A physically-based and fully coupled model of elasto-plasticity and damage for dynamic failure in ductile metals
Résumé
It is well established that spall fracture and other rapid failures in ductile materials are oftenominated by nucleation and growth of micro-voids. In the present work, a mechanistic model for failureby cumulative nucleation and growth of voids is fully coupled with the thermo-elastoplastic constitutiveequations of theMechanical Threshold Stress (MTS) which is used to model the evolution of the flow stress.The damage modeling includes both ductile and brittle mechanisms. It accounts for the effects of inertia, ratesensitivity, fracture surface energy, and nucleation frequency. The MTS model used for plasticity includesthe superposition of different thermal activation barriers for dislocation motion. Results obtained in thecase of uncoupled and coupled model of plasticity and damage from the simulations of the planar impactwith cylindrical target, are presented and compared with the experimental results for OFHC copper. Thiscomparison shows the model capabilities in predicting the experimentally measured free surface velocityprofile as well as the observed spall and other damage patterns in the material under impact loading. Theseresults are obtained using the finite element code Abaqus/Explicit.