Research on multi-band structural noise reduction of vehicle body based on two-degree-of-freedom locally resonant phononic crystal

Abstract

First, the dispersion curve of a two-degree-of-freedom locally resonant phononic crystal (LRPC) is calculated by the plane wave expansion method. The result shows that the structure has the characteristics of double bandgaps in the mid- and low-frequency range, which is verified by the finite element method. Then, the frequency response analysis of the interior noise and the acoustic contribution analysis of car panels are carried out, and the front left floor is found out to be the panel with a larger contribution of the peak value of noise. Therefore, the LRPC is arranged on the front left floor based on the modal strain energy, and then the total vibration level and the radiated sound power level of the panel are calculated, which are both decreased by 11 dB to 13 dB after the arrangement of LRPC. The acoustic simulation analysis of the whole vehicle after the arrangement is also carried out, which shows that the original sound pressure level peaks at 270 Hz, 346 Hz and 378 Hz are reduced by 6.2 dB(A), 5.56 dB(A) and 9.35 dB(A), respectively. The results provide guidance for the application of LRPC in the field of structural noise reduction of engineering plates.