Booming noise 개선을 위한 차체 Panel의 Bead 형상 최적화에 관한 연구

Structure borne noise is one of the major Noise/Vibration performance issues, which is caused by excitations from engine and road. This noise is perceived by passengers very often because it has broad bandwidth of driving situation from idle to high speed. The root cause of this noise is known to be related to coupling of panel vibration and cavity resonance, which is driving pressure change measured specially at ear location of passenger. In order to de-couple the frequency of panel and cavity resonance, it’s necessary to identify the noise transfer path and related frequency range. It was possible to identify each panel’s contribution rate, by inner product calculation of each panel’s vibration vectors. Even though the noise transfer path, main contribution panels and target frequency range are identified, it’s necessary to do work more on mass reduction as much as possible. In this study, there are not much design freedom lefts for changing large panels, and we tried to pursue local solutions. Mid reinforcement panel was chosen to modify and put into bead shape optimization program using Topography approach. The optimal solution was successfully extracted and the performance improvement was confirmed.