Hybrid finite element-wave based method for acoustic prediction

• 1、School of Automotive Engineering,Chongqing University,Chongqing 400030

Abstract：The FEM(Finite Element Method) has the characteristics of geometric adaptability, but low computational efficiency with the increase of the analysis frequency, while the WBM(Wave Based Method) has the properties of high convergence rate but poor geometric flexibility. To combine the flexibility of FEM for complex geometries and of the computational efficiency of WBM,the hybrid coupling FE-WBM is proposed by applying normal velocity and acoustic pressure continuity conditions at the interface between FE domian and WB domian. Taking the vehicle cavity as an example, the FE-WBM model of a 2D interior cavity is established, and the vehicle sound pressure prediction is realized. The sound pressure nephograms at 600Hz and 900Hz and the frequency-response characteristic of the response point within 1000Hz of the FE-WBM are compared with those of the reference FEM. The results show that FE-WBM matches well with the reference FEM, which shows the effectiveness of FE-WBM. Taking the degree of freedom of the model and the running time of the CPU as independent variables respectively, while the relative error of response point as dependent variables, the convergence curves shows that the FE-WBM has a clear advantage over the traditional FEM in terms of the degree of freedom of the model and the running time of the CPU at the same error level.

Keywords： acoustic prediction wave based method finite element method finite element-wave based method