Research And CAE Analysis On Structure-borne Noise Of Automobile Passenger Compartment

To a certain vehicle, CAE simulation analysis and control were made to the interior low-frequency Structure-borne noise by using existing mature CAE analysis software based on numerical methods such as FEM,BEM etc and modal analysis method. The interior noise was improved by optimizing structure.Research works were made as follows:1. FE model of the BIW (body-in-white) was built and updated by comparing results of calculated and experimental modal analysis. On this basis, a full body FE model with doors and windows was built, so as the interior acoustic FE and BE models.2. Frequency response analysis was taken to the BIW structure. Then interior sound field frequency response was calculated by extracting the velocity response of the structure as the boundary condition. Also a preliminary coupling analysis was made to the coupled model. Through these analyses, response characteristics of the sound field and the peak response frequencies were found.3. Panel contribution analysis was made at those frequencies where peak values were found. Then panels which had a large contribution to the sound pressure of focused points could be found out in order to set target for the structural optimization.4. Taking panel vibration control as the target, dynamic sensitivity analysis was carried out to some panels'thickness. Optimization analysis was made to these variables which had a high sensitivity to the target.5. According to the optimization results, structure was improved. Then comparison between the interior noise levels before and after improvement was made to assess the effectiveness of the improvement.