A Plane Strain Core Model for Crack Growth in Ductile Materials

Abstract

Abstract It is shown in the present paper that neither plane stress nor plane strain model can accurately simulate ductile fracture tests on ungrooved specimens. Three dimensional effects on the stress distribution at the crack tip must be considered. A moving plane strain core model is thus used in the simulation. For the moving plane strain core model, the deformation in a small region surrounding the crack tip is assumed to be in a state of plane strain and that of the rest of the specimen is in plane stress. With the plane strain core model, it is found that stresses at the crack tip remain constant during steady quasi-static crack growth for ungrooved specimens. For the specimens simulated, the stress at a critical distance from crack tip is independent of specimen size.