A three-dimensional numerical study of mode I crack tip fields in pressure sensitive plastic solids

In this paper, a finite element study of 3D crack tip fields in pressure sensitive plastic solids (such as polymers or metallic glasses) under mode I, small scale yielding conditions is performed. The material is assumed to obey a small strain, Extended Drucker–Prager yield condition. The roles of pressure sensitive yielding, plastic dilatancy and yield locus shape on the 3D plastic zone development and near-crack front fields are systematically studied. It is found that while pressure sensitivity leads to a significant drop in the hydrostatic stress all along the 3D crack front, it enhances the plastic strain and crack opening displacements. The implications of these contrasting trends on ductile fracture processes are discussed in the light of some recent micro-mechanical simulations.