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Title: Modeling shockwave deformation via molecular dynamics

Abstract

Molecular dynamics (MD), where the equations of motion of up to thousands of interacting atoms are solved on the computer, has proven to be a powerful tool for investigating a wide variety of nonequilibrium processes from the atomistic viewpoint. Simulations of shock waves in three-dimensional (3D) solids and fluids have shown conclusively that shear-stress relaxation is achieved through atomic rearrangement. In the case of fluids, the transverse motion is viscous, and the constitutive model of Navier-Stokes hydrodynamics has been shown to be accurate - even on the time and distance scales of MD experiments. For strong shocks in solids, the plastic flow that leads to shear-stress relaxation in MD is highly localized near the shock front, involving a slippage along close-packed planes. For shocks of intermediate strength, MD calculations exhibit an elastic precursor running out in front of the steady plastic wave, where slippage similar in character to that in the very strong shocks leads to shear-stress relaxation. An interesting correlation between the maximum shear stress and the Hugoniot pressure jump is observed for both 3D and fluid shockwave calculations, which may have some utility in modeling applications. At low shock strengths, the MD simulations show only elastic compression, withmore » no permanent transverse atomic strains. The result for perfect 3D crystals is also seen in calculations for 1D chains. It is speculated that, if it were practical, a very large MD system containing dislocations could be expected to exhibit more realistic plastic flow for weak shock waves, too.« less

Authors:
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
OSTI Identifier:
6197371
Report Number(s):
LA-UR-87-2367; CONF-870753-46
ON: DE87013157; TRN: 87-033207
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: 5. topical conference of the American Physical Society on shockwaves in condensed matter, Monterey, CA, USA, 20 Jul 1987; Other Information: Paper copy only, copy does not permit microfiche production
Country of Publication:
United States
Language:
English
Subject:
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; 36 MATERIALS SCIENCE; FLUIDS; SHOCK WAVES; COMPUTER CALCULATIONS; COMPUTERIZED SIMULATION; SOLIDS; DISLOCATIONS; EQUATIONS OF MOTION; IMPACT SHOCK; MOLECULAR MODELS; NAVIER-STOKES EQUATIONS; SHEAR PROPERTIES; STRESS RELAXATION; CRYSTAL DEFECTS; CRYSTAL STRUCTURE; DIFFERENTIAL EQUATIONS; EQUATIONS; LINE DEFECTS; MATHEMATICAL MODELS; MECHANICAL PROPERTIES; PARTIAL DIFFERENTIAL EQUATIONS; RELAXATION; SIMULATION; 990200* - Mathematics & Computers; 360603 - Materials- Properties

Citation Formats

Holian, B L. Modeling shockwave deformation via molecular dynamics. United States: N. p., 1987. Web.
Holian, B L. Modeling shockwave deformation via molecular dynamics. United States.
Holian, B L. Thu . "Modeling shockwave deformation via molecular dynamics". United States. https://www.osti.gov/servlets/purl/6197371.
@article{osti_6197371,
title = {Modeling shockwave deformation via molecular dynamics},
author = {Holian, B L},
abstractNote = {Molecular dynamics (MD), where the equations of motion of up to thousands of interacting atoms are solved on the computer, has proven to be a powerful tool for investigating a wide variety of nonequilibrium processes from the atomistic viewpoint. Simulations of shock waves in three-dimensional (3D) solids and fluids have shown conclusively that shear-stress relaxation is achieved through atomic rearrangement. In the case of fluids, the transverse motion is viscous, and the constitutive model of Navier-Stokes hydrodynamics has been shown to be accurate - even on the time and distance scales of MD experiments. For strong shocks in solids, the plastic flow that leads to shear-stress relaxation in MD is highly localized near the shock front, involving a slippage along close-packed planes. For shocks of intermediate strength, MD calculations exhibit an elastic precursor running out in front of the steady plastic wave, where slippage similar in character to that in the very strong shocks leads to shear-stress relaxation. An interesting correlation between the maximum shear stress and the Hugoniot pressure jump is observed for both 3D and fluid shockwave calculations, which may have some utility in modeling applications. At low shock strengths, the MD simulations show only elastic compression, with no permanent transverse atomic strains. The result for perfect 3D crystals is also seen in calculations for 1D chains. It is speculated that, if it were practical, a very large MD system containing dislocations could be expected to exhibit more realistic plastic flow for weak shock waves, too.},
doi = {},
url = {https://www.osti.gov/biblio/6197371}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1987},
month = {1}
}

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