Phase-field simulation of dual-crack system hydrogen embrittlement in metallic materials

Abstract

Hydrogen embrittlement is a severe form of failure in metallic materials, where hydrogen ions significantly reduce the load-bearing capacity of the material. The presence of hydrogen and multiple cracks complicates the fracture process, rendering fracture prediction considerably more challenging. In this work, we employ the standard phase-field damage model to investigate the propagation of dual cracks based on the hydrogen-enhanced decohesion mechanism (HEDE). Furthermore, we have enhanced the iteration approach of the phase-field method by introducing Anderson acceleration and over-relaxation as complementary strategies on top of the staggered solution scheme. This modification significantly reduces the number of iterations, thereby achieving efficient solutions. Additionally, this paper comprehensively considers the influence of various crack factors, under different crack arrangement configurations, on both the material's load-bearing capacity and the interaction among cracks. These arrangements include horizontal, inclined, collinear, parallel, internal, and boundary positions. The influencing factors encompass crack length, crack tilt angle, the lateral spacing between cracks, the vertical spacing between cracks, and the distance between cracks and boundaries. Through numerical simulations, universal patterns of the influence of various crack factors on the fracture behavior of a dual-crack system in a hydrogen environment were identified. It was demonstrated that when the influence regions of two cracks overlap, it significantly affects their propagation paths and reduces the model's load-carrying capacity.