and a nonprogressive field}, journal = {Journal of the Acoustical Society of America}, year = {1985}, volume = {78}, number = {2}, pages = {414-422}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0008955384&doi=10.1121%2f1.392463&partnerID=40&md5=3f0ae9b1d6975ee9594ff22574389da6}, doi = {https://doi.org/10.1121/1.392463} } |
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Nicolas, J., Berry, J.-L. and Daigle, G. | Propagation of sound above a finite layer of snow | 1985 | Journal of the Acoustical Society of America Vol. 77(1), pp. 67-73 |
article | DOI URL |
Abstract: Measurements of the sound field from a point source above a relatively soft surface layer backed by an acoustically hard material are reported. These were made outdoors over layers of snow from 5 to 50 cm thick and to propagation distances of up to 15 m. The conditions of the snow layer varied from newly fallen to aged and windblown snow. Experiments were also conducted indoors at shorter distances above reticulated foam of similar thicknesses. The theory of Pyett [Acustica 3, 375–382 (1953)] for the acoustic impedance of a porous layer is used to extend the solution for reflection of spherical waves from a porous half-plane to reflection from a porous layer. This simple theory shows good agreement with the indoor measurements at all frequencies. Similarly good agreement between this theory and experiments over snow layers outdoors is obtained above about 200 to 500 Hz depending on the geometrical configuration. However below these frequencies the measurements suggest that the layer of snow behaves as semi-infinite porous ground. © 1985, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Nicolas198567, author = {Nicolas, J. and Berry, J.-L. and Daigle, G.A.}, title = {Propagation of sound above a finite layer of snow}, journal = {Journal of the Acoustical Society of America}, year = {1985}, volume = {77}, number = {1}, pages = {67-73}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0021784986&doi=10.1121%2f1.391902&partnerID=40&md5=c5d7b3e730067933b16b745fbad9a2f0}, doi = {https://doi.org/10.1121/1.391902} } |
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Nicolas, J. and Lemire, G. | MODERN TECHNIQUES FOR NOISE SOURCE IDENTIFICATION. [BibTeX] |
1984 | , pp. 1-6 | conference | URL |
BibTeX:
@conference{Nicolas19841, author = {Nicolas, Jean and Lemire, Gilles}, title = {MODERN TECHNIQUES FOR NOISE SOURCE IDENTIFICATION.}, year = {1984}, pages = {1-6}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0021290607&partnerID=40&md5=8e98a049b29258de5a6b2572cf8bdba3} } |
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Nicolas, J., Embleton, T. and Piercy, J. | Authors’ reply to “Comments on ‘Precise model measurements versus theoretical prediction of barrier insertion loss in presence of the ground’-” | 1983 | Journal of the Acoustical Society of America Vol. 74(4), pp. 1300-1301 |
article | DOI URL |
Abstract: It is explained, through quotations from several previously published papers, that the deviations of several curves in the cited paper are due to the elimination of one of two partially compensating theoretical approximations. © 1983, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Nicolas19831300, author = {Nicolas, J. and Embleton, T.F.W. and Piercy, J.E.}, title = {Authors’ reply to “Comments on ‘Precise model measurements versus theoretical prediction of barrier insertion loss in presence of the ground’-”}, journal = {Journal of the Acoustical Society of America}, year = {1983}, volume = {74}, number = {4}, pages = {1300-1301}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84955014677&doi=10.1121%2f1.390049&partnerID=40&md5=0de5aefeee5dd5cd2ecf98e82fbd5f52}, doi = {https://doi.org/10.1121/1.390049} } |
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Nicolas, J., Benoit, R. and Sauve, S. | NOISE SOURCE IDENTIFICATION AND REDUCTION IN A CHOCOLATE PLANT. | 1983 | Proceedings - National Conference on Noise Control Engineering, pp. 339-342 | conference | URL |
Abstract: Noise reduction in a chocolate plant is considered. Huge machinery is very often unique and dedicated to one specific product. A careful investigation of the dominant noise shows that very frequent impacts are the major problem. For operation and ranking of the sources, acoustic intensity measurements have been made. A face to face configuration has been used in order to evaluate with precision the pressure gradient up to 8 kHz: this was required by the high frequency contents of the metal to metal type of impact. The two noisiest departments happened to be: the marshmallow production with mainly the guillotine and the mixing rotating drum; and the shell and solid bars production with a great number of sources: vibrating systems for the mixture of chocolate, taken from the mold with metal to metal impact, ringing noise from the conveyor hydraulic pumping station, speed reducer, pneumatic valves, cryogenic head carrier and ventilation. Each of these sources have been tackled keeping in mind practical in-situ solutions thanks to systematic study of noise generation mechanisms. | |||||
