V. Tvergaard et A. Needleman, EFFECTS OF NONLOCAL DAMAGE IN POROUS PLASTIC SOLIDS, International journal of solids and structures, 32(8-9), 1995, pp. 1063-1077
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.