Modeling ramp compression experiments using large-scale molecular dynamics simulation.

Mattsson, Thomas Kjell Rene ; Desjarlais, Michael Paul ; Grest, Gary Stephen ; Templeton, Jeremy Alan ; Thompson, Aidan Patrick ; Jones, Reese E. ; Zimmerman, Jonathan A. ; Baskes, Michael I. (University of California, San Diego) ; Winey, J. Michael (Washington State University) ; Gupta, Yogendra Mohan (Washington State University) ; Lane, J. Matthew D. ; Ditmire, Todd (University of Texas at Austin) ; Quevedo, Hernan J. (University of Texas at Austin)

Sandia National Laboratories

关键词: Compression;    Plasticity;    Interfaces;    Elasticity;    Simulation;   

DOI  :  10.2172/1030397
RP-ID  :  SAND2011-6845
RP-ID  :  AC04-94AL85000
RP-ID  :  1030397

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来源: UNT Digital Library

【 摘 要 】

Molecular dynamics simulation (MD) is an invaluable tool for studying problems sensitive to atomscale physics such as structural transitions, discontinuous interfaces, non-equilibrium dynamics, and elastic-plastic deformation. In order to apply this method to modeling of ramp-compression experiments, several challenges must be overcome: accuracy of interatomic potentials, length- and time-scales, and extraction of continuum quantities. We have completed a 3 year LDRD project with the goal of developing molecular dynamics simulation capabilities for modeling the response of materials to ramp compression. The techniques we have developed fall in to three categories (i) molecular dynamics methods (ii) interatomic potentials (iii) calculation of continuum variables. Highlights include the development of an accurate interatomic potential describing shock-melting of Beryllium, a scaling technique for modeling slow ramp compression experiments using fast ramp MD simulations, and a technique for extracting plastic strain from MD simulations. All of these methods have been implemented in Sandia's LAMMPS MD code, ensuring their widespread availability to dynamic materials research at Sandia and elsewhere.