Booming Noise Analysis in a Passenger Car Using a Hybrid-Integrated Approach 2000-01-0723

A hybrid-integrated approach is presented to analyze the structure-borne booming noise in a passenger car. We identify the critical noise transfer path from the engine to the target by the transfer path analysis. However, it does not give the answer for why the noise transfer function is so high at that path. Therefore, an integrated approach which applies the analysis tools systematically is presented. The running mode analysis gives us the operating motion of each component in the body structure. However, there is no evidence that the components that vibrate severely are the sources of this problem. The modal characteristics from the structural modal test enable us to describe the real motion of the body completely in terms of the structural modes. Similarly, the acoustic modal characteristics from the acoustic modal analysis describe the fundamental behavior of the cabin cavity. The introduction of the experimental running mode data of the structure to the acoustic finite element model makes the hybrid analysis possible. Through the structural and the acoustic modal analysis, we verify the mode that contributes to the booming noise. The panel contribution analysis points out the components that have the greatest influence on the booming noise. The modification of the body based on the results of the hybrid-integrated approach results in the great decrease of the noise level.