Influence of Preload on the Properties for Piezoelectric Stack Actuator

As the piezoelectric stack actuator can withstand pressure only,a preload device is designed to ensure that the intelligent active member can experience tensile stress. In this paper,a preload experiment is carried out to test the influence of preload on actuator's properties. The results show that the output displacement increases and the hysteresis degree descrease under certain preload. The mechanism is that the crystal structure of the piezoelectric ceramic is changed by the preload and the converse piezoelectric effect is enhanced,leading to the above results when electric field is applied.