For a Transient Structural analysis using a linked Modal system, the Options category includes the following properties:
- Include Residual Vector
This property is available for a Transient Structural Analysis Using Linked Modal Analysis System. When set to the application executes the RESVEC command and calculates or includes residual vectors. The default setting is . See the RESVEC command documentation in the Mechanical APDL Command Reference for additional information.
- On Demand Expansion
This property is available when you are performing a Transient Structural Analysis Using Linked Modal Analysis System. Options for this property include (default), , and . When set to , an additional read-only property, On Demand Expansion, displays. This property only displays for the option and the application determines the value for the property, either or . The application sets this property as when you request output controls or request fewer frequencies than the number of modes.
When the On Demand Expansion Option property is set to , either manually or from the setting, the application creates the result file optimally. That is, the application evaluates the results using the Modal solution data and calculates any other results “on demand.” This improves solution performance and reduces file size. In addition, the application automatically removes mode shape data from the result file as determined by the On Demand Mode Shape preference (see note below).
Furthermore, there are specific result types supported when this option is active:
Total and Directional Deformation
Total and Directional Acceleration
Total and Directional Velocity
Maximum, Middle and Minimum Principal Elastic Strain
Maximum Shear Elastic Strain
Elastic Strain Intensity
Normal Elastic Strain/Shear Elastic Strain
Equivalent Stress
Maximum, Middle and Minimum Principal Stress
Maximum Shear Stress
Stress Intensity
Normal Stress/Shear Stress
Force Reaction/Moment Reaction
Important:Force Reaction and Moment Reaction probes are only supported when scoped to a Boundary Condition.
The Moment Reaction probe is not supported on beam or shell bodies or when scoped to Remote Displacements.
Loading conditions applied to geometric entities that are scoped to a Reaction probe are not included in the probe's calculation.
You can change the default setting () of this property using the On Demand Expansion Option preference contained in the Options (Modal, Harmonic and Transient Mode Superposition) category of the Analysis Settings and Solution category of the Options dialog.
Also note that mode shape data is automatically removed from result files. You can change the setting of this process using the On Demand Mode Shapes preference, also contained under the Options (Modal, Harmonic and Transient Mode Superposition) category of the Analysis Settings and Solution category of the Options dialog.
- Mode Selection Method
This property displays when you are performing a Transient Structural Analysis Using Linked Modal Analysis System. This property enables you to select the modes for the mode expansion. Property options include:
(default): This option expands all the extracted modes from the modal analysis. All the modes participate in the mode-superposition transient dynamