Analytical and experimental study of nonlinear bending response and domain wall motion in piezoelectric laminated actuators under ac electric fields

We investigate the nonlinear bending behavior of piezoelectric laminated actuators as a function of the amplitude and frequency of large electric fields both analytically and experimentally. Laminated beam theory is expanded to allow for the cantilever piezoelectric/metal/piezoelectric actuator, and the effects of alternating current (ac) electric fields on the tip deflection are analyzed. A simple phenomenological model of a vibrating domain wall in electric fields is used, and the macroscopic actuator response is predicted. A nonlinear three-dimensional finite element analysis is also employed. Experimental results are presented to validate the predictions using bimorph-type bending actuators made with thin soft lead zirconate titanate (PZT) layers and a thin metal sheet. Calculations show reasonable agreement with the experimental data, and support a role for domain wall motion in the nonlinear material response of the soft PZT under ac electric fields