复合材料层合板损伤的延迟累加成像算法

Delay and Sum Damage Imaging Algorithm of Laminates Composite Panel

由于复合材料结构的各向异性,导致难以准确获得导波的波速和传播时间。因此在使用传统的延迟累加成像算法对复合材料结构进行损伤识别过程中,会造成损伤定位精度的降低。考虑到复合材料的各向异性导致导波在各个方向的波速并不相同,提出了一种改进的延迟累加损伤成像算法。该方法通过利用激励器与成像点以及成像点与传感器之间的方向角,在成像过程中选取了不同的方向波速进行损伤识别。通过一复合材料层合板冲击损伤的监测实验,将所提算法与采用不同方向波速的传统延迟累加成像算法进行对比,对所提方法的有效性进行了验证。实验结果表明:相比于采用单一速度的延迟累加成像算法,该方法的损伤监测误差控制在4%以内。

Due to the anisotropy of composites structures,the accurate wave velocity and time of flight of ultrasonic guided waves were hard to acquired. As a result,the traditional delay-and-sum imaging algorithm was used to identify the damage of composites structures,which reduced the damage localization accuracy. Considering different wave velocity in different direction result of the anisotropy of composites structures,an improved imaging algorithm was proposed. Using the different direction angles from the actuator to the imaging point and from the imaging point to the sensor,the different wave velocity was applied to identify the damage. The validity of the proposed algorithm was assessed by identify the impact damage of laminates composites panel. The results show that the monitoring error of the improved algorithm is below 4%,comparing with the traditional delay-and-sum imaging algorithm using single wave velocity.