The program endures a rigorous verification testing plan before its release. You can be reasonably assured of obtaining good results when you exercise documented features using standard, recommended procedures. In some situations, however, you may need to employ nonstandard procedures or techniques that have not been or cannot be fully tested by Ansys, Inc. because of their very nature. (An example is employing user-programmable features.) Be aware that verifying the results in such cases is your responsibility.
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The results of nonstandard uses of the program cannot be predicted; therefore, Ansys, Inc.'s testing cannot fully cover such uses. Although Ansys, Inc. does not discourage nonstandard uses, you must exercise caution and use your engineering judgment when doing so. For example, if you program your own element and use it in an analysis, the results depend primarily on how well you programmed the element. In such cases, you must verify the results and ensure that other, standard areas of the program are not adversely affected.
Following is a partial list of nonstandard features and uses:
User-programmable features (UPFs) -- Writing your own user routines, linking them into the program executable, and using them in an analysis.
Reading an external file into the program (for example, a results file or a superelement file created by you or by another program).
High-risk capabilities such as the following:
Changing element real constants or section data during the solution phase in between load steps. Depending on the element type being used, the element may not properly use the updated real constant or section data values.
Disabling the cross-checking of the solid model with the finite element model (MODMSH,NOCHECK).
Disabling element shape-checking (SHPP,OFF).
Using undocumented features, such as an element option not documented in the Element Reference or a command argument not mentioned in the Command Reference. Undocumented features are, by definition, unsupported and unverified; use them with caution.
If the program can detect the use of a nonstandard feature, it may issue a warning to that effect.
Follow these guidelines when you need to use the program in a nonstandard manner:
Use your engineering judgment and carefully review the analysis results.
Do not assume that other, standard areas of the program are not affected. Run a few test problems to verify.
If you need to contact Ansys, Inc. Technical Support concerning an analysis involving nonstandard use of the program, be sure to mention the nature and extent of the nonstandard feature that you employed.
For detailed information on UPFs, see the Guide to User-Programmable Features in the Programmer's Reference.