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This paper describes a method to separate structure-borne noise, which comes from the shock absorber, from the measured vehicle interior sound pressure. The transfer path analysis (TPA) was used. Shock absorber was considered as an input source while the sound pressure at the driver seat as its output. It was found that the sound pressure at the driver seat position and accelerations at the shock absorber mounting points are strongly correlated. Using one-third octave band analysis, the contribution of shock absorber structure-borne noise to the driver seat sound pressure was analyzed. Also the relationship between the measured acceleration and sound pressure was studied.

An accurate vehicle structural vibration analysis, in medium or high frequency range, is necessary for structural redesign to reduce the vehicle interior noise, however, FE analyses in those frequency ranges are usually inaccurate. To overcome this difficulty, a guide for using experimental data instead of finite analysis results was studied. Formulations for the sensitivity of FRFs and harmonic responses are derived, and a structure-acoustic coupling analysis in modal domain was done to cure the structure-bone noise problem. Also, a technique for determining the proper modification positions or regions for reducing the interior noise level is suggested and tested both numerically and experimentally with a 1/2 scale vehicle model.