非线性压电效应下压电弯曲执行器的动力分析

研究压电弯曲执行器在强电场作用下的非线性动力行为．考虑电致伸缩和电致弹性的非线性压电效应，导出了压电悬臂执行器变刚度的弯曲振动控制方程．利用非定常振动的渐近理论，讨论了弯曲压电执行器的动力特征．根据目前的非线性模型可以计算压电悬臂执行器的固有共振频率与电场的变化关系．结果表明压电执行器端头挠度谐振幅度随作用电场振幅的增大而增大，以及力学品质因数随电场振幅的增大而减少，并且与实验结果非常吻合．通过数值比较得到在电场频率随时间变化非常缓慢的情况下非定常振动问题可以近似地用定常振动来处理．

The dynamic analysis of piezoelectric bending actuator considering nonlinear piezoelectric effect

In this paper, nonlinear dynamic characteristics of piezoelectric bending actuators under strong electric field are studied. Considering nonlinear piezoelectric effect of the electrostriction and electroelasticity, the bending vibration governing equation of the cantilever piezoelectric actuator, in which the stiffness is variable with time, is obtained. Using the asymptotic theory of nonstationary vibrations, the dynamic characteristics of the cantilever actuator are discussed. The proposed nonlinear model predicts the change in fundamental resonant frequency of piezoelectric cantilever with the variation in electric field. The predicted resonance amplitude of the tip deflections of the piezoelectric actuators, which increase with the increase in the magnitude of the electric field, the decrease in the mechanical quality factor with the increase in the electric field, and well agrees with experimental results. By comparing with predicted results, it is found that the problem of nonstationary vibration can be approximately treated as stationary vibration under the electric field frequency varies very slowly.