Brief note-A criterion for unstable elastic-plastic brittle fracture based on more realistic model under plane stress

A criterion for unstable elastic-plastic brittle fracture under plane stress was previously proposed based on energy balance considerations, in which the plastic work term was used based on Dugdale model of plastic zone pattern. The realistic pattern, however, of the plastic zone is far from a Dugdale model. Therefore, in this article, a more realistic pattern is used. As a result, a more realistic criterion for unstable elastic-plastic brittle fracture has been obtained. In this new criterion, γ+p appears in place of the material surface energy term γ in the previous criterion, where p is the plastic work term corresponding to the excess plastic zone pattern extending in the direction perpendicular to the crack propagation direction beyond over the boundary of Dugdale model.