Revisiting the crack closure and its effect on fatigue life of components.

The present article reviews plasticity, roughness, and oxide-induced crack closure and its direct effect on fatigue crack propagation (FCP) problems. In such cases, plasticity-influenced crack closure significantly influences number of cycles to failure. Thus effective value of crack driving force for fatigue crack propagation problems is dependent upon assessment of plasticity effect both in front of crack tip and in the wake of the advancing crack in the form of appendages of plasticity affected material. Crack closure (through plasticity) is affected by plane stress and plane strain transition, and effect of both types of conditions can be implemented to predict FCP, by taking into consideration appropriate value of plasticity constraint factor. Crack growth under fatigue loading conditions subjected to constant amplitude loading, single overloads, block overloads, variable amplitude loading and random loading is influenced by crack closure effect strongly during transition from plane stress (PSS) to plane strain (PSN) conditions. [ABSTRACT FROM AUTHOR]