Influence of Triaxial Stress State on Damage Evolution in Solids

The continuum mechanical simulation of microstructural damage process is important in the study of ductile fracture mechanics. In these analyses an essential feature is the strong influence of stress triaxiality ratio, i.e. the ratio of mean stress to equivalent stress, on the rate of damage growth. The damage growth rate depends exponentially on the triaxiality ratio. In this paper finite element simulation of damage evolution and fracture initiation in ductile solids will be investigated. A fully coupled constitutive elastic-plastic-damage model has been implemented. The stress update algorithm for the constitutive model is presented together with the consistent tangent operator, which is needed for implicit FEA. Simulations are performed and the results are compared with the numerical and experimental results in the literature and good agreement was found between them.