This paper deals with the characterization of multi-layer actuators and bulk PZT ceramics under the influence of an applied electric field. The displacement profile of materials and devices with evaporated reflective dielectric layers was measured using a double-beam laser interferometer at room temperature. The displacements of 3 mm thick plates of bulk soft PZT were characterized to determine bulk material properties. The tested multi-layer actuator devices consisted of 20 layers, with each layer being 87 micrometers thick. The results of "point to point scanning" of displacement across piezoelectric materials are presented and the effective actuation area of the actuator displacement is determined. Comparisons are made of the behaviour of the bulk ceramics and the actuator In addition to experimental measurement, representative coupled-field finite element model was constructed to compare with experimental x - y displacement data of multi-layer actuator.
Burianova, L., Bowen, C. R., Prokopova, M., & Sulc, M. (2005). Laser interferometric displacement measurements of multi-layer actuators and PZT ceramics. Ferroelectrics, 320, 629-637. https://doi.org/10.1080/00150190590967026