The Influence of Non-Local Property of Surface Acoustic Impedance on Acoustic Scattering

Abstract

The Influence of Non-local Property of Surface Acoustic Impedance on Acoustic Scattering is investigated in this paper. Firstly, an equivalent acoustic impedance model, proposed by Faverjon, has been put into acoustic sc attering calculation. Combined with Spectral Collocation Boundary Element Method , ,, , the theoretical deduction of acoustic scattering calculation has been conducted and the s cattering of sphere covered with sound- absorbing materials has been calculated. The influe nce of different parameters used in the equivalent acoustic impedance model on the acoustic scattering is discussed. At last, take a certain kind of viscoelastic material for an exampl e, by finite element method calculate the response from an exciting to get the parameters of local and non-local acoustic impedance in the model, the results shown the model is reasonabl e. All of that illustrates that the non-local property of acoustic impedance has a great effect o n acoustic scattering and it needs to be focused on. I. Introduction coustic impedance is the most important acoustic pr operty of the surface sound-absorbing materials. Ac oustic impedance model offers a simplified method to describe the sound-absorbing property of materials. At p resent, many works have already been published about local impedance concerning underwater anechoic tile or aero-engine liner 1 . Nevertheless, many sound-absorbing materials present non-local property, and they are being concerned. In reference, a kind of equivalent non-local acoustic impedance model, proposed by Faverjon 2,3 , has been used to study the sound transmission though multilayer system. The context of this research is devoted to establish the concept of equivalent non-local acoustic impedance and a simil ar semi-physical model in acoustic scattering calcu lation. The model has been used to calculate the scattering of sphere covered with sound-absorbing materials by boundary integration method. The influence of different para meters used in the model on the acoustic scattering is discussed. A response of viscoelastic material from an exiting is calculated by finite element method, the result s validate the model.