利用Lamb波的薄板结构多点损伤识别试验

Experimental Research on Multi-Damage Detection of Metal Plate Structure Using Lamb Wave

目的提出一种改进的小波-椭圆损伤定位算法,利用该算法进行薄板结构的多点损伤识别.方法利用Lamb波在薄板结构中的传播特性,将粘贴在铝板表面的压电陶瓷片作为驱动器和传感器,在铝板结构中激发出Lamb波并实时接收响应信号.通过人工模拟铝板中的孔洞类缺陷,对采集到的损伤前后波形进行对比.结果得到了Lamb波的传播速度、响应信号的小波变换结果以及损伤前后信号的到达时间延迟.还得出了损伤位置的试验值,与实际损伤位置吻合较好.结论 Lamb波主动监测技术可以有效地识别薄板结构的损伤,适合于薄板金属结构的损伤识别和健康监测.

This paper presents a new method for multi-damage detection of metal plate structure by using a wavelet relevant and elliptic line method. Using the Lamb wave propagation characters in the plate structure, the PZT patches are adhered on the surface of an aluminum plate structure to be used as actuators and sensors,Lamb waves are emitted and received by the PZT patches to detect damage in the structure. By the experiment of artificial holes, which are used to simulate the damages in the plate structure using active Lamb waves, the prototype and damaged signals are compared to set up an index for the damage detection. This paper obtains the propagation velocity of Lamb wave, the wavelet transformation results and the arrival time delay of sensing signals before and after damage, also the damage positions in the experiment are received, and they accord well with the actual damage positions. Active Lamb wave monitoring technology can effectively identify damage of plate structure, therefore, it is suitable for damage identification and health monitoring of sheet metal structure.