Interior structure-borne noise reduction by controlling the automotive body panel vibration

Abstract

The adoption of a numerical method to perform vibration and acoustic analyses is attracting increasing attention because of its merits in saving costs and time. The analysis flow chart of structure-borne noise reduction by controlling the vehicle body panel vibration is proposed. A finite element analysis of a body in white is performed according to this flow chart, using MSC. Nastran, and the experimental modal analysis of a body in white is also carried out. To verify the finite element model, a correlation analysis between the test and the finite element results is performed. After the acoustic boundary element model with seats has been constructed, the acoustic transfer vector is calculated using LMS software. A transfer path analysis is performed to estimate the powertrain and exhaust pipe operational forces at idle. Then the forces are input into the acoustic boundary element model to calculate the body panel velocity. By combining the acoustic transfer vector and the body panel velocity, the interior acoustic response can be obtained. The simulation results are verified by tests. To determine the main contribution panels for the interior sound pressure level, a panel acoustic contribution analysis is based on the boundary element method. Finally, constrained damping treatments are adopted to control the main panel vibration based on the results of the panel acoustic contribution analysis. The test results indicate that the sound pressure level of the interior noise at idle is reduced obviously before and after treatments, which has proved the correctness of the results from the panel acoustic contribution analysis. Therefore it is believed that the proposed analysis method is feasible for reducing interior structure-borne noise.