Lamb波时间反转分解损伤识别方法研究

TIME REVERSAL DECOMPOSITION BASED LAMB WAVE DAMAGE DETECTION METHOD

基于主动Lamb波的结构健康监测和损伤检测是目前研究的热点之一。时间反转分解方法利用发射-接收阵列可以选择性地分别聚焦定位各个散射体.由于Lamb波传播的频散和多模式特性,导致了Lamb波时间反转传递矩阵的不对称性。基于压电激励Lamb波传播过程,分析研究了Lamb波时间反转传递矩阵显著特征值数目与散射体数目的关系,进行了Lamb波传播与损伤检测的实验研究,利用Lamb波A0和S0模式传播解析解数值反向传播,定位板中各个散射体。实验结果表明了Lamb波时间反转分解损伤识别方法的有效性,能够有效识别并定位结构损伤。

This work presents the development of a technique for multiple-damage detection based on the Lamb wave decomposition of the time reversal （DORT） method. An experiment is carried out to distinguish and locate two simulated damages on an aluminum plate. The behavior of reflected muhimode waves is analyzed by studying the eigenvalues and eigenvectors of the time reversal operator matrix. The number of significant eigenvalues is not exactly the number of damage targets and two significant eigenvalues are associated to one damage target. The results show that the DORT method can estimate the position of the damaged zones in 2D image by numerically backpropagating selective eigenvector using the S0 and/or A0 Lamb wave propagation analytical solution.