A Monolithic Interdigitated PVDF Transducer for Lamb Wave Inspection

A monolithic interdigitated PVDF transducer (PVDF IDT) was built in this study. This PVDF IDT is capable of generating and receiving Lamb waves for structural health monitoring. Unlike most existing laminate-structured interdigitated PVDF transducers, this PVDF IDT features a monolithic structure, which eliminates sensor delamination as a potential problem. The flexible nature of PVDF promises the ability for the sensor to be attached to different structural surfaces. Other advantages of this PVDF IDT include low unit cost, easy installation, low power consumption, and the ability for wireless operation or remote interrogation. The fabrication of this sensor was accomplished by using etch-back photolithography technology. The interpretation of the complex Lamb wave signals was realized by using the continuous wavelet transform (CWT).