A physically consistent and quantitative phase-field model for anisotropic fracture in brittle multiphase solids

This work presents a physically consistent phase-field model for simulating fracture in anisotropic brittle solids, with a focus on preserving a uniform crack interface width across different phases in multiphase materials. This is achieved by incorporating anisotropy coherently into both the gradient and potential terms of the regularized crack surface energy. Theoretical relations between anisotropy parameters and critical fracture properties are systematically derived using an Iterative Graphical Method based on the Generalized Maximum Energy Release Rate criterion. Benchmark simulations confirm quantitative agreement with theory across a wide anisotropy parameter space. Compared to existing anisotropic fracture phase-field models, the present formulation shows improved predictive capabilities, quantitatively capturing both crack deflection behavior and critical energy release rates. This work serves as the first comprehensive analysis of a consistent approach to incorporating anisotropic crack resistance into phase-field fracture models, significantly enhancing their fidelity and applicability to complex multiphase materials.