Lamb波波包混叠分离方法的结构损伤定位

Structural Damage Localization Based on Lamb Wave Packet Aliasing Separation Method

基于Lamb波信号延时累加的结构损伤成像方法具有结果准确、计算量小等优点,然而在复杂的航空结构中,Lamb波非常容易产生反射,由于Lamb波频散效应,导致多个波包混叠,从而影响定位的准确性。针对这些问题,提出了一种频散波包的分离补偿方法。首先,理论分析并得到了带有频散效应的波包混叠和函数模型,提出了和函数的隐变量参数求解方法;其次,采用数值仿真验证了算法对于波包分离和重构的有效性;最后,通过飞机复合材料加筋壁板的损伤定位实验验证了波包分离法在复杂边界条件下去除反射波伪损伤投影和频散补偿的能力,提升了损伤定位的准确度和成像的分辨率。

The delay-and-sum structural damage imaging method based on Lamb wave has the advantages of accurate result and low computation cost. However,in complex aeronautical structures,Lamb waves are very prone to reflections because of the complexity of boundary conditions,especially in case of multiple damages.Due to the Lamb wave dispersion effect,multiple wave packets are aliased to affect the positioning results. In response to these problems,this paper proposes a separation and compensation method for dispersion wave packet. Firstly,the aliasing wave packet function considering dispersion effect is theoretically obtained,and the method for solving the sum function is proposed based on hidden variables. Then numerical simulations are used to verify the effectiveness of the algorithm for wave packet separation and reconstruction. Finally,the damage localization experiment of the composite stiffened panel is carried out to demonstrate the capacity of the proposed method. Experimental results prove that it can remove the pseudo-damage projection of the reflected wave under complex boundary conditions,thus improving the accuracy of the damage positioning and the resolution of the image.