中文摘要：

基于非线性Lamb波信号的损伤监测研究是近几年发展起来的热点。受频散及多模特性的影响,非线性Lamb波目标模式信号的分析和提取较难。采用时频处理法,结合频散曲线,研究了主动Lamb波结构损伤监测中的非线性信号提取法,并进行了实验验证。实验结果表明,该方法可有效分辨和提取出期望的基频和非线性二倍频模式信号,进一步模拟损伤实验验证了非线性特征信号对结构状态变化的敏感性。

英文摘要：

The nonlinear Lamb wave based damage detection method has become a focus recently. However, the extraction and process on expected mode signal were usually difficult due to the dispersive and multi mode characters of Lamb wave. Time-frequency process technique and dispersive curves were adopted to develop the extraction method of nonlinear Lamb wave in active damage monitoring which was also validated experimentally. The results indcate that the developed method could distinguish and extract the expected modes effectively. Further simulated damage monitoring experiments validated that nonlinear characteristic signals were sensitive to the structural variation.