Two models to simulate rate-dependent domain switching effects—application toferroelastic polycrystalline ceramics

Abstract

The aim of this paper is to study rate-dependent switching in ferroelastic materials. Morespecifically, a micro-mechanically motivated model is embedded into an iterativethree-dimensional and electromechanically coupled finite-element framework. Anestablished energy-based criterion serves for the initiation of domain switching processes asbased on reduction in (local) Gibbs free energy. Subsequent nucleation and propagation ofdomain walls is captured via a linear kinetics theory with rate-dependent effects beingincorporated in terms of a deformation-dependent limit-time parameter. Withthis basic model in hand, two different switching formulations are elaborated inthis work: on the one hand, a straightforward volume-fraction ansatz is appliedwith the volume-fraction value depending on the limit-time parameter; on theother hand, a reorientation–transformation formulation is proposed, whereby theorientation tensor itself is assumed to depend on the limit-time parameter. Macroscopicbehaviour such as stress versus strain curves or stress versus electrical displacementgraphs are obtained by applying straightforward volume-averaging techniquesto the three-dimensional finite-element-based simulation results which providesimportant insights into the rate-dependent response of the investigated ferroelasticmaterials.