Transient Hydrogen Diffusion/Elastoplastic Coupling Analysis for Predicting Fatigue Crack Growth Acceleration of Low-Carbon Steel in Gaseous Hydrogen

In recent years, hydrogen, one of renewable energy, has attracted attention. For widespread commercialization of the hydrogen-energy systems, a useful and reliable evaluation method should be developed for capturing the degradation of strength and fatigue properties of metals in presence of hydrogen. This paper implemented transient hydrogen diffusion-elastoplastic coupling analysis program into a commercial software of Finite Element Analysis (Abaqus) to predict the fatigue crack growth (FCG) acceleration of a low carbon steel (JIS-SM490B) in high-pressure hydrogen gas. For this simulation, hydrogen-diffusion properties (concentration and diffusivity) depending on plastic strain were experimentally obtained. Our thorough numerical results proposed a practical technique to predict an onset of hydrogen-enhanced FCG acceleration measured in experiments, via the numerically obtained gradient of hydrogen concentration at the crack tip. In addition, a practical technique to predict the hydrogen-enhanced FCG acceleration ratio was also discussed based on the gradient of hydrogen concentration.