UNIQUENESS AND LOCALIZATION .2. COUPLED ELASTOPLASTICITY

Uniqueness of the incremental response is investigated for an elastoplastic coupling model with elastic stiffness degradation. The criteria of second order work positiveness and strain localization are used in the form derived by Bigoni and Hueckel (1991, Int. J. Solids Structures 28, 197-213). A numerical example shows that in a triaxial test the loss of second order work positiveness occurs at the positive hardening modulus, whereas the condition of strain localization is never fulfilled. Thus shear bands or splits are predicted not to form, despite strong elasticity degradation and non-associativity.