基于声压测量的结构模态参数辨识

Identification of structural modal parameters based on sound pressure measurement

通过建立辐射声压与激振力之间的声压频响函数矩阵,提出了一个基于测量声压识别振动结构模态参数的方法。该方法可以通过非接触测量声压来识别结构的固有频率、模态阻尼比与模态振型,避免了附加质量对结构的影响。声压频响函数矩阵是基于边界元和Rayleigh积分方法结合有限元结构动力学方程建立的,适用于任意结构且与结构模态参数有明确的关系;对于测量声压时多激励单输出与单激励多输出响应的不同试验模式,该方法都能识别结构的模态参数。以一平板结构为例,数值验证了该方法的准确性与适用性。

Based on the frequency response function of sound pressure,a method of identifying structural modal parameters from measured sound pressure was proposed. It can accurately identify the structural natural frequencies,damping ratios and mode shapes from the measured sound pressure,and can avoid mass loading due to the use of vibration sensors on the structure in traditional measurements. Combined with structural dynamic equations,the sound pressure frequency response function was established based on the boundary element method and the Rayleigh integral formulation for sound radiation from an arbitrary body. The method was also able to identify the structural modal parameters with Single-Input-Multiple-Output testing and Multiple-Input-Single-Output testing. Finally the accuracy and the validity of the method were verified through numerical simulations.