A piezoelectric pseudoshear multilayer actuator

A type of high strain piezoelectric ceramic actuator, namely, pseudoshear multilayer actuator, is described. In this structure, a stack of prepoled rectangular piezoelectric transducer ceramic sheets are conductively bonded at alternate ends, while the bottom layer bonded on a fixed base. When driven, alternate layers elongate or shrink in the same direction through converse piezoelectric effect, which results in the actuator structure developing a strong sheer motion about the face perpendicular to the bonding direction. Experimental results indicate that more than 50 mu m displacement can be achieved from the top layer for an actuator consisting of 18 layers with dimensions of 25.57 mmX4.02 mmX0.51 mm (1XwXt). By reducing ceramic sheet thickness and using more layers, even large displacement can be obtained, and driving voltage can also be reduced while keeping the same field level. Nonlinear piezoelectric response under high driving field further enhances the displacement level. (C) 1998 American Institute of Physics.