Create an Input File and Run xStiff

Helius PFA uses a *User Material definition instead of a *Elastic definition to define a material in Abaqus. When a *User Material definition is used, Abaqus is unable to compute certain section parameters because the elastic constants necessary to compute these section parameters are not available. You must define these parameters for an analysis to run successfully.

Helius PFA comes with the command line program xStiff that reads an Abaqus input file and automatically computes and inserts all extraneous stiffness parameters required for reduced integration elements with Helius PFA materials. This auxiliary program significantly improves the speed and accuracy of the model building process.

Before we run xStiff, we need to generate an input file from Abaqus/CAE.

1. Switch to the Job module
2. Create a job (Job > Create) named Tutorial_6_UD_Abaqus
3. From the main toolbar, select Job > Write Input > Tutorial_6_UD_Abaqus
4. Open the Helius PFA Command Shell and change the directory to the location of the Tutorial_6_UD_Abaqus.inp file.

   Tip: Use Windows Explorer to navigate to your working directory and start typing Command Shell, then click Command Shell 2016.lnk when it appears. This will automatically open the Helius PFA Command Shell in the appropriate directory.

   

5. In the Command Shell, enter:

   >>xstf /i Tutorial_6_UD_Abaqus

6. xStiff will write a modified input file and rename it Tutorial_6_UD_Abaqus_xs.inp. Open the new file and note the addition of the *Hourglass Stiffness keyword.