Coupling of FEM and Exterior/Interior Acoustic Field with BEM and Numerical Simulation of Vibro-Acoustic Response of Elastic Target

The numerical research of vibro-acoustic response to fluid-structure-fluid coupling system caused by acoustic loading needs to be conducted with the help of reliable structural finite element and acoustic boundary element to complete the fluid-structure-fluid coupling calculation. In this paper, discrete Kirchoff quadrilateral (DKQ) bending element and constant strain quadrilateral (CSQ) membrane element is adopted to construct DKQ-CSQ shell element of high accuracy. Therefore, a BEM-FEM numerical solution method of high accuracy is created. With this method, the vibro-acoustic response to the acoustic loading on a shell which is not only surrounded by but also filled with fluid can be solved. Numerical calculations of spherical shell are carried out, and the accuracy of the method is verified in this paper. The influence of different fluid media on echo intensity and structural vibration mode are analyzed in detail.