Nonlocal effects on localization in a void-sheet

Abstract

For a nonlocal damage model it is expected that the characteristic material length relates to the damage mechanism. In the case of ductile fracture the most relevant length scales would be the average void radius or spacing. Cell model computations representing a single row of voids in an infinite solid under plane strain conditions are here used to compare with predictions of a nonlocal version of a porous ductile material model. Both the critical strain for the onset of plastic flow localization and the slope of the stress-strain curve in the post-localization range are compared, and it is found that both of these are affected by the value of the material length in the nonlocal model. Comparison with predictions of the void-sheet cell model are carried out for an inclined row of voids, leading to shear band failure, as well as a row of transversely aligned voids. For shear bands the material characteristic length scales with the void radius, whereas for transversely aligned voids the scaling is with the void spacing.