Modified Neuber–Novozhilov criterion of rupture for V-shaped cuts (antiplane problem)

A modified Neuber–Novozhilov criterion of rupture is proposed to study the fracture in the vicinity of the tip of a V-shaped cut. In this criterion, the limits of averaging stresses at the cut axis depend on the presence, size, and location of defects in the initial material. The lattice parameter of the initial material is taken to be the characteristic linear size. For V-shaped cuts, simple relations between the stress-intensity factor of the modified singularity factor, the singularity factor itself, and the theoretical shear strength of a single crystal of the material with allowance for damage in the vicinity of the tip are proposed. These relations admit passage to the limit with respect to the angle from a V-shaped cut to a crack. It is shown that the classical critical stress-intensity factor used to estimate the strength of cracked bodies is not a material constant.