Experiments and Numerical Simulations on Stress-State-Dependence of Ductile Damage Criteria

Abstract

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 behavior of ductile metals. In this context, a thermodynamically consistent anisotropic continuum damage model is presented. It takes into account the effect of stress state on damage and failure conditions as well as on evolution equations of damage strains. Different branches of the respective criteria are considered corresponding to various damage and failure mechanisms depending on stress intensity, stress triaxiality and the Lode parameter. Since it is not possible to propose and to validate stress-state-dependent criteria only based on tests with uniaxially loaded specimens for a wide range of stress states, new experiments with two-dimensionally loaded specimens have been developed. Corresponding numerical simulations of these experiments show that they cover a wide range of stress triaxialities and Lode parameters in the tension, shear and compression domains. The new series of experiments allow validation of stress-state-dependent functions for the damage criteria and are used to identify parameters of the continuum model.