Significance of Stable Crack Extension to Fatigue Crack Growth

Abstract

A long-overlooked aspect of fatigue crack growth is the potential\ncontribution to it, of stable crack extension (SCE). Reduction in\nspecimen size and increase in magnitude of cyclic loading will induce\nincreased contribution of SCE. SCE as a load interaction effect is\nmanifest in disproportionately high crack extension due to periodic\noverloads. SCE can exceed by more than an order of magnitude estimates\nof crack growth from the da/dN versus DK relationship. Simple equations\nare proposed to account for SCE in fatigue crack growth. A numerical\nanalysis is performed to characterize the significance of SCE to\nconstant amplitude and variable amplitude fatigue crack growth.