Analytical method for vehicle interior noise using principal component contribution -Identification of resonance frequency in cabin at the operational condition utilizing principal component transfer function-

Principal component (PC) contribution analysis utilizing operational TPA was developed to evaluate high contributing vibration behavior of the target structure such as vehicle body. However, not only the vibration characteristic but also acoustic characteristic in cabin had better to be focused for more effective countermeasure. In this study, we attempted to identify the main factor increasing the interior noise between body vibration and cabin acoustic characteristics. In the test, a simple vehicle model was employed and vibration at multiple points around the body and interior noise were measured. Subsequently, PC contribution to the interior noise was calculated by multiplying PC level and PC transfer function. We then focused the PC level and the transfer function of the highest PC contribution. We estimated if the PC level was large, the interior noise was increased by the vibration characteristic. On the other side, if the PC transfer function was large, the noise was increased by the acoustic characteristic (resonance) in cabin. According to the above consideration, we actually applied a countermeasure to change the resonance frequency in cabin because the PC transfer function increased the interior noise. As the result, the interior noise at the target frequency could be decreased very well.