Nanoscale

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(Interatomic Potentials available online)
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* [[Fe-C | Modified Embedded Atom Method (MEAM) potential for Fe-C]]
 
* [[Fe-C | Modified Embedded Atom Method (MEAM) potential for Fe-C]]
 
* [[FeHe | Modified Embedded Atom Method (MEAM) potential for Fe-He]]
 
* [[FeHe | Modified Embedded Atom Method (MEAM) potential for Fe-He]]
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* [[FeCrHe | K-12 Project for Fe-Cr and Fe-He systems]]
  
 
Tungsten
 
Tungsten

Revision as of 04:14, 26 June 2012

MetalsCeramicsPolymersBiomaterialsGeomaterialsReferences


Overview

Tensile Loading of an Aluminum Single Crystal. Movie showing deformation of single crystal aluminum loaded in the <100> direction at a strain rate of 1010 s-1 and a temperature of 300 K.

The nanoscale material models are molecular dynamics codes and tools used to ascertain properties at the atomistic scale. These simulations generally use interatomic potentials, or force fields, developed using properties obtained from both electronic scale) calculations and experiments, and feed these results into higher scale models, such as dislocation dynamics at the microscale, or continuum models at the macroscale. To date, much of the research at the atomistic scale has focused on informing continuum models for multiscale modeling of metal and polymer material systems. This particular site contains production and research codes that have been developed both at CAVS and outside for performing and analyzing atomistic simulation results. The production codes have user's manuals and a theoretical manual and have been used in practice to solve complex atomistic problems at the nanoscale. The codes that are research codes have not enjoyed the wealth of application and might not have a user's manual or a theoretical manual. We caution the user that there is some risk in using the research version of the codes. Another resource for computational chemistry can be found at computational chemistry.

Tutorials

If you are just beginning with atomistic codes, we recommend that you familiarize yourself with LAMMPS, MATLAB (pre- and post-processing) and some of the visualization codes.

LAMMPS

This section includes brief tutorials for learning to use LAMMPS.

MATLAB

This section includes a brief tutorial for using MATLAB.

Visualization

Miscellaneous

Preprocessing & Postprocessing Codes

This section includes codes used for preprocessing and postprocessing atomistic results. This section can also include scripts used to generate initial structures for inclusion in molecular dynamics simulations. Additionally, this subsection will include examples of xyz coordinate files that can be used in conjunction with the LAMMPS read_data command to upload.

Material Models

Molecular Dynamics Codes

This section includes links to molecular dynamics codes. LAMMPS[1] (Large-scale Atomic/Molecular Massively Parallel Simulator) is commonly used for many molecular dynamics simulations related to metal and polymer systems at CAVS. LAMMPS' Fortran predecessor WARP can also be used for parallel molecular dynamics simulations. Last, DYNAMO is commonly used for MEAM (modified embedded atom method)[2] interatomic potential generation.

Interatomic Potentials available online

For more information on interatomic potential generation using electronic structure information, use the following links.

Visualization Codes

This section shows links to visualization packages used at the atomistic scale. Of these, AtomEye, Ensight, OVITO, and VMD are most frequently used at CAVS. AtomEye, OVITO, and VMD are open source codes.

Atomistic Research

This section includes interatomic potential information for atomistic simulations. Embedded atom method[3] potentials can be found at the NIST Interatomic Potential website. A number of modified embedded atom method[2] potentials have been developed here at CAVS for lightweight metals and steel research. Some published and ongoing interatomic potential work at CAVS includes

Metals

Polymer Atomistic Research. Movie showing deformation of an amorphous polyethylene structure with 20 chains of 1000 monomers length. The strain rate is 1010 s-1 and the temperature is 100 K[4][5].

Aluminum

Copper

Magnesium

Iron

Tungsten

Calcium

Ceramics

Polymers

An example of tensile deformation in amorphous polyethylene using a united atom method potential.

Biomaterials

Geomaterials

References

  1. S. Plimpton, "Fast Parallel Algorithms for Short-Range Molecular Dynamics," J. Comp. Phys., 117, 1-19 (1995).
  2. 2.0 2.1 Baskes, M.I. (1992). Modified embedded-atom potentials for cubic materials and impurities. Phys. Rev. B, 46, 2727 (http://link.aps.org/doi/10.1103/PhysRevB.46.2727).
  3. Murray S. Daw, Stephen M. Foiles, Michael I. Baskes,(1993) The embedded-atom method: a review of theory and applications, Materials Science Reports, Volume 9, Issues 7-8, Pages 251-310. (http://dx.doi.org/10.1016/0920-2307(93)90001-U).
  4. 4.0 4.1 Hossain, D., Tschopp, M.A., Ward, D.K., Bouvard, J.L., Wang, P., Horstemeyer, M.F., "Molecular dynamics simulations of deformation mechanisms of amorphous polyethylene," Polymer, 51 (2010) 6071-6083.
  5. 5.0 5.1 Tschopp, M.A., Ward, D.K., Bouvard, J.L., Horstemeyer, M.F., "Atomic Scale Deformation Mechanisms of Amorphous Polyethylene under Tensile Loading," TMS 2011 Conference Proceedings, accepted.
  6. 6.0 6.1 6.2 Tschopp, M. A., & McDowell, D.L. (2007). Structures and energies of Sigma3 asymmetric tilt grain boundaries in Cu and Al. Philosophical Magazine, 87, 3147-3173 (http://dx.doi.org/10.1080/14786430701455321).
  7. 7.0 7.1 7.2 Tschopp, M. A., & McDowell, D.L. (2007). Asymmetric tilt grain boundary structure and energy in copper and aluminum. Philosophical Magazine, 87, 3871-3892 (http://dx.doi.org/10.1016/j.commatsci.2010.02.003).
  8. Spearot, D.E., Tschopp, M.A., Jacob, K.I., McDowell, D.L., "Tensile strength of <100> and <110> tilt bicrystal copper interfaces," Acta Materialia 55 (2007) p. 705-714 (http://dx.doi.org/10.1016/j.actamat.2006.08.060).
  9. Tschopp, M.A., Spearot, D.E., McDowell, D.L., "Atomistic simulations of homogeneous dislocation nucleation in single crystal copper," Modelling and Simulation in Materials Science and Engineering 15 (2007) 693-709 (http://dx.doi.org/10.1088/0965-0393/15/7/001).
  10. 10.0 10.1 10.2 Tschopp, M.A., McDowell, D.L., "Influence of single crystal orientation on homogeneous dislocation nucleation under uniaxial loading," Journal of Mechanics and Physics of Solids 56 (2008) 1806-1830. (http://dx.doi.org/10.1016/j.jmps.2007.11.012).
  11. K. Solanki, M.F. Horstemeyer, M. I. Baskes, and H. Feng, Multiscale study of dynamic void collapse in single crystals, Mechanics of Materials Volume 37, Issues 2-3, February-March 2005, Pages 317-330 dx.doi.org/10.1016/j.mechmat.2003.08.014
  12. Tang, T., Kim, S., & Horstemeyer, M. (2010). Fatigue Crack Growth in Magnesium Single Crystals under Cyclic Loading: Molecular Dynamics Simulation. Computational Materials Science, 48, 426., 48, 426-439 (http://dx.doi.org/10.1080/14786430701255895).
  13. Barrett, C.D., El Kadiri, H., Tschopp, M.A. (2011). Breakdown of the Schmid Law in Homogenous and Heterogenous Nucleation Events of Slip and Twinning in Magnesium. Journal of Mechanics and Physics of Solids, in review.
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