On coupled gradient-dependent plasticity and damage theories with a view to localization analysis

Combinations of gradient plasticity with scalar damage and of gradient dama ge with isotropic plasticity are proposed and implemented within a consiste ntly linearized format. Both constitutive models incorporate a Laplacian of a strain measure and an internal length parameter associated with it, whic h makes them suitable for localization analysis. The theories are used for finite element simulations of localization in a o ne-dimensional model problem. The physical relevance of coupling hardening/ softening plasticity with damage governed by different damage evolution fun ctions is discussed. The sensitivity of the results with respect to the dis cretization and to some model parameters is analyzed. The model which combi nes gradient-damage with hardening plasticity is used to predict fracture m echanisms in a Compact Tension test. (C) 1999 Editions scientifiques et med icales Elsevier SAS.