Fatigue crack growth model for a thin steel plate containing hydrogen

A method of predicting fatigue crack growth in hydrogen-charged thin steel plates is proposed. It consists in computing modified stress intensity factors which reflect the presence of hydrogen, and using them in a fatigue crack growth equation for an uncharged plate. The modification accounts for both, hydrogen embrittlement of crack tips and hydrogen-induced residual stresses in the plate. The new stress intensity factors are derived for two special cases – uniform and stationary hydrogen distribution in the plate. With their use bounds are established on the rate of hydrogen-assisted fatigue crack growth. Theoretical results are illustrated by numerical calculations.