基于同心压电传感器的单模态Lamb波信号提取方法

Lamb波具有传播范围远、对小损伤敏感等优点,适用于飞机机翼、壁板等大面积结构的损伤检测,然而Lamb波的频散和多模态特性使得单模态难以识别和解析信号。本文提出一种适用于板壳结构损伤检测的单模态提取方法,设计并使用一种同心压电传感器,根据所激励各模态的幅值比来分解信号并补偿时间差,从而提取出单一模态的信号。通过仿真分析和铝板实验验证,结果显示本方法能够有效提取单一A0模态信号,并在实验中成功识别了隐藏的裂纹损伤反射回波信号,使信号相对于传统方法变得更易解释和分析。

Single mode signal extraction method of Lamb wave using a concentric PZT transducer

Lamb waves-based damage detection method is able to identify defects effectively for large area structures such as airplane wings and panels with the advantages of large area scanning and good sensitivity to minute defects. However, due to the dispersive and multimodal natures of Lamb waves, it is difficult to interpret and analyze the single mode signals, resulting in negative effect on damage detection. To solve this problem, a single mode signal extraction method of Lamb waves for damage detection is proposed in this paper. A concentric PZT transducer is designed and applied. The single mode signals can be extracted based on the time-shift compensation and the amplitude ratio of multi-mode signals excited by the concentric PZT. Through numerical simulation and experimental tests performed on an aluminum plate, the results validate the effectiveness of the proposed technique. The hidden scatter defect signals are also successfully extracted in experimental tests. This technique has the potential to expand the envelope of data analysis beyond the conventional limitations.