Recent Advances in Experimental and Computational Studies of Fatigue Crack Growth in Metals —From the Industrial Point of View—

Abstract

Estimating fatigue damage is essential to ensure the safety of mechanical structures. In this paper, recent experimental and computational approaches for fatigue crack growth in metals are discussed from the industrial viewpoint. First, experimental studies for obtaining the accurate threshold stress intensity factor range ΔK_th and the effect of hydrogen on the fatigue crack growth are reviewed. In particular, we discuss the relationship between the loading frequency and the magnitude of oxide-induced crack closure, the methodology of achieving an accurate ΔK_th value and the difference between fatigue crack growth curve in gaseous hydrogen and that in air. Moreover, key factors to be considered for computation of actual fatigue crack growth behavior are reviewed. Second, computational methods on fatigue crack propagation are surveyed, where those of complex crack propagation phenomena in real mechanical structures, including crack separation and merging, are studied. Especially, we focus on the effect of the models of crack front line on the choice of computational methods.