基于Lamb波无基准方法的裂纹检测

传统的结构健康监测技术容易受到温度、振动噪音等与结构缺陷无关的因素影响.为了克服这一缺陷,发展了一种基于传递阻抗的无基准裂纹检测方法.该方法既不需要基准数据,也不需要损伤阈值,而是利用裂纹导致的Lamb波模式转换效应和PZT极化特性从两组并排的PZT元件间获取传递阻抗,通过比较传递阻抗的能量来判断裂纹是否存在.仿真和实验表明,该方法无需选择最优的激励频率和采样时间即可实现对裂纹的检测,具有较强的鲁棒性和适用性.

Reference-free Lamb wave crack detection based on transfer impedance energy

Traditional structural health monitoring (SHM) techniques are vulnerable to factors such as temperature change and vibration noise that are unrelated to the structural defects. To overcome this drawback, a reference-free Lamb wave crack detection method based on transfer impedance energy was developed. Neither reference data nor damage threshold was required in this method. According to the crack-lead Lamb wave mode conversion effects and PZT polarization characteristics, transfer impedance was got from PZT elements of two sets of side-by-side. Whether there been a crack was determined by comparing transfer impedance energy of each feature signals. Simulation and experiments show that the proposed method has strong robustness and applicability, as it was not sensitive to the optimal excitation frequency and the sampling time of signals.