基于二次谐波的对称波纹板早期损伤检测

The material early-stage damage evaluation of the symmetrical undulated plate based on the second harmonic

为方便利用非线性兰姆波二次谐波分量进行对称波纹板的早期损伤无损健康检测,基于二次材料弱非线性,建立非线性兰姆波二次谐波结构准相位匹配理论。以结构准相位匹配理论为指导,依据波纹板的空间周期和平均厚度,选择超声波检测基波频率,确定接收探头的空间分布规律。以经过汉宁窗调制的中心频率为500 kHz的短脉冲激励为例,建立仿真模型,验证对称波纹板结构准相位匹配理论,实施对称波纹板材结构早期损伤超声无损健康检测。理论仿真结果与分析讨论表明,通过结构准相位匹配,对称波纹板非线性兰姆波二次谐波分量具有更长的累积距离,可从基波获得更多的能量,可有效实施基于非线性兰姆波二次谐波分量的波纹板结构早期损伤超声无损健康检测。

For the convenience of using the second harmonic component of the nonlinear Lamb wave to monitor the material early-stage damage of the symmetrical undulated plate,based on the quadratic weak material nonlinearity,the structure quasi-phase-matching theory of the second harmonic component is established.The frequency of the fundamental wave and the space distribution of the detection transducers are obtained based on the structure quasi-phase-matching theory.A simulation model is established.A Hanning windowed tone burst signal with center frequency of 500 kHz is adopted as the excitation signal.The structure quasi-phase-matching theory is verified by the simulation and the material early-stage damage of the undulated plate is evaluated.Theoretical results simulation results and discussion analysis show that longer accumulation distance,more energy capturing of the nonlinear Lamb wave second harmonic component and the monitoring of the material early-stage damage of the undulated plate based on the second harmonic can be achieved by structure quasi-phase-matching.