Coupled chemical–mechanical damage modeling of hydrogen-induced material degradation

The automotive industry faces significant challenges in achieving climate targets and becoming CO${}_2$ neutral. To reduce the weight of body in white specially in electrical vehicles, advanced high-strength and ultra-high-strength steels are utilized. These steels must resist hydrogen-induced softening and ductile/cleavage damage during the production process. A stress-state dependent coupled chemical–mechanical damage mechanics model is developed in implicit and explicit versions to predict hydrogen-induced damage in CP1000 steel. In-situ Slow-Strain-Rate-Tests under hydrogen loading serve to validate the model and show the significant impact of stress-state on hydrogen diffusion. Both models accurately predict damage initiation, evolution, and fracture under hydrogen influence.