Behaviour of a unimorph circular piezoelectric actuator

This paper investigates the deflected behavior of unimorph circular piezoelectric diaphragm actuators under electrical loading. Among many other factors that affect the actuators' performance, the effects of the boundary conditions, the thickness ratio of piezoelectric to substrate layers, and the radius of piezoelectric layer bonded to the metallic substrate on the resulting deflection of circular actuators are examined. Analytical models are presented with which to optimize the thickness ratio, and the radius ratio of piezoelectric to substrate for various boundary conditions. Experimental results for two circular actuators with different piezoelectric coverage are also demonstrated to validate the models. The measured deflections for the experimentally tested clamped diaphragms show close correlation with the analytical transverse deflections for elastically supported edge. The analytical solutions presented here can be used to optimize the transverse deflection of circular piezoelectric diaphragm actuators.