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Complete Guide to Using PolyUMod with COMSOL Multiphysics


Did you know that it is easy to use all the advanced non-linear viscoplastic material models in the PolyUMod library with COMSOL Multiphysics? In this article (and video), I will show how you can use the PolyUMod Bergstrom-Boyce (BB) model to simulate the tensile behavior of an ASTM D638 Type V dogbone-shaped specimen under cyclic tensile loading using COMSOL Multiphyics. The steps listed below summarize the key steps that may be unique when using a PolyUMod material model in COMSOL Multiphysics. The video at the bottom of this page is a complete step-by-step guide to using PolyUMod with COMSOL.

Step 1: Export Material Model from MCalibration

Export the PolyUMod material model into COMSOL csv-file format.

The contents of the exported file are shown below.

Step 2: Setup the Material Model in COMSOL Multiphysics

Within COMSOL Multiphysics, right-click on Materials, and select External Material. Then setup the PolyUMod material model as  indicated in the figure below. Note that the number of state variables (here 13) is specified in the file that was exported from MCalibration in Step 1.

Then copy the list of material parameters from the file that was exported from MCalibration in Step 1, and paste that list into the Value field (in red) below.

Step 3: Add The Material Model to the Solid Mechanics Node

Right-click on Solid Mechanics and Select Material Models > External Stress-Strain Relation. Then select the PolyUMod material model in the External material drop down list.

Step 4: Optional Solver Settings for PolyUMod for COMSOL

Here is a list of recommended solver settings when using a PolyUMod material model.

In the time-dependent solver, set the Steps taken by the solver to Strict.

In the Fully Coupled solver, set the Jacobian update to On every iteration.

That’s it. Now run the FE simulation and process the results. For more info, including all details, see the following movie.


More to explore

What Is A Material Model?

I often get asked to define the terms “Material Model” and “Material Parameter”. This short article tries to explain what these terms mean.

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