EFFECTS OF NONLOCAL DAMAGE IN POROUS PLASTIC SOLIDS

A nonlocal constitutive formulation for a porous ductile material is i nvestigated, in which delocalization relates to the damage mechanism. An elastic-viscoplastic material model is used, with delocalization in corporated in terms of an integral condition on the rate of increase o f the void volume fraction. Two model problems are analysed to study t he effect of including this material length, one relates to localizati on of plastic flow in shear bands, while the other considers a metal m atrix composite. Both model problems involve final failure in strongly nonhomogeneous strain fields, and it is shown that the inherent mesh sensitivity of the numerical failure predictions can be removed by usi ng the nonlocal material model considered here.