' Quantitative Modeling of Dynamic Behavior of a Piezoelectric Wafer Actuator bonded to an Elastic Plate for Guided Wave Propagation

Piezoelectric wafer actuators (piezo-actuators) have been extensively used in integrated structural health monitoring systems to generate ultrasonic guided waves (GWs) for structural damage interrogation. The big issue surrounding precise characterization of piezoelectrically excited GWs is addressing the dynamic interfacial stress between the piezo-actuator and the host structure. In this paper, an analytical actuator model is developed to quantitatively describe the dynamic load transfer between a bonded thin piezo-actuator and an isotropic plate under in-plane mechanical and electrical loading. The piezoelectrically induced GW responses are studied by coupling the actuator dynamics with the Rayleigh-Lamb equations and solving the resulting integral equations in terms of the interfacial shear stress. Typical examples are provided to show the capability of the current actuator model to capture the effects of the geometry and the loading frequency upon the load transfer. The analytical prediction of transient GW mode signals from the proposed model is compared with finite element simulation results for various excitation frequencies, and excellent agreement can be observed especially for high-frequency cases, which is a useful extension to the ultrasonic frequencies of most of existing analytical solutions for low frequency approximations.