3C12 Theory and Method on the Prediction of Car Interior Noise Combined FEM with BEM

Abstract

It is very important to predict the interior noise of automobile for the assessment and enhancement of NVH performance in the design stage. For the analysis of middle and low frequency noise, the Finite Element Method (FEM) and Boundary Element Method (BEM) are usually employed. In this paper, the interior noise of automobile is predicted based on FEM and BEM, and the panel acoustic contribution is calculated. Firstly, the theories of FEM and BEM are studied comprehensively, the governing equation of the coupled acoustic-structural FEM is derived based on the second kind Lagrangian equation of nonconservative system, and the acoustic boundary integral equation is derived through Green's theorem; then, the finite element and boundary element models of body and acoustic cavity of passenger compartment are built respectively, the acoustic responses are obtained through FEM and BEM simulation; the linear correlation coefficient is introduced to assess the relations between the two results; finally, the Panel Acoustic Contribution Analysis (PACA) is carried out, through which the panels contributing more to the interior noise are identified, and the foundation for the structural optimization to reduce the vibration of panels and interior noise level of automobile is laid.