Modeling nonlinear behaviour of polycrystalline piezoceramics accurately can result in an improvement in the wide range of their application, either as actuator or sensor. Two of the main nonlinear behaviours in piezoceramics are hysteresis and creep. These nonlinear and complex macroscopic behaviours of piezoceramics under an electro-mechanical loading are results of domain wall motion in the microscopic level. We developed a micromechanical model to simulate creep and hysteresis behaviour in a piezoceramic. We considered a polycrystal piezoceramic with a random structural configuration of crystals in an isothermal process. An appropriate finite element method (FEM) was used to solve mechanical and electrical governing equations. Each element in FEM represents a crystal in actual polycrystal piezoceramics. volume fractions are needed to evaluate spontaneous polarization and strain caused directly by switching of tetragonal crystal. We improved the constitutive law introduced by Huber et al. [1] in order to consider the effect of exhausted domains in switching process. We used our model to simulate the electromechanical response of a piezoelectric stack under different loading conditions. Our results show a good qualitative agreement with the published experimental results. This model can predict creep as well as hysteresis.

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