Attenuation of acoustic waves and mechanical vibrations at low frequencies by a nonlinear dynamical absorber

Abstract : At the present time, the attenuation of acoustic waves and mechanical vibrations at high and middle frequencies is well known and easily done, especially with dissipative materials. However, this attenuation is much more difficult to realize at low frequencies because of the large wavelengths. In the work presented here, we propose to reduce the noise and the vibrations at low frequency over a broad frequency band by means of nonlinear absorbers allowing a transfer and a dissipation of the energy. These absorbers are randomly arranged in a matrix and have a nonlinear dynamical behavior. The absorber consists of a cantilever beam supporting a concentrated mass at its end. It is designed in order to obtain a nonlinear dynamical behavior in the low-frequency band due to the finite displacements of the beam. This mechanical system is modeled by a mass-spring-damping system with a nonlinear stiffness and a nonlinear damping. Indeed, nonlinearity allows attenuation over a broader frequency band, unlike linear systems which only generate a reduction over a narrow frequency band around the resonance, which makes it possible to reduce the number of absorbers needed for a given attenuation .We will first present the design of the nonlinear absorber optimized using stochastic modeling in order to obtain the most adequate nonlinear response possible. Then, experimental results will be presented as well as their comparisons with the numerical predictions. Then, we present the modeling and numerical homogenization of a beam containing several randomly distributed nonlinear absorbers and their effective dissipation. This will be compared with the results of the experimental analysis of this system.
Type de document :
Communication dans un congrès
USNCCM 2017, 14th U. S. National Congress on Computational Mechanics, Jul 2017, Montreal, Canada
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https://hal-upec-upem.archives-ouvertes.fr/hal-01566420
Contributeur : Christian Soize <>
Soumis le : vendredi 21 juillet 2017 - 09:21:32
Dernière modification le : vendredi 22 juin 2018 - 10:44:23

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  • HAL Id : hal-01566420, version 1

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Deborah Lavazec, Gwendal Cumunel, Denis Duhamel, Christian Soize. Attenuation of acoustic waves and mechanical vibrations at low frequencies by a nonlinear dynamical absorber. USNCCM 2017, 14th U. S. National Congress on Computational Mechanics, Jul 2017, Montreal, Canada. 〈hal-01566420〉

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