COUPLED FINITE ELEMENT/BOUNDARY ELEMENT METHOD FOR THE ANALYSIS OF THE ACOUSTIC SCATTERING FROM ELASTIC STRUCTURES

摘要

Considerable interest has been expressed recently in the scattering of acoustic waves from elastic targets. For structures of arbitrary shapes, the numerical method relying upon a finite element description of the solid part and a boundary element description of the waves propagating in the infinite fluid medium is the most commonly used. This paper presents a coupling between the ATILA finite element code and the EQI boundary element code performed using a solid variable methodology. Results are presented for a thin cylindrical shell bounded by hemispherical endcaps which are insonifled at axial and normal incidences. Comparisons are made with measurements of backscattered pressure spectra and angular patterns obtained with the quasi-harmonic MIIR (Method of Isolation and Identification of Resonances). Emphasis is put on post-processing techniques contributing to the interpretation of physical phenomena such as the extraction of resonant mode shapes.