BibTeX:
@conference{Nicolas1983339, author = {Nicolas, J. and Benoit, R. and Sauve, S.}, title = {NOISE SOURCE IDENTIFICATION AND REDUCTION IN A CHOCOLATE PLANT.}, journal = {Proceedings - National Conference on Noise Control Engineering}, year = {1983}, pages = {339-342}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0020870597&partnerID=40&md5=6e30ca008dfcd98550f4e5381542ccbe} } |
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Nicolas, J., Embleton, T. and Piercy, J. | Precise model measurements versus theoretical prediction of barrier insertion loss in presence of the ground | 1983 | Journal of the Acoustical Society of America Vol. 73(1), pp. 44-54 |
article | DOI URL |
Abstract: Recent work on barrier performance, aimed at quantifying effects due to interference and scattering by atmospheric turbulence, has also indicated systematic deviations between measured results of diffraction and those predicted by widely used theories embodying known approximations. Model experiments indoors (no atmospheric turbulence and a known, controllable ground impedance) show systematic deviations, independent of frequency, up to 12 dB when compared with either first-order approximations of Macdonald’s diffraction theory or that of Kirchhoff. More exact evaluation of the diffraction integral [e.g., Hadden and Pierce, J. Acoust. Soc. Am. 69, 1266–1276 (1981)] or diffraction theory based on layer potential theory [e.g., Daumas, Acustica 40, 212–222 (1978)] provide agreement with measured results within ±1.5 dB under all experimental configurations investigated. An empirical correction based solely on such geometrical considerations as distance of source and receiver to the barrier and height of barrier, i.e., on the value of the angle of diffraction at the edge of the barrier, provides similarly good agreement. To obtain precise theoretical predictions of barrier performance under a wide range of configurations it is suggested that one use either calculations based on the recent formulation of Hadden and Pierce or some simple approximate theory plus this empirical correction based on diffraction angle. © 1983, Acoustical Society of America. All rights reserved. | |||||
BibTeX:
@article{Nicolas198344, author = {Nicolas, J. and Embleton, T.F.W. and Piercy, J.E.}, title = {Precise model measurements versus theoretical prediction of barrier insertion loss in presence of the ground}, journal = {Journal of the Acoustical Society of America}, year = {1983}, volume = {73}, number = {1}, pages = {44-54}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0020542131&doi=10.1121%2f1.388722&partnerID=40&md5=65f324e890052c17e3920f133d733585}, doi = {https://doi.org/10.1121/1.388722} } |
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Nicolas, J., Lapointe, J., Benoit, R. and Gosselin, B. | In Situ Measurement of Acoustic Absorption Coefficient by the Impulse Method and Digital Processing. [MESURE IN SITU DU COEFFICIENT D'ABSORPTION ACOUSTIQUE PAR METHODE IMPULSIVE ET TRAITEMENT DIGITAL.] [BibTeX] |
1981 | CANCAM Proceedings - Canadian Congress of Applied Mechanics Vol. 2, pp. 693-694 |
conference | URL |
BibTeX:
@conference{Nicolas1981693, author = {Nicolas, Jean and Lapointe, Jean and Benoit, R. and Gosselin, B.}, title = {In Situ Measurement of Acoustic Absorption Coefficient by the Impulse Method and Digital Processing. [MESURE IN SITU DU COEFFICIENT D'ABSORPTION ACOUSTIQUE PAR METHODE IMPULSIVE ET TRAITEMENT DIGITAL.]}, journal = {CANCAM Proceedings - Canadian Congress of Applied Mechanics}, year = {1981}, volume = {2}, pages = {693-694}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0019653286&partnerID=40&md5=1f43855ac2e9e3130042a85edbe4692c} } |
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Nicolas, J. and Champoux, Y. | ON LINE FREQUENCY SENSITIVE CORRECTION FOR IMPACT TESTING. | 1980 | Instrumentation in the Pulp and Paper Industry, Proceedings Vol. 2, pp. 54-57 |
article | URL |
Abstract: A dynamic calibration of the analog transient signals from impact identification testing of structures is developed using computer programming. Emphasis is put on the experimental procedures of calibration and how to avoid errors introduced by the analog to digital conversion in the data acquisition system. The experimental setup consisted of a free pendulum, on which mass an impulsive force is imposed by the test hammer. | |||||
BibTeX:
@article{Nicolas198054, author = {Nicolas, J.R. and Champoux, Y.C.}, title = {ON LINE FREQUENCY SENSITIVE CORRECTION FOR IMPACT TESTING.}, journal = {Instrumentation in the Pulp and Paper Industry, Proceedings}, year = {1980}, volume = {2}, pages = {54-57}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0019283890&partnerID=40&md5=e7986dad5aa9635328d5b14077b173d2} } |