Journal ArticleDOI
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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Molecular dynamics simulations of warm laser shock peening for monocrystalline nickel
TL;DR: In this paper , the micro-mechanism of single-crystal nickel by WLSP was investigated via molecular dynamics (MD) simulations, which revealed that certain slip systems, i.e., (1¯ 1¯1) [1¯1¯0], (11¯ 1µ) [110] and (111) [01¯1µ], are sequentially activated during WLPS.
Dissertation
Plasticity of metallic nanostructures : molecular dynamics simulations
TL;DR: In this article, the results from simulations of uniaxial strain of both bcc and fcc nanopillars are presented, and it is shown that the outcome of these simulations depend sensitively on the initial configurations of the systems and the means by which strain is implemented in the simulations can affect the simulation results.
Journal ArticleDOI
Exploring the boundary between atoms and the continuum by computers: a personal history
TL;DR: A personal account of the history of atomistic simulations of fluids (at the atomic or molecular level) can be found in this article, where the authors focus on the competing efforts to reach the boundary between atoms and the continuum.
Journal ArticleDOI
The Crystallization of Disordered Materials under Shock Is Governed by Their Network Topology.
TL;DR: In this paper , a topological constraint theory was adopted to study the nanoscale crystal nucleation process in shocked soda-lime silicate glass, and it was shown that the propensity of nucleation is governed by the connectivity of the atomic network.
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.
Journal ArticleDOI
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.