Multiple subcases in a part or assembly model are allowed. Any/all of them can be active at the same time.
Multiple subcases are essential to complete model definitions for Linear Buckling, Prestress Static, Prestress Normal Modes and Nonlinear Buckling analyses, and they are created by default.
As shown in the above figure, Subcase 1 (Initial Stress Case) has a constraint and a load, but Subcase 2 (Linear Buckling Case) does not have any loads, and it includes the same constraint. This type of definition is needed for a linear or nonlinear buckling analysis. The two subcases are created automatically when you set the analysis type.
See the page, Subcases for Different Analysis Types for more information.
Two different subcases can have the same constraints but a different load. This capability can be useful in a static analysis with multiple load cases on a part with constant constraints. Similarly, two different subcases can have the same loads but different constraint schemes.
Autodesk Nastran analyzes all of the subcases and calculates the results in a single analysis.
Right-click on any individual subcase to access the following context menu:
- Edit: This provides an alternative way to edit the content of the subcase. Loads and constraints can be selected from their respective area to be added to the subcase.
- Copy: Copies the selected subcase.
- Paste: Pastes the selected subcase.
- Rename: This allows you to rename the subcase.
- Activate: This toggle allows you to activate or deactivate the subcase.
- Delete: Deletes the selected subcase.
- SPC Summation: This command allows you to do a single point constraint (SPC) force and moment summation, but only if you request single point constraint output.