Fatigue crack growth behaviour and life prediction for 2324-T39 and 7050-T7451aluminium alloys under truncated load spectra

摘要

This paper presents a study of crack growth behaviour in aluminium alloys 2324-T39 and 7050-T7451 subjected to flight-by-flight load spectra at different low-stress truncation levels. Crack branching was observed in the higher truncationlevels for the 2324 and in all truncation levels for the 7050. Mode I crackgrowth life can be predicted for the 2324 alloy by the NASGRO equation and theGeneralised Willenborg retardation model. However, quantitative prediction ofthe fatigue life of a significantly branched crack is still a problem. Materialproperties, test sample’s orientation and applied stress intensity factor rangeall play dominant roles in the fracture proces