PIEZO2021

Ultrasonic guided waves (UGW) are now common in many Structural Health Monitoring (SHM) systems as they can be senses and generated with piezoelectric devices. The paper will review the state of the art of the current piezoelectric devices based on piezoceramic/piezocomposite materials employed for SHM and the emerging devices based on piezopolymer films. The dispersion behavior of UGWs in laminate structural materials (metallic or composite fibers reinforced composite) suggests the selection of specific propagation modes to alleviate the burden of signal interpretation and the patterned comb electrodes configuration is one of the most promising solution, well known as Interdigital Transducers (IDT). The IDTs can be designed with the finger electrodes geometry to select the Lamb wave mode of interests. The dimensions and geometry of the fingers are related to the transducers characteristics as frequency response, sensitivity, directivity. The fabrication of IDT for the 50 kHz – 1MHz frequency range based on of piezoelectric film is of interest for the flexibility and the compliance to the target surface structure.