Define, specify, and plot state variables

This procedure summarizes the requirements for calculating UMAT state variables by Simcenter Nastran and plotting them in the post-processor.

Define state variables (programmers)

1. Define the state variables in the source code of the Simcenter Nastran UMAT subroutine, and compile and link the subroutine.

2. Define the number of state variables for material model type "&umatModel1;" and/or "&umatModel2;" in the XML (.umatx) file. For example, the numStateVariables variable defines 12 state variables in the following XML snippet:         

Specify and plot state variables (users)

1. Set individual state variables and/or a range of variables in the Model 1 or 2 State Variable Output Requests group on the User Models - Simcenter Nastran page, when you configure a UMAT.You specify the variables in the following ways:Positive integers separated by commas, for example 1,2,3.Range of positive integers separated by a hyphen, for example 1-12.When you click Expand on a range of variables, the software displays the variables in comma separated format. When you click Collapse , the software displays any comma separated variables in range format.

2. In the Solution dialog box, on the Results Options page, specify whether Simcenter Nastran calculates the state variables and outputs them to the Simcenter Nastran .op2 file for post-processing:Right-click an active solution→Edit→Results Options page.Click the Edit button next to Structural Output Requests to modify the existing structural output request, or click Create Modeling Object to create a new structural output request.In the Structural Output Requests dialog box, click the State Variables option, and select the Enable STATVAR Request check box.

3. After a successful computation where Simcenter Nastran calls your proprietary Simcenter Nastran UMAT subroutine, the Post Processing navigator lists the State Variable [Material=...] - Element-Nodal result:Expand that result to display the state variable outputs.Each state variable starts with the uppercase letter V-.

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Define, specify, and plot state variables, Simcenter 3D 2021.1 Series

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