LS-Dyna User Sub Routing
Dennis Chen
James Kennedy
Dear Dennis,
Using the *USER_DEFINED features takes some effort and programming efforts.
*MAT_USER_DEFINED_MATERIAL_MODELS
These are Material Types 41 - 50. The user must provide a material subroutine. See also
Appendix A. This keyword input is used to define material properties for the subroutine.
Isotropic, anisotropic, thermal, and hyperelastic material models with failure can be handled.
http://ftp.lstc.com/anonymous/outgoing/jday/manuals/DRAFT_Vol_I.pdf
APPENDIX A: User-Defined Materials
GETTING STARTED WITH USER-DEFINED FEATURES
We begin with a general introduction to user-defined features. This section is valid for
any user-defined feature described in the remaining appendices and serves as a practical
guide to enable you to begin coding. We will specifically discuss the different methods
for linking your user-defined subroutines to LS-DYNA. For a comprehensive overview
of user-defined features and their applications, please refer to Erhart [2010], which can be
seen as a complement to the present text.
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See if this is of some help:
Keller, L. “How To - User Defined Material Models with LS-DYNA on Windows”, July, 2020.
Please see Appendix A User Defined Materials in the latest LS-DYNA User's Manual as a start:
http://ftp.lstc.com/anonymous/outgoing/jday/manuals/DRAFT_Vol_I.pdf
Some further examples and notes:
Huinen, W.L.J., "Validation and Extension of 3D Material Model for PVC-Foam", Master's Thesis,
Mechanics of Materials, Eindhoven University of Technology, Eindhoven, The Netherlands, June,
2009.
http://www.mate.tue.nl/mate/pdfs/10559.pdf
An, J., "Soil Behavior Under Blast Loading", Ph.D. Thesis, Civil Engineering, University of
Nebraska - Lincoln, Lincoln, Nebraska, December, 2010.
http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1013&context=civilengdiss
http://digitalcommons.unl.edu/civilengdiss/14/
Perhaps these presentations may be of some help (see Appendix C)
Babbepalli, P., “Implementation of Moisture Dependent Constitutive Model for Paperboard”,
Master’s Thesis, Department of Mechanical Engineering, KTH Royal Institute of Technology,
Stockholm, Sweden, October, 2020.
usrmat_LS-Dyna_Fortran
Basics to implement user-defined materials (usrmat, umat, utan) in LS-Dyna with Fortran
https://github.com/jfriedlein/usrmat_LS-Dyna_Fortran
Some notes developed by Nader Abedrabbo, while working on his Ph.D. thesis at Michigan State University:
http://sites.google.com/site/aenader/umat-workshop
http://sites.google.com/site/aenader/umat-workshop/umat-theory
http://sites.google.com/site/aenader/umat-workshop/umat-fortran
http://sites.google.com/site/aenader/umat-workshop/umat-implement
http://sites.google.com/site/aenader/umat-workshop/umat-verification
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user-defined equation of state
Liu, T., Zhang, X.-T., He, N.-B., Jia, G.-H., "Numerical Material Model for Composite Laminates in High-Velocity Impact Simulation", Latin American Journal of Solids and Structures, Vol. 14, No. 11, pp. 1912-1931, March, 2017.
http://www.lajss.org/index.php/LAJSS/article/download/3750/2430
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Sincerely,
James M. Kennedy
KBS2 Inc.
May 18, 2025
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