Theoretical justification for the association of a critical net-section stress with fracture initiation at a crack tip

Abstract This paper provides theoretical justification for the association of a critical net-section stress with fracture initiation after general yield at a crack tip in a ductile material. The justification relies on demonstrating that the attainment of critical values of the crack tip characterising parameters, Crack Opening Displacement and J integral, correlates with a critical net-section stress which, subject to conditions specified in the paper, is independent of geometrical parameters.