Development of a piezoelectric induced-strain actuator with an innovative internal amplifying structure

The development of a novel piezoelectric induced-strain actuator possessing an innovative internal amplifying structure is presented in this paper. This actuator basically consists of a metal frame and two lead zirconate titanate (PZT) piezoelectric ceramic patches. The metal frame is bent to form an open trapezoid, where its center part has a specially designed saddle-like unit and its slanting legs are attached with PZT patches. The saddle-like unit has an amplifying-lever mechanism at the corners to increase the displacement output of the whole actuator even its legs are mechanically clamped. When an electric field is applied across the thickness of the PZT patches, the patches induce deformations on the whole actuator through the piezoelectric d31effect. The saddle-like unit can relax the constraints at the joints between the unit and the legs by stretching itself during bending. Piezoelectric finite element analysis is used to maximize the work output of displacement and blocked force of the actuator under different geometric parameters. The results are in good agreement with those obtained from quasi-static measurements, showing that the actuator has work output comparable to and larger than the existing induced-strain actuators (e.g., THUNDER) under fixed mounting conditions. Therefore, the actuator has great potential for use in various practical smart structures and integrated systems, including active-passive vibration isolation and micro-positioning.