PVDF梳状换能器接收非线性兰姆波的实验研究

Receiving nonlinear Lamb waves using PVDF comb transducer

该文基于PVDF压电薄膜对梳状换能器进行设计制作,并将该换能器应用于接收非线性兰姆波信号实验研究.首先通过输出矢量和方法分析PVDF梳状换能器的工作特性,然后将设计制作的PVDF梳状换能器应用于铝板中非线性兰姆波信号的接收,并与传统压电陶瓷换能器经斜劈接收的非线性兰姆波信号进行比较分析.实验结果表明,两种换能器所接收到的信号幅值随传播距离的变化趋势相近,线性增长的积累效应表征结果相似,且PVDF梳状换能器可以对基波和二次谐波信号同时响应.除此之外,PVDF梳状换能器用于接收非线性兰姆波信号更加稳定.因此,PVDF梳状换能器有望应用于复杂构件的在线检测与监测研究.

In this paper, the comb transducer is designed based on PVDF piezoelectric film, and the transducer is applied to the experimental study of receiving nonlinear Lamb wave signals. Firstly, the harmonic-frequency characteristic of PVDF comb transducer are analyzed by output-vector addition method. Then, the designed PVDF comb transducer is applied to the reception of the Lamb wave nonlinear harmonic signal in the aluminum plate, and compared the result with the nonlinear Lamb wave signal received by the traditional piezoelectric ceramic transducer through the oblique beam. The experimental results show that the changing tendencies of amplitude under different propagating distances achieved by two transducers are similar to each other. The PVDF comb transducer can respond to both the fundamental and second harmonic signals. In addition, PVDF comb transducers are more stable for receiving nonlinear Lamb wave signals. Therefore, PVDF comb transducers are expected to be applied to online detection and monitoring of complex components.