Transfer Path Analysis and Low-Frequency Vibration Reduction by Locally Resonant Phononic Crystal 2019-01-0786
The vibration characteristics of the motor on electric vehicles are different from those of internal combustion engine because it exhibits order and multi-band characteristics in the frequency domain. This property makes the phononic crystals with forbidden bandgap an ideal solution to eliminate the vibration transmission of the motor because the concentrated vibration peak can easily be blocked by the bandgap. In this paper, one dimensional locally resonant phononic crystals (LRPCs) which have low-frequency bandgaps are arranged on the automotive subframe to absorbing vibration. The partial coherence analysis is used to analyze the transfer characteristic of vibration on the subframe. Then, 6 main paths are selected from the 18 vibration transmission paths, and the arrangement of the LRPCs are chosen based on this result. An experiment of a one-dimensional LRPC beam was used to calculate the transfer function. The results show that the theoretical calculation, finite element simulation, and experimental bandgap are consistent. Finally, the transfer functions of the subframe are calculated by the finite element method. By comparing the two cases whether with or without LRPCs, the results show that after optimization, better vibration attenuation can be achieved under the premise of small mass increase. This result provides a new method for low-frequency vibration reduction of electric vehicles.