The effect of stress-triaxiality on growth of a void in a three dimensionalsingle-crystal face-centered-cubic (FCC) lattice has been studied. Moleculardynamics (MD) simulations using an embedded-atom (EAM) potential for copperhave been performed at room temperature and using strain controlling with highstrain rates ranging from 10^7/sec to 10^10/sec. Strain-rates of thesemagnitudes can be studied experimentally, e.g. using shock waves induced bylaser ablation. Void growth has been simulated in three different conditions,namely uniaxial, biaxial, and triaxial expansion. The response of the system inthe three cases have been compared in terms of the void growth rate, thedetailed void shape evolution, and the stress-strain behavior including thedevelopment of plastic strain. Also macroscopic observables as plastic work andporosity have been computed from the atomistic level. The stress thresholds forvoid growth are found to be comparable with spall strength values determined bydynamic fracture experiments. The conventional macroscopic assumption that themean plastic strain results from the growth of the void is validated. Theevolution of the system in the uniaxial case is found to exhibit four differentregimes: elastic expansion; plastic yielding, when the mean stress is nearlyconstant, but the stress-triaxiality increases rapidly together withexponential growth of the void; saturation of the stress-triaxiality; andfinally the failure.
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