As electric motors in electric vehicles generate more sever vibration excitation in high frequency range (up to 3 kHz), a low dynamic hardening mount is needed. The dynamic stiffness of mounts increase significantly with the increase of excitation frequency and will have several peak values, which are known as internal resonances. In addition, the driving- and cross-point dynamic stiffness deviate in high frequency range. To investigate the issue of high frequency vibration isolation, a modeling approach to describe the high frequency dynamic stiffness of motor mounts is proposed. Secondly, the concept of double-isolation mount consisting of two mount and one additional mass is presented. Then, the force transmissibility of single degree of freedom system including a motor and a mount is represented as the vibration isolation effectiveness. Simulation results show that the single degree of freedom with the double-isolation mount exhibits better vibration isolation in high frequency range.
 

Vibration,high frequency,dynamic stiffness,mount