Recent developments in fatigue crack growth assessment

Abstract This paper examines the fatigue crack growth histories, at low to mid range Δ K ’s, for a range of aircraft aluminium alloys, test specimens and service loaded components. It concludes that the crack growth history shows that, as a first approximation, there is a log–linear relationship between the apparent crack length or depth and the life ( N ), respectively. This leads to the further observation that, for the range of materials and spectra considered here, there is a linear relationship between the crack growth rate and the crack length when plotted on a log–log scale.