Development of Numerical Hydrogen Diffusion-Stress-Crack Growth Simulation System

In this study, we develop a Python-based simulation code for crack growth due to hydrogen embrittlement. A multiphysics numerical model combining stress-assisted hydrogen diffusion, trapping effects, and Paris’ law-based crack propagation is systematically verified for numerical stability and physical plausibility. Specifically, (1) implementation and verification of a stress-driven hydrogen diffusion model, (2) evaluation of mass conservation for lattice and trap hydrogen, (3) crack-tip stress field assessment and concentration coupling, and (4) implementation of a crack-growth algorithm extending Paris’ law for a hydrogen environment, followed by a sensitivity analysis. The results show that the improved code structure and interpolation strategy reduced unphysical numerical errors, and sensitivity analyses quantified the influence of factors such as the diffusion coefficient, trap density, and Paris parameters. The simulation system developed in this study can serve as a design analysis platform for hydrogen-embrittlement-prone structural systems, such as high-strength steel hydrogen storage vessels, offshore installations, and hydrogen-fuel infrastructure. Future work should include a quantitative comparison with experimental data and extension to multiaxial stress conditions.