Characterization of mode selective actuator and sensor systems for Lamb wave excitation

Structural Health Monitoring (SHM) based on Lamb waves, a type of ultrasonic guided waves, is a promising technique for in-service inspection of composite structures. This study presents the development of mode selective actuator and sensor systems based on interdigital transducer (IDT) design. Various parameters such as wavelengths, number and apodization of electrodes as well as eigenfrequencies of the transducer are characterized. Therefore, an analytical model based on the theory of surface acoustic wave (SAW) filters is investigated in order to evaluate the acoustic response of the transducer. Furthermore, experimental tests on composite plates are performed.