板结构的声辐射模态分析及其高分辨率法向振动速度重建

Acoustic radiation modes analysis and high resolution reconstruction of normal vibration velocity on plate structures

提出了一种基于声辐射模态的速度基向量构建方法,该速度基向量不受网格划分的影响,可用于高分辨率的板结构法向振动速度重建。首先对板表面稀疏网格的声辐射模态进行计算,再以声辐射模态和模态系数构建板法向振动速度分布的基向量,然后由声场测量声压求解基向量系数,最后由该系数和加密网格的速度基向量重建高分辨率的板法向振动速度分布。以简支板声源进行仿真计算,当测量声压信噪比为30 dB时,低频的法向振动速度重建误差最低可达3.7%;以固支板声源在消声室中进行实验验证,131.5 Hz振动频率下的重建误差低于7%。该方法实现了只需要少量声压测量点即可精确重建板声源更高分辨率的法向振动速度分布。

A method was proposed to construct velocity basis vectors with acoustic radiation modes,and the vectors won’t be affected by the grids distribution,thus it can be applied to high resolution reconstruction of the normal velocity on a plate.Firstly,the acoustic radiation modes of the plate with sparse grids are calculated,and then the basis vectors are constructed with the acoustic radiation modes and the corresponding mode coefficients,afterwards the weights of basis vectors are solved with measured sound pressure in the sound field.Lastly,the normal velocity on the plate is reconstructed from the weights and another series of basis vectors of dense grids.The numerical simulation was calculated with sound source of a simple supported plate.When the SNR of measured sound pressure was 30 dB,the smallest reconstruction error of the normal velocity reached to 3.7%at low frequency.The experimental verification was implemented with a clamped plate in an anechoic chamber,and the reconstruction error was less than 7%at frequency 131.5 Hz.The method proposed realized that the normal velocity distribution on a plate can be reconstructed with higher resolution with only fewer sound pressure measurements.