Influence of Material Constitutive Laws onEffective Crack Resistance in Heterogeneous Materials

In this work, we investigate the simulation-based determination of the effective fracture resistance of porous materials while accounting for nonlinear, ductile material behavior. Following the approach of Hossain et al. [1], numerical experiments with surfing boundary conditions are conducted to identify the effective crack resistance as a macroscopic material parameter. Crack evolution in the microstructure is modeled using a phase-field formulation without prescribing crack paths or growth continuity. The maximum value of the macroscopically acting J-integral defines the driving force required for sustained macroscopic crack advance and is taken as the effective fracture resistance. In contrast to previous studies, a von Mises plasticity model is employed to investigate ductile fracture in porous metals. The results show that the effective fracture resistance is governed primarily by the energy dissipation capacity of the material during crack renucleation at pores rather than by tensile strength or microscopic fracture energy. A complementary three-dimensional model confirms these findings, showing similar saturation behavior of the effective fracture resistance with respect to microstructural wall width and good quantitative agreement with the two-dimensional predictions.