Modeling of the Fracture Behavior Sample Dependence on the Stress State Stiffness Coefficient at the Crack Tip

This paper presents an interdisciplinary approach to fracture analysis, combining computational methods of fracture mechanics with traditional materials science analysis of microstructure. A new method for assessing a material's susceptibility to brittle or ductile fracture is proposed, based on the introduction and analysis of a stress stiffness coefficient distributed along the crack front. An algorithm for numerically calculating this parameter has been developed, which enables establishing its relationship with T-stresses and the radius of the plastic zone. It has been found that with a small plastic zone radius and near-zero T-stresses, there is an increased susceptibility to brittle fracture, whereas higher values of these parameters lead to the formation of a "softer" stress state and a transition to a ductile fracture mode. The obtained results help bridge the existing methodological gap between fractographic analysis and quantitative methods of fracture mechanics and can be utilized to predict the fracture behavior of structural materials.