ABAQUS/CAE User's Manual


9.9.1 Adding unsupported keywords to your ABAQUS/CAE model

ABAQUS/CAE uses your model definition to generate ABAQUS/Standard or ABAQUS/Explicit keywords and data that are placed in an input file when you submit the analysis job. Currently ABAQUS/CAE may not support ABAQUS/Standard or ABAQUS/Explicit functionality that you might like to include in your model. If that is the case, you may be able to add the functionality using the Keywords Editor. Select ModelEdit Keywordsmodel _name from the main menu bar to start the Keywords Editor.

To use the Keywords Editor, you should be familiar with the syntax of ABAQUS/Standard or ABAQUS/Explicit keywords and data. For example, the Interaction module does not allow you to impose constraints between different degrees of freedom of the model using multi-point constraints. To impose multi-point constraints, you can use the Keywords Editor to add the *MPC keyword to the model. Similarly, you can use the Keywords Editor to select an element type that is not supported by ABAQUS/CAE.

When you submit the model for analysis in the Job module, ABAQUS/CAE incorporates changes you made using the Keywords Editor in the input file that is submitted for analysis. Keywords that you add to your model using the Keywords Editor persist even after you modify or regenerate the model using ABAQUS/CAE, because ABAQUS/CAE stores the contents of the Keywords Editor along with the model definition in the model database. As a result, the contents of the input file may not be valid (for example, if you added keywords that refer to steps that you subsequently deleted), and the analysis may fail.

Warning:  If you used the Keywords Editor to edit the original model, ABAQUS/CAE ignores those changes when you restart the analysis. For more information, see “Rules governing a restart analysis,” Section 18.4.3.

ABAQUS/CAE indents some of the keywords in the Keywords Editor to make the input file easier to read on the screen. The keywords that are indented can never appear on their own in the input file and must always be used in conjunction with another keyword. The indentation that you see in the Keywords Editor is not included in the input file that is generated by ABAQUS/CAE.

The Keywords Editor does not allow you to edit the geometry of your model; you must use ABAQUS/CAE to make geometry changes. Therefore, the Keywords Editor is available only after you have generated the mesh. If the input file generated by ABAQUS/CAE is exceptionally long, the Keywords Editor displays the input file one buffer at a time. You can use the scroll bar to scroll through each buffer and the buttons at the bottom of the editor to display the next or previous buffer.

If you use the Keywords Editor to modify the input file and then use ABAQUS/CAE to modify the model, ABAQUS/CAE merges the changes into the input file. If a conflict arises during the merge, ABAQUS/CAE issues a warning message. You can then use a text editor to modify the input file and manually submit the job for analysis. For more information, see “Writing the input file only,” Section 18.5.2, and “Execution procedure for ABAQUS/Standard and ABAQUS/Explicit,” Section 3.2.2 of the ABAQUS Analysis User's Manual.

It is recommended that you not edit keywords that are supported by ABAQUS/CAE; for example, you should use the Property module, not the Keywords Editor, to change the properties of a material. This approach maintains consistency between directly supported aspects of a model and those added by the Keywords Editor. If you do edit a keyword using the Keywords Editor and then use ABAQUS/CAE to make a change to your model that refers to the same keyword, a conflict will occur. (For more information, see “Resolving conflicts in the input file,” Section 9.9.2.)

You can review the keywords supported by ABAQUS/CAE by selecting HelpKeyword Browser from the main menu bar.

To edit the model's keywords:

  1. From the main menu bar, select ModelEdit Keywordsmodel _name.

    The Keywords Editor appears and displays the keywords associated with the model you select.

    Note:  The keywords are available to be edited only after you have generated a mesh.

  2. Each keyword in the input file is displayed in its own block. Buttons in the lower left corner of the Keywords Editor allow you to do the following:

    Add After

    Add an empty block of text below the selected block; text that you add to a new block appears in blue.

    Remove

    Remove the selected block of text that was added using the Keywords Editor. You cannot remove a block generated by ABAQUS/CAE.

    Discard Edits

    Discard the changes you made to a block generated by ABAQUS/CAE during the most recent use of the Keywords Editor.

    Buffer x of y :

    Display the next and previous buffer of a large input file. Use the scroll bar to scroll within a buffer.

    In addition, you can click any block and edit the text inside. Cyan text indicates a block generated by ABAQUS/CAE that you edited.

  3. From the buttons across the bottom of the Keywords Editor, click OK to include your changes and to close the editor. Click Cancel to close the editor and to disregard your changes. Click Discard All Edits to keep the editor open and to remove all of the changes that you made to the input file.


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