<title>Experimental investigation on the effect of environmental stress on active fiber composite actuators</title>

Abstract

Active Fiber Composite (AFC) actuators comprise piezoelectric fibers, polymer matrix, and interdigital electrodes. They are conformable, robust and have higher strain actuation than standard in-plane PZT actuators due to the 33 mode of actuation offered by interdigital electrodes. Taking advantage of the 33 actuation necessitates the alignment of the poling axis and load path axis. Piezoelectric material are more vulnerable to stress induced depolarization when the loading and poling axes are aligned than when they are transverse. The poled PZT fibers will remain poled as long as they are under sufficiently low mechanical, thermal, and electric fields. Extreme values of any of these environments will cause depolarization, resulting in substantially reduced actuation. The compressive stress levels along the poling axis required to depole bulk PZT-5A piezoceramic samples under low field excitation are well documented. An AFC is a more complicated system, however, and the compressive stress levels which cause depolarization are not necessarily the same as for bulk piezoceramics. This paper describes a set of experiments designed to determine the compressive stress induced depolarization limits of AFC actuators with PZT-5A fibers. Results indicate that the AFCs are much more robust to compressive stress induced depolarization than is suggested by data published on bulk piezoceramics.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.