Vibration Analysis for a 12-DOF Full Car Model with Hydraulic Engine Mounts of Frequency Dependent Stiffness and Damping

摘要

Hydraulic mounts have been applied underneath power train of vehicle to achieve better ride comfort. A lumped mass-spring-dashpot (MCK) model was often used to model the hydraulic mount in vibration analyses of vehicle in the previous studies. But, it was found that modeling the hydraulic mount as the lumped mass-spring-dashpot model can be justified only when the bottom of the hydraulic mount is fixed. In this study, transfer function model for the hydraulic mount derived based on hydraulic dynamics will be adapted and compared with the lumped mass-spring-dashpot model through vibration analyses of 4 and 12-degrees of freedom (DOF) vehicle model. Furthermore, it will be shown that the highly frequency dependent stiffness and damping characteristics of the hydraulic mounts generate extra vibration modes unexpectedly in rather high frequency ranges theoretically, which have never been treated in the previous literatures. Then, the significance of the extra vibration modes by the dynamic characteristics of hydraulic mounts in vehicle model will be discussed as well. Finally, this study is expected to be used to understanding the vibration characteristics of vehicle, which contains the hydraulic engine mount.