Quasicontinuum Method Distribution version 1.3 (February 2007) Download

The Quasicontinuum method is a mixed continuum and atomistic approach for simulating the mechanical response of polycrystalline materials at zero temperature. The method reproduces the results of standard Lattice Statics techniques at a fraction of the computational cost. The method was originally developed as part of the Ph.D. work of Ellad Tadmor at Brown University under the advisement of Michael Ortiz and Rob Phillips and since then has been expanded and extended by a number of researchers. Please see the overview section for details. A recent review of the quasicontinuum method discussing its theory and applications has been completed by Ron Miller and Ellad Tadmor. The review is published in the Journal of Computer-Aided Materials Design (vol. 9, 203-239, 2002). JCAMD has kindly provided a reprint of the review (1 Mb) which may be downloaded from here.

The version of the code offered here is a complete implementation, but is limited to plane strain conditions (two dimensional configurations with periodic boundary conditions in the out-of-plane direction) and simple Bravais lattices (i.e. single-atom basis materials). The code is designed to work with empirical EAM interatomic potentials stored in the ParaDyn (DYNAMO) format.

Features:

  • Macro programming language that allows the user to custom design a simulation algorithm
  • Adaptive meshing
  • Conjugate Gradient (CG) and Newton-Raphson (NR) solvers
  • Plot generation in Tecplot format

The code is written in Fortran 90 and is self-contained. It has been run under Unix/Linux, Apple OS X and Microsoft Windows XP using the following compilers:

  • Absoft Fortran 90/95 Compiler
  • GNU Fortran (gfortran) Compiler
  • G95 Fortran Compiler
  • IBM XL Fortran Compiler
  • Intel Fortran Compiler
  • NAGWare Fortran 95 compiler
  • PathScale Compiler Suite
  • Portland Group Inc. PGF95 Fortran 90/95 Compiler
  • Silicon Graphics MIPSpro Fortran 90
  • Sun Forte Developer Fortran 95
A convenient makefile architecture is supplied making it easy to compile and run the code on Unix/Linux/OS X platforms. Porting to Windows machines should be straightforward but is not supported. See the QC Tutorial Guide for information on making and running the code.

The code was written primarily by

  • Ron Miller, Carleton University
  • David Rodney, Institut National Polytechnique de Grenoble
  • Vijay Shenoy, Indian Institute of Science, Bangalore
  • Ellad Tadmor, Technion - Israel Institute of Technology
with contributions from Marcel Arndt, School of Mathematics, University of Minnesota.

The QC program includes code from the following open-source packages:

  • ParaDyn (DYNAMO), Molecular Dynamics program written by Stephen Foiles and Murray Daw at Sandia National Laboratories.
  • CONTRI, Constrained Delaunay triangulation routine written by Scott Sloan at the University of Newcastle.
  • FEAP, Finite Element Analysis Program which appears in the back of the book "The Finite Element Method" by O.C. Zienkiewicz.

Revision history: ( Click for a detailed list of revision changes)

  • 1.0 Original release (February 2003)
  • 1.01 Bug corrections, support for Portland Group compiler (August 2003)
  • 1.1 Bug corrections, support for multiple meshed domains, significant code speed-up, improved error handling, support for Intel Fortan Compiler (May 2004)
  • 1.2 Bug corrections, improved reliability for polycrystalline simulations, improved mesh adaption, improved input and output, code optimization (February 2005)
  • 1.3 Bug corrections, improved portability (code largely rewritten to conform to the Fortran 90 standard), improved makefile system, code optimized and memory usage reduced, new user capabilities, expanded Reference Manual and Tutorial Guide (May 2007)

This code is offered as a public service to help to promote QC-related research. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. A great deal of effort has gone into cleaning up the code (which like most research codes was a big mess) and debugging it. Despite this, the code almost surely contains additional bugs. Use the code as a jumping off point for your own research.

WE WILL NOT BE ABLE TO OFFER SUPPORT OR TO ASSIST YOU WITH DEBUGGING. However, an on-line discussion forum has been set up to allow users to assist each other and to ask questions. Please see the contact section for details.

The download package includes:

  • Quasicontinuum source code written in Fortran 90.
  • Documentation.
  • Three example test cases:
    - Grain boundary shear showing a how a shear stress applied to an aluminum bi-crystal results in grain boundary motion.
    - Nanoindentation in aluminum showing dislocation nucleation beneath a rigid flat punch.
    - Friction at the nano-scale involving the sliding contact of two nano-asperities.
  • EAM potentials

You can start by reading the documentation (the QC Tutorial Guide is a good place to start for new users):


QC Tutorial Guide version 1.3 (May 2007)

PDF format
QC Reference Manual version 1.3 (May 2007)

PDF format


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Download the complete QC package (including documentation) after filling out a short form:



Download QC Package version 1.3 (May 2007)