Phase field modeling of interfacial damage in heterogeneous media with stiff and soft interphases.

• Propose a new interfacial cracking model in the phase field framework. • Consider the effects of both stiff and soft interphases on the fracture behavior of heterogeneous materials. • Simulate the material degradation both on the interface and in bulk within the context of the phase field method for fracture. • Model the competition between the interface and bulk cracking. • Capture the complex cracking phenomena on interfaces such as initiation, delamination, coalescence, deflection. A new interfacial cracking model in the phase field framework is proposed. The developed method is able to capture the effects of both stiff and soft interphases on the fracture behavior of heterogeneous materials. A dimensional-reduced model based on a rigorous asymptotic analysis is adapted to derive the zero thickness imperfect interface models from an original configuration containing thin interphase. Then, the energetic approach is used to describe the material degradation both on the interface and in bulk within the context of the phase field method for fracture. This technique allows to effectively model the competition between the interface and bulk cracking. Furthermore, a unilateral contact condition is also proposed to ensure the physical crack propagation patterns in the case of spring imperfect interface. The complex cracking phenomena on interfaces such as initiation, delamination, coalescence, deflection are successfully predicted by the present method. The numerical implementation using a staggered algorithm provides an extremely robust approach. The performance of the proposed framework is demonstrated through numerical examples involving complex microcracking of both stiff and soft interfaces in complex microstructures. [ABSTRACT FROM AUTHOR]