It is well established that spall fracture and other rapid failures in ductile materials are often dominated by nucleation and growth of micro-voids. In the present work, a mechanistic model for failure by cumulative nucleation and growth of voids is fully coupled with the thermo-elastoplastic constitutive equations of the Mechanical 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, rate sensitivity, fracture surface energy, and nucleation frequency. The MTS model used for plasticity includes the superposition of different thermal activation barriers for dislocation motion. Results obtained in the case of uncoupled and coupled model of plasticity and damage from the simulations of the planar impact with cylindrical target, are presented and compared with the experimental results for OFHC copper. This comparison shows the model capabilities in predicting the experimentally measured free surface velocity profile as well as the observed spall and other damage patterns in the material under impact loading. These results are obtained using the finite element code Abaqus/Explicit.