A PIEZOELECTRIC PSEUDOSHEAR MULTILAYER ACTUATOR

A type of high strain piezoelectric ceramic actuator, namely, pseudosh ear multilayer actuator, is described. In this structure, a stack of p repoled rectangular piezoelectric transducer ceramic sheets are conduc tively bonded at alternate ends, while the bottom layer bonded on a fi xed 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 pe rpendicular to the bonding direction. Experimental results indicate th at more than 50 mu m displacement can be achieved from the top layer f or an actuator consisting of 18 layers with dimensions of 25.57 mmX4.0 2 mmX0.51 mm (1XwXt). By reducing ceramic sheet thickness and using mo re layers, even large displacement can be obtained, and driving voltag e can also be reduced while keeping the same field level. Nonlinear pi ezoelectric response under high driving field further enhances the dis placement level. (C) 1998 American Institute of Physics.