STRESS ANALYSIS AND GEOMETRICAL CONFIGURATION SELECTION FOR MULTILAYER PIEZOELECTRIC DISPLACEMENT ACTUATOR

摘要

Multilayer piezoelectric ceramic displacement actuators are susceptible to cracking in the region near the edge of the internal electrode, which may cause system damage or failure. In this paper, the stress distribution of a multilayer piezoelectric composite is investigated in a working environment and the optimized geometrical configuration of the piezoelectric layer is obtained. The stress distribution in the structure and the stress concentration near the edge of the internal electrode, induced by non-uniform electric field distribution, are analyzed by moire interferometry experiment and finite element numerical simulation. Based on the above analysis, two optimized geometrical models are presented for the purpose of geometrical configuration selection, with which stress concentration can be reduced significantly while the feasibility of the machining process and the basic structural functions occurring in the conventional model are retained. The numerical results indicate that the maximum stress in the optimized models is effectively diminished compared to the conventional model. For instance, the peak value of the principal stress in the optimized model II is 93.1% smaller than that in the conventional model. It is proved that stress concentration can be effectively relaxed in the latter of the two optimized models and thus the probability of fracture damage can be decreased.