An equivalent thickness conception for prediction of surface fatigue crack growth life and shape evolution

Based on the newly developed equivalent-thickness-based fatigue crack closure evaluation, a surface fatigue crack model is proposed for evaluating the growth rate at each point on the crack border from material base curves obtained by standard straight-through cracked specimens. Using this model, surface fatigue crack propagations in specimens with different initial shapes are predicted through detailed finite element simulations. Good coincidence between the predictions and available experimental results shows that the equivalent thickness conception can serve as a realistic bridge from fatigue crack growth base curves from standard specimens to fatigue crack growth life prediction for three-dimensional engineering structures.