Required Input File Keywords

Modify legacy input file keywords for use with new technologies.

If you are adapting a previously generated input file that contains cohesive elements for use with Helius PFA, there are specific keywords that are required. Here, these keywords are listed for reference. For a comprehensive discussion of these keywords, refer to the Use a Text Editor to Convert Pre-Existing Abaqus Input Files for Use with Helius PFA section of the Helius PFA User's Guide and the Abaqus Keywords Reference Manual.

The keywords *Depvar, *User Material, and *Material define the behavior of the Helius PFA cohesive material. For example, the following block of text defines the cohesive material for this tutorial.
```
*Material, name=Cohesive_Material
*Depvar
      9,
*User Material, constants=8
12.,9500.,1070.,1070.,  10.,  30.,  30., 0.01
```
For the cohesive section definition, *Cohesive Section, the response parameter must be set to Response = Traction Separation.
In the step definition, *Step, set Extrapolation = No.

Solution controls must be added to allow for optimal convergence as follows:

*Controls, reset
*Controls, parameters=time incrementation
1000, 1000, 1000, 1000, 1000, , 1000, , , 10,

In the element field output requests, *Element Output, state variables (SDV) must be requested to view the variables generated by Helius PFA.
In addition, the cohesive element type, *Element, must be COH2D4 or COH3D8.