New 2D-Experiments and Numerical Simulations on Stress-state-dependence of Ductile Damage and Failure

The paper deals with a series of new experiments and corresponding numerical simulations to be able to study the effect of stress state on damage and failure behavior of ductile metals. The material behavior is modeled by a continuum approach based on free energy functions defined in damaged and corresponding fictitious undamaged configurations leading to elastic material laws which are affected by damage. Inelastic behavior of ductile materials is modeled by continuum plasticity and continuum damage model, respectively. The present approach takes into account the effect of stress state on damage and failure conditions expressed in terms of the stress intensity, the stress triaxiality and the Lode parameter. Previous studies have shown that it will not be possible to propose the stress-state-dependent functions for damage and failure criteria only based on tests with uniaxially loaded specimens. Therefore, new experiments with carefully designed and two-dimensionally loaded specimens have been developed. Corresponding numerical simulations of these tests show that they cover a wide range of stress states allowing validation of stress-state-dependent functions for the damage criterion and evolution laws for the damage strains.