Properties of Interdigital Transducers for Lamb-Wave Based SHM Systems

ABSTRACT 1 Recently, an intensive research activity has been observed concerning the application of guided waves to long range ultrasound (LRUT) and structural health monitoring. Guided waves propagating in plates, known as Lamb waves, have appeared to be suitable for monitoring and condition evaluation of planar structures. Lamb waves can be generated using different types of actuators including piezoelectric or electromagnetic acoustic transducers. In this paper a novel type of piezoelectric transducers is presented based on macro-fiber piezocomposite (MFC). Contrary to the previously presented MFC transducers the transducers presented here are provided with interdigital electrodes matched to certain wavelength. Two different designs of interdigital transducers (IDT) made of MFC substrate are presented in the paper together with the results of numerical simulations and experimental tests.