Elastoplastic fracture of a plate with two edge cracks

The strength of a rectangular plate with two opening-mode (mode I) edge cracks was studied using the Neuber–Novozhilov approach and a modified Leonov–Panasyuk–Dugdale model with nonzero prefracture zone. A coupled discrete-integral fracture criterion is used since the stress field in the vicinity of the crack tip has a singularity. At the tip of a real crack, the fracture criterion for ultimate strain is satisfied, and at the tip of the model crack, the criterion for normal stresses is satisfied. The constitutive equations for the analytical model are analyzed. Simple formulas for fracture load in quasi-brittle and quasi-ductile fracture are derived. Plate fracture curves are constructed for a plane stressed state.