基于PVDF梳状换能器的零群速度Lamb波层合板损伤检测的数值研究

Numerical investigation on damage detection of ZGV Lamb waves in laminated plates based on PVDF comb transducers

为提高层合板损伤检测的准确性与灵敏度,基于聚偏二氟乙烯(polyvinylidene fluoride,PVDF)梳状换能器激发的零群速度(zero group velocity,ZGV)Lamb波,提出了一种层合板损伤的检测方法。采用二维时域有限元方法,研究了PVDF梳状换能器对零群速度Lamb波的激励,通过改变层合板中铝层杨氏模量来表征不同的损伤程度,分析了PVDF梳状换能器电压响应特性与层合板损伤程度之间的关系。结果表明:采用PVDF梳状换能器能够有效激励零群速度Lamb波,并获得层合板内部的状态信息。随着损伤程度的增加,PVDF梳状换能器响应的零群速度共振峰频域幅值随着铝层杨氏模量的减小而显著减少,进而灵敏地评价层合板损伤变化。研究结果说明优化设计的PVDF梳状换能器在零群速度Lamb波的激发与接收性能上都具有优越性,能够有效检测层合板损伤情况。

In order to improve the accuracy and sensitivity of damage detection in laminated plates,a damage detection method is proposed based on zero group velocity(ZGV)Lamb waves excited by polyvinylidene fluoride(PVDF)comb transducers.The two dimensional time domain finite element method is used to study the excitation of the ZGV Lamb waves by PVDF comb transducers.By changing Young's modulus of the aluminum layer in laminated plates to characterize different damaged degrees,the relationship between the voltage response characteristics of PVDF comb transducers and the damage degree is analyzed.The results show that PVDF comb transducers can effectively excite the ZGV Lamb waves and detect the damaged degree of laminated plates.As the damage degree increases,the ZGV resonance peak amplitude response by the PVDF comb transducers in the frequency domain decreases significantly with decreasing Young's modulus of the aluminum layer,so as to evaluate the change of damage in the laminated plates sensitively.The optimized PVDF comb transducers have advantages in the excitation and reception performance of ZGV Lamb waves,which further improves the accuracy and sensitivity of damage detection in laminated plates.