Integration and Design of Piezoceramic Elements in Intelligent Structures

Abstract

The design of induced strain elements (actuators) is a comprehensive issue, involving not only the materials and geometry of the elements, but also the behaviors of the coupled host structures. In particular, the design of the active elements is essentially related to the prediction of induced strain or stress in the elements. 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 and integration of active piezoceramic (PZT) patch elements locally coupled with host structures. Several critical design issues are addressed. These issues include the determination of the 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 electro-mechanical analytical model was developed to reveal the inherent connections among these issues. Both the mechanical stress behavior and the thermal stress characteristics of the PZT patch elements were investigated. A system power consumption-based model was developed to estimate the temperature and thermal stress distribution of the elements. The attention in parametric design was directed to the thickness and location of the elements. A simply-supported thin plate with surface-bonded PZT patches was built and tested to directly measure the induced dynamic strain of the PZT element so that the prediction accuracy and ability of the design model has been validated.