中文摘要：

非线性Lamb波监测技术是结构健康监测研究的热点之一。为了解决线性Lamb波监测结构早期微损伤敏感度低的问题,采用具有积累效应的（S1,S2）对称模式非线性Lamb波方法,实现对金属结构材料非线性变化的定量监测。实验结果表明,非线性Lamb波信号及特征参数对结构材料非线性变化十分敏感,且随模拟疲劳损伤范围的扩大,特征参数呈线性增长,而基频信号的变化很微弱,从而验证了非线性Lamb波方法对疲劳等结构早期损伤监测的有效性和可行性。

英文摘要：

The nonlinear Lamb wave monitoring technology is one of the hot topics in the structural health monitoring.To solve the low sensitivity problem in the early micro damage of linear Lamb wave monitoring structure,this article adopts the symmetric mode（S1,S2）nonlinear Lamb wave which has a cumulative effect to achieve quantitative monitoring of metallic structural material nonlinear changes.The results show that the nonlinear Lamb wave signals and characteristic parameters are sensitive to structural material nonlinearity change.With the increasing of simulative fatigue damage scope expanding,the characteristic parameter grows linearly,but the change of fundamental frequency signal is weak.The results validated the feasibility and effectiveness of the nonlinear Lamb wave method to early structure fatigue damage monitoring.