A Continuum Damage Model Based on Experiments and Numerical Simulations—A Review

Abstract

AbstractThe paper summarizes the author’s activities in the field of damage mechanics. In this context, a thermodynamically consistent anisotropic continuum damage model is reviewed. The theory is based on consideration of damaged as well as fictitious undamaged configurations. The modular structure of the continuum model is accomplished by kinematic decomposition of strain rates into elastic, plastic and damage parts. A generalized yield condition is used to adequately describe the plastic flow properties of ductile metals and the plastic strain rate tensor is determined by a non-associated flow rule. Furthermore, a stress-state-dependent damage criterion as well as evolution equations of damage strains are proposed. Different branches of the respective criteria are considered corresponding to various damage and failure mechanisms depending on stress state. 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, numerical calculations on the micro-level have been performed to be able to study stress-state-dependent mechanisms of micro-defects and their effect on macroscopic behavior. In addition, 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.KeywordsDuctile damageStress triaxialityLode parameterExperimentsNumerical simulations