A Study on Natural Frequency Characteristic of the Side Member as a Vibration Transfer Path of the Vehicle

When a vehicle driving, excitation forces of the powertrain with wide frequency range are transmitted through structure transfer paths, likewise powertrain support brackets, mounts and side member frame. Some vibration response levels caused by the dynamic characteristics of the transfer path system are amplified during the dynamic operating situation. Sometime, an unintended NVH problem could be occurred because when the natural frequencies of the transfer path elements, likewise powertrain support brackets, mounts and side member frame are overlapped. Therefore, it is need to identify those natural frequency characteristics and try to avoid its overlap in advance. In this paper, some overlapped natural frequency cases of the transfer paths are studied. By analysing and studying the natural frequencies and stiffness level of the transfer path item, likewise transmission support bracket, mount and side member frame, a correlation between the test and analysis is achieved up to 1 kHz in the vehicle. As a result, with respect to this method in early design stage, new transfer path NVH analysis process is proposed and built.