Structural health monitoring (SHM) for complex structures is highly practical in engineering field. Channel-like aluminium alloy structures were evaluated in terms of both finite element method (FEM) and experiment-based Lamb wave analysis for the purpose of damage detection. Three-dimensional FEM models were established to simulate the propagation behavior of Lamb wave in the structures. In experiments, piezoelectric lead zirconate titanate (PZT) wafers were employed to generate Lamb waves propagating in the structures as actuators and to collect Lamb wave signals as sensors. Taking advantages of continuous wavelet transformation (CWT) and Hilbert transformation (HT), the time domain features of the collected Lamb wave signals, the time-of-flight (ToF) of the crack scattered wave component, were extracted. The quantitative relationship between the crack location and the ToFs was established consequently:%研究复杂工程结构的结构健康监测技术具有现实意义.使用基于Lamb波的仿真和实验方法,对“U”形截面的铝合金构件中的损伤检测问题进行了研究.建立了构件的三维有限元模型并实现了Lamb波传播过程的动态仿真；实验中使用锆钛酸铅压电晶片(PZT wafer)来激发和接收在构件中传播的Lamb波.借助于连续小波变换(CWT)和希尔伯特变换(HT)等方法对仿真和实验中采集到的Lamb波信号进行处理,从中提取了与损伤有关的时域特征,建立了损伤位置和损伤反射波包飞行时间(ToF)之间的定量关系.
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