Which Basis Option Should I Use?
It depends on the answers to the following series of questions:
1. What program created the FES file?
If Adams was used to create the FES file, the basis of the modal coordinates should be orthonormalized. By definition, all modal information contained in the MNF is orthonormalized, so modal stress strain data in an FES file created from Adams will always be orthonormal. Thus, when choosing to create an FES file while exporting modal coordinates, the only valid option for basis is orthonormalized.
If a program other than Adams was used to create the FES file, the modal stress data in the FES file may not be orthonormalized, and the following question needs to be considered.
2. Did the FE program perform orthonormalization when the MNF was created?
If the answer to this question is yes, then the correct basis to use is still orthonormalized. If the orthonormalization was not performed by the FE program (for example, the ANSYS MNF interface does not support it), then specify the basis as unorthonormalized. If you don’t know the answer to this question, specify unknown for the basis and Adams Durability will output the modal coordinates to the basis that is compatible with the stresses from the FE program based on the information contained in the MNF.
Note: | If you select to export to an FES file later in this procedure, the Basis text ox will automatically change to Orthonormalized. |