Multi phase-field modeling of anisotropic crack propagation in 3D fiber-reinforced composites based on an adaptive isogeometric meshfree collocation method

An anisotropic multi phase-field model is developed in this paper to investigate the interaction between the crack propagation and interfacial damage in a fiber-reinforced composite. The proposed modeling approach can capture the fracture patterns of composite microstructures through the introduction of the crack phase field and the interface phase field. By considering the free energy related to the interface and crack phase fields, the interfacial debonding, matrix cracking and the interaction of two fracture patterns can thus be simulated. The anisotropic phase-field approach is further adopted to describe the interface interaction associated with a crack. The phase-field equations are solved using the isogeometric-meshfree collocation approach to achieve high computational efficiency. An adaptive h-refinement scheme is incorporated into the phase-field formulations using phase-field variables and their gradients as the error indicators. The proposed method is shown to be effective and robust in both case studies of 2D and 3D fiber-reinforced composite microstructures. Moreover, fracture behaviors including the crack initiation, propagation, coalescence, interfacial debonding, and matrix cracking in composite microstructures are found to be precisely modeled by the proposed approach.