Lamb波结构损伤检测温度补偿方法仿真与实验研究

Experiment and simulation of compensation for temperature influence on Lamb wave propagation for damage detection

基于压电激励Lamb波传播过程分析研究了信号扩展时域温度补偿方法,分别进行了不同温度下Lamb波传播与损伤检测的有限元数值仿真和实验,利用基准信号选择和基准信号扩展的温度补偿方法处理波动响应信号。仿真和实验结果表明了温度补偿方法的有效性,得到了基准信号集中最大温度间隔要求,能够有效识别环境温度变化下的结构损伤。

Among structural health monitoring （SHM） techniques, Lamb waves are frequently used as diagnostic tools to detect damage in plate-like structures. Temperature variation can cause significant changes in guided-wave propagation and transduc- tion for SHM. It is most important to compensate the temperature variation for those methods in which the present signals should be compared with the baseline ones in order to detect the structure damage. In this paper, a transient dynamic finite ele- ment simulation of Lamb wave for damage detection in a stiffened plate under different temperature conditions is carried out on the commercial finite element code ANSYS platform. Simulations are conducted over a temperature range of 25~75 ~C using 275 kHz as excitation frequencies. The changes in temperature-dependent material properties are used to measure the differ- ences in the waveform o~ the response signal. Then controlled experiments examine changes in Lamb wave propagation and transduction using PZT-SA piezoelectric wafers under quasi statically varying temperature （from 5 ~C to 60 ~C）. The baseline selection method and baseline signal stretch method are used to compensate the temperature influence on Lamb wave propaga- tion. The results of the numerical simulation and experiments demonstrate the effectiveness of the temperature compensation approach. The requirement of maximum temperature interval for baseline signal set is obtained, thus the simulated damage on the aluminum plate can be detected effectively under varying temperature environment.