Electro-mechanical coupling in 8/65/35 PLZT

This work presents the experimental characterization of 8/65/35 PLZT subjected to stress and electric field loading above the coercive field. Strain vs. electric field and electric displacement vs. electric field hysteresis loops as well as stress vs. strain and stress vs. electric displacement are measured. The limitations of linear constitutive modeling and the limitations of large strain ferroelectrics as actuator materials are examined. The results indicate a stress vs. strain curve that clearly shows the “yield” or ferroelastic switching stress is an important criteria for assessing the capability of actuator ceramics. A low threshold of ferroelastic switching means the piezoelectric effect is easily clamped