Cohesive zone phase field model for electromechanical fracture in multiphase piezoelectric composites

This paper introduces a coupled electromechanical finite deformation phase field model for crack propagation and interfacial decohesion in multiphase piezoelectric composites with interfaces. The crack phase field model is augmented with cohesive traction-separation laws at the material interfaces, derived from a cohesive potential function. A Gibbs free energy density function is proposed, allowing for the incorporation of the anisotropic elastic stiffness of the piezoelectric material. Numerical simulations exhibiting different failure mechanisms are carried out to demonstrate the efficacy of the model. Effects of external electric field on crack evolution and the competition between penetration and deflection of a crack impinging on an interface are investigated. Limited verification tests are conducted with theoretical results. Finally, the model is used to simulate fracture in nonuniform piezocomposite microstructures. The effect of crack propagation on the evolution of the electric field with different crack face conditions are analyzed. Differences in the electromechanical responses of piezocomposites due to different fiber distributions are also observed.