skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Plasticity induced by shock waves in nonequilibrium molecular-dynamics simulation

Abstract

Nonequilibrium molecular dynamics (NEMD) simulations of shock waves in single crystals have shown that, above a threshold strength, strongly shocked crystals deform in a very simple way. Rather than experiencing massive deformation, a simple slippage occurs at the shock front, relieving the peak shear stress, and leaving behind a stacking fault. Later calculations quantified the apparent threshold strength, namely the yield strength of the perfect crystal. Subsequently, pulsed x-ray experiments on shocked single crystals showed relative shifts in diffraction peaks, confirming the authors NEMD observations of stacking faults produced by shockwave passage. With the advent of massively parallel computers, the authors have been able to simulate shock waves in 10-million atom crystals with cross sectional dimensions of 100 x 100 fcc unit cells (compared to earlier 6 x 6 systems). They have seen that the increased cross-section allows the system to slip along all of the available {l_brace}111{r_brace} slip planes, in different places along the now non-planar shock front. These simulations conclusively eliminate the worry that the kind of slippage they have observed is somehow an artifact of transverse periodic boundary conditions. Moreover, they have introduced a piston face that is no longer perfectly flat, mimicking a line or surfacemore » inhomogeneity in the unshocked material, and show that for weaker shock waves (below the perfect crystal yield strength), stacking faults can be nucleated by preexisting extended defects.« less

Authors:
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Assistant Secretary for Human Resources and Administration, Washington, DC (United States)
OSTI Identifier:
654142
Report Number(s):
LA-UR-97-4337; CONF-970707-
ON: DE98004658; TRN: AHC2DT05%%230
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: Meeting of the topical group on shock compression of condensed matter of the American Physical Society, Amherst, MA (United States), 27 Jul - 1 Aug 1997; Other Information: PBD: Mar 1998
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; MOLECULAR DYNAMICS METHOD; SHOCK WAVES; MONOCRYSTALS; STACKING FAULTS; COMPUTERIZED SIMULATION; DEFORMATION; PLASTICITY; SLIP

Citation Formats

Holian, B L. Plasticity induced by shock waves in nonequilibrium molecular-dynamics simulation. United States: N. p., 1998. Web.
Holian, B L. Plasticity induced by shock waves in nonequilibrium molecular-dynamics simulation. United States.
Holian, B L. 1998. "Plasticity induced by shock waves in nonequilibrium molecular-dynamics simulation". United States. https://www.osti.gov/servlets/purl/654142.
@article{osti_654142,
title = {Plasticity induced by shock waves in nonequilibrium molecular-dynamics simulation},
author = {Holian, B L},
abstractNote = {Nonequilibrium molecular dynamics (NEMD) simulations of shock waves in single crystals have shown that, above a threshold strength, strongly shocked crystals deform in a very simple way. Rather than experiencing massive deformation, a simple slippage occurs at the shock front, relieving the peak shear stress, and leaving behind a stacking fault. Later calculations quantified the apparent threshold strength, namely the yield strength of the perfect crystal. Subsequently, pulsed x-ray experiments on shocked single crystals showed relative shifts in diffraction peaks, confirming the authors NEMD observations of stacking faults produced by shockwave passage. With the advent of massively parallel computers, the authors have been able to simulate shock waves in 10-million atom crystals with cross sectional dimensions of 100 x 100 fcc unit cells (compared to earlier 6 x 6 systems). They have seen that the increased cross-section allows the system to slip along all of the available {l_brace}111{r_brace} slip planes, in different places along the now non-planar shock front. These simulations conclusively eliminate the worry that the kind of slippage they have observed is somehow an artifact of transverse periodic boundary conditions. Moreover, they have introduced a piston face that is no longer perfectly flat, mimicking a line or surface inhomogeneity in the unshocked material, and show that for weaker shock waves (below the perfect crystal yield strength), stacking faults can be nucleated by preexisting extended defects.},
doi = {},
url = {https://www.osti.gov/biblio/654142}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Mar 01 00:00:00 EST 1998},
month = {Sun Mar 01 00:00:00 EST 1998}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share: