In situ estimation of fatigue crack parameters by digital image correlation under cyclic loading with single overload

Abstract

The paper represents the investigation of crack propagation in aluminium alloy AA2024 in a case of constant cyclic loading with single overload. The parameters of the process were evaluated by means of optical and noncontact digital image correlation technique which allows precise in situ measurements and provides local strain data. There have been analysed strain fields, local strains at the crack tip and crack closure level in order to reveal the effect of overload on crack growth parameters. Results are consistent with published data and developed mathematical models - the highest impact is emerged when crack extended into overload plastic zone by 30%.