Energy considerations of PZT multilayer actuators under dynamic driving conditions

By means of fast optical two channel elongation measurement, with a resolution of 0.05 μm, the dynamic behavior of PZT multilayer stack actuators, consisting of some layers and with typical dimensions of 10×10×20 mm³, driven under different clamping conditions is investigated. In addition to the deflection measurement, the electrical power consumption and the dynamic and static forces are measured simultaneously. Starting from the measurement of the working characteristics, including the determination of dynamic stiffness and blocking force, the mechanical output for different mechanical preloads and for different mechanical stiffnesses of load is evaluated. Choosing the optimum preload and stiffness of load, maximum mechanical output can be achieved. It can be shown that the mechanical load also influences the electrical power consumption of the clamped actuator. Depending on the composition of the PZT ceramic, the clamping conditions may cause depolarization. Under driving conditions additional repolarization effects induce increased deflection. This can be used to find optimum material compositions for given mechanical preloads of clamped actuators