<title>Durability properties of piezoelectric stack actuators under combined electromechanical loading</title>

Abstract

This paper presents result on electro-thermo-mechanical behavior of piezoelectric materials for use in actuator applications with an emphasis on durability performance. The objective of this study was to compare the performance of different commercially available actuator systems and to determine the properties necessary for design of such actuator systems. Basic piezoelectric properties of five stack actuators were determined as a function of mechanical preload and temperature. Changes in these properties during ferroelectric fatigue up to 107 cycles were determined from strain-field relations after specified number of fatigue cycles. Experimental results indicate strong dependence of piezoelectric properties and power requirements on mechanical loading conditions. Results indicate that the optimum operating conditions can be determined that will improve actuation capabilities of piezoelectric stack actuators. That is, strain output was found to increase by 60 percent for some actuators upon the application of certain compressive prestress. Results of fatigue tests indicate negligible degradation in strain output for some stack actuators even when operated under mechanical preload that cause large displacements through domain wall motion. Similar trends in strain output and current degradation curves suggest that material degradation can be indirectly inferred from simply measuring the current being dissipated by the material. Finally, temperature rise of PZT stacks due to self-heating into account when designing actuator systems, since temperature changes were found to significantly influence both strain output and power required to drive piezoelectric stack actuators.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.