Contribution of Stable Crack Extension to Variable Amplitude Fatigue Crack Growth

Abstract

Variable-amplitude fatigue is invariably associated with periodic tensile overloads that can induce static crack extension component in addition to fatigue crack growth. A simple equation is proposed to account for the static crack growth component. The procedure is validated against fractographic evidence from a programmed load sequence. Accounting for static crack extension is likely to improve cycle-by-cycle crack growth modeling and may also explain scale effects.