How to Use the PolyUMod Library with Ansys LS-DYNA in Workbench

Introduction

In this article I will show how you can use a PolyUMod material model with Ansys LS-DYNA in Workbench. The procedure is very straigforward, the (perhaps) only step is that you need to copy the PolyUMod versions of LS-DYNA to the Ansys installation directory. All the details are given below.

Step 1: Create an LS-DYNA FE Model in WB

Create the FE model as you usually do in Workbench.

Step 2: Use MCalibration to Create a Material Model

Create a material model using MCalibration. In this example I’m using the PolyUMod Bergstrom-Boyce model.

Step 3: Export the Material Model

Export the material model to LS-DYNA format.

				
					*MAT_USER_DEFINED_MATERIAL_MODELS
$# -- MCalibration defined material model -- start
$# Units: [length]=meter, [force]=Newton, [time]=seconds, [temperature]=Centigrade
$# Material Model: PolyUMod-Bergstrom-Boyce
$# Calibration file name: Untitled
$#     mid        ro        mt       lmc       nhv    iortho     ibulk        ig
         1     1e-09        45        25        28         0        14        13
$#   ivect     ifail        it    ihyper      ieos      lmca
         0         1         1         1         0         0
$#      MM       ODE       JAC      ERRM    TWOD_S      verb     VTIME     VELEM
         4         0         0         0         0         1         0         0
$#    VINT    ORIENT     NPROP     NHIST       GMU    GKAPPA     FAILT     FAILV
         0         0        25        28         8      5000         0         0
$#      mu   lambdaL     kappa         s        xi         C   tauBase         m
         2       3.5       500         3      0.05      -0.5       0.5         8
$#  tauCut
      0.01
$# -- MCalibration defined material model -- end

Step 4: Specify the Material Model in Mechanical

Paste in the material model as a command snippet for the relevant part(s).

Step 5: Replace LS-DYNA Executables

This step only needs to be performed one time for each version of Ansys. First, copy the PolyUMod-provided custom LS-DYNA executables to the clipboard. There is one executable for single precision and one executable for double precision.

Then paste the PolyUMod provided LS-DYNA executables into the Ansys installation directory shown below. You may want to rename the existing files as follows before overwriting them with the PolyUMod enhanced versions. Rename lsdyna_dp.exe with lsdyna_dp.exe.ORIG, and lsdyna_sp.exe with lsdyna_sp.exe.ORIG.

Step 6: Run the FE simulation

Run the FE simulation as usual from within Mechanical. Make sure the Solution Information include the PolyUMod information lines. This proves that Ansys found the PolyUMod version of LS-DYNA.