Finite element analysis of unimorph rectangular piezoelectric diaphragm actuators with experimental verification

This paper presents a study in which the behavior of clamped unimorph rectangular piezoelectric diaphragms is analyzed and the importance of electrode patterning for enhancement of static displacement is examined. Previous work showed that by regrouping the electrode pattern of a clamped-circular diaphragm actuator the maximum static deflection increased by nearly an order of magnitude in response to an electric field. To extend this concept and determine the effects of electrode patterns and the shape of the piezoelectric layer on the actuator's static displacement the rectangular diaphragm actuators are analyzed by the finite element method. Experiments for the three different cases of rectangular actuators are also carried out to validate the models. It was found that the measured static deflections for the clamped rectangular actuators are in accordance with analytical results and regrouping the electrode pattern on a rectangular actuator can increase deflection by an order of magnitude, and subsequently volumetric displacement, by over four times compared to the unmodified (fully covered) case.