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Plasticity Induced by Shock Waves in Nonequilibrium Molecular-Dynamics Simulations
Brad Lee Holian,Peter S. Lomdahl +1 more
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In this article, nonequilibrium molecular-dynamics simulations of shock waves in three-dimensional 10-million atom face-centered cubic crystals with cross-sectional dimensions of 100 by 100 unit cells were presented.Abstract:
Nonequilibrium molecular-dynamics simulations of shock waves in three-dimensional 10-million atom face-centered cubic crystals with cross-sectional dimensions of 100 by 100 unit cells show that the system slips along all of the available {111} slip planes, in different places along the nonplanar shock front. Comparison of these simulations with earlier ones on a smaller scale not only eliminates the possibility that the observed slippage is an artifact of transverse periodic boundary conditions, but also reveals the richness of the nanostructure left behind. By introducing a piston face that is no longer perfectly flat, mimicking a line or surface inhomogeneity in the unshocked material, it is shown that for weaker shock waves (below the perfect-crystal yield strength), stacking faults can be nucleated by preexisting extended defects.read more
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Exceptionally high spallation strength for a high-entropy alloy demonstrated by experiments and simulations
TL;DR: In this article , the performance of the Cantor alloy at the ultra-high deformation rates of shock waves was studied using both experiments and atomistic simulations, and the difference between experiments and simulations can be explained by the difference in strain rate.
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Investigation of the elastically shock-compressed region and elastic–plastic shock transition in single-crystalline copper to understand the dislocation nucleation mechanism under shock compression
TL;DR: In this article, the authors present a molecular dynamics simulation of the shock compression of a Cu single crystal along the 〈110〉 direction specifically focusing on the mechanisms observed in the elastically compressed and the elastic-plastic transition regions.
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Void collapse and subsequent spallation in Cu50Zr50 metallic glass under shock loading by molecular dynamics simulations
TL;DR: In this paper, large-scale molecular dynamics simulations are used to investigate the shock loading of Cu50Zr50 MG, including thermodynamic quantities, shock-induced void collapse, and spall behavior.
Journal ArticleDOI
Shock-induced plasticity in nanocrystalline iron: Large-scale molecular dynamics simulations
Hoang-Thien Luu,Ramon Ravelo,Martin Rudolph,Eduardo M. Bringa,Timothy C. Germann,David Rafaja,Nina Gunkelmann +6 more
TL;DR: In this paper, large-scale nonequilibrium molecular dynamics (MD) simulations of shock waves in nanocrystalline iron show evidence of plasticity before the polymorphic transformation takes place and the atomistic structure in the shock direction shows an elastic precursor, plastic deformation and shock-induced phase transformation from bcc to hcp iron.
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Mesoscale simulations of shockwave energy dissipation via chemical reactions
TL;DR: In this paper, the authors use a particle-based mesoscale model that incorporates chemical reactions at a coarse-grained level to study the response of materials that undergo volume-reducing chemical reactions under shockwaveloading conditions.
References
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Journal ArticleDOI
Shock-wave structure via nonequilibrium molecular dynamics and Navier-Stokes continuum mechanics
TL;DR: In this article, a strong steady dense-fluid shock wave is simulated with 4800-atom nonequilibrium molecular dynamics, and the resulting density, stress, energy, and temperature profiles are compared with corresponding macroscopic profiles derived from Navier-Stokes continuum mechanics.
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Fracture simulations using large-scale molecular dynamics
Brad Lee Holian,Ramon Ravelo +1 more
TL;DR: It is found that the can suppress ductile behavior by including viscous damping in the equations of motion, thereby demonstrating a transition to brittle crack propagation as static, zero-strain-rate conditions are approached.
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Dislocation Dynamics and Dynamic Yielding
TL;DR: In this article, the dislocation dynamics of Gilman and Johnston were applied to the problem of elastic elastic flow in Armco iron at very high strain rates, and the initial density of dislocation lines, N0, was found to be 2.0×108 cm−2.
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Large-Scale Molecular Dynamics Simulations of Three-Dimensional Ductile Failure
TL;DR: In this paper, the authors performed massively parallel 3D molecular dynamics simulations with up to 35 million atoms to investigate ductile failure, obtaining mechanistic information at the atomistic level inaccessible to experiment.
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A mechanism for dislocation generation in shock-wave deformation
TL;DR: Hornbogen as discussed by the authors proposed a modification to Smith's (9) model, based on the fact that shockloaded iron (between 7 and II GPa) presents a substructure characterized by straight screw dislocations.