Integration and Design of Piezoelectric Patch Actuators

The design of induced strain actuators is a comprehensive issue, involving not only the materials and geometry of the actuators, but also the behaviors of the coupled host structures. In particular, the design of the actuators is essentially related to the prediction of induced strain or stress. A high stress or strain level in the actuators is useful to excite host structures; however, degradation or fatigue damage of the actuators may take place at the same time. This paper presents a dynamic analytical approach for the design of piezoelectric (PZT) patch actuators locally coupled with host structures. Several critical design issues are addressed. These issues include the determination of actuator dynamic outputs, the prediction of energy conversion efficiency, the estimation of system power requirement, and the limitation of induced alternate peak stress. A coupled electromechanical analytical model was developed to reveal the inherent connections among these issues. The mechanical stress behavior of PZT patch actuators was investigated. The attention in parametric design was directed to the thickness and location of the actuators. A simply-supported thin plate with surface-bonded PZT patches was built and tested to directly measure the induced dynamic strain of the PZT actuator so that the prediction accuracy and ability of the design model could be validated.