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
Citations
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Journal ArticleDOI
Damage to Polystyrene Polymer Film by Shock Wave Induced Bubble Collapse.
TL;DR: It is observed that polymer molecules located in the jet vicinity undergo conformational extension in the direction perpendicular to the jet motion, while chain molecules in the rest of the film undergo compression, and damage to the film is sensitive to the strength of the shock wave.
Journal ArticleDOI
Onset of failure in argon by the effect of a shockwave: A molecular dynamics study
TL;DR: In this article, a simulation of a piston hitting a sample from one side of the simulation box, at speeds ranging from 1.2 to 1.3 times the speed of sound in solid argon at the chosen density, was performed.
Book ChapterDOI
Simulations of Hydrocarbon Polymers Related to Compression Experiments on Sandia’s Z Machine
TL;DR: In this article, a combination of first-principles simulations using density functional theory (DFT) and atomistic simulations using classical molecular dynamics has proven to effectively model different aspects of the system.
Dissertation
Atomistic modeling of the AL and Fe₂O₃ material system using classical molecular dynamics
Molecular dynamics simulations of detonation in defective explosive crystals
Timothy C. Germann,Brad Lee Holian,Peter S. Lomdahl,Andrew J. Heim,Niels Grønbech-Jensen,Jean-Bernard Maillet +5 more
TL;DR: Germann et al. as discussed by the authors performed large-scale molecular dynamics simulations using a reactive empirical bond-order (REBO) model potential to investigate the detonation process in condensed phase explosives at a microscopic scale.
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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.