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
Molecular dynamics simulations of shock loading of nearly fully dense granular Ni-Al composites.
TL;DR: The shock-induced premature melting of Al led to the mechanochemical effect and played a role in the shock- induced chemical reaction in the reactive metal system.
Journal ArticleDOI
Molecular dynamics simulation of nanostructure formation in copper foil under laser shock forming
TL;DR: In this article, the microstructure evolution of polycrystal copper under high strain rate loading is studied via the molecular dynamics simulation, and the formation of nanostructures in copper foil under laser shock forming is revealed.
Journal ArticleDOI
Elastic-Plastic Transition under Uniaxial Stress BCC Tantalum
Oscar Guerrero,Marcelo Marucho +1 more
TL;DR: In this article, the elastic-plastic transition underuniaxial stress in defect free body center cubic (BCC) Tantalum crystals was studied and it was shown that the nucleation of defects at the time scales of molecular dynamics in tantalum is due to dynamical instabilities (soft-phonons).
Journal ArticleDOI
Molecular dynamics modeling of nonlinear propagation of surface acoustic waves
TL;DR: In this article, a new computational setup suitable for the exploration of nonlinear effects in free propagation and dissipation of surface acoustic waves (SAWs) is developed based on the molecular dynamics (MD) simulation method.
Proceedings ArticleDOI
Enhanced densification, strength and molecular mechanisms in shock compressed porous silicon
TL;DR: In this article, it was shown that the final density of silicon under shock compression is anomalously enhanced by introducing voids in the initial uncompressed material, which is seen in a growing class of other similar materials.
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.