Application of digital image correlation to the investigation of crack closure following overloads

This paper describes a set of fatigue experiments carried out on 6082 Aluminium CCT specimens. Crack propagation rates and crack opening loads were measured before and after a single overload in an otherwise constant amplitude loading sequence. Crack retardation was observed after the overload, and this was more significant in thin (3 mm) specimens than in thick (25 mm) specimens of otherwise similar geometry. Digital image correlation and...