Improving bending-mode response of piezoceramic actuators under high electric field by modification of material parameters

Abstract

Linear constitutive equation of piezoelectricity is derived by neglecting the higher order terms in Tayler series expansion of Gibbs potential. At higher electric field, the contribution of higher order terms is significant and linear constitutive equation cannot be used to predict response of piezoelectric actuator. In this paper, a new technique of modification of material parameters (elastic coefficients and piezoelectric strain coefficient) in the linear constitutive equation of piezoelectricity, is proposed to simulate the nonlinear response of piezoceramic actuator. A piezoelectric bimorph (PB) is fabricated to validate the nonlinear response of piezoceramic actuator in bending mode under high electric field. Shear deformation beam theory is used to model the PB and superconvergent finite element with Hamilton principle is used to obtained the numerical solution of PB. Linear and nonlinear tip deflection of PB is compared with the experimental results. The deviation of measured tip deflection from the simulated linear response of PB has increased with the increase of the applied electric field. At 0.2 kV/mm the deviation is approximately 39\% from the linear response. A modification in material parameters is done to simulate the nonlinear response of PB. As a result, the nonlinear response of PB predicts the experimental results quite accurately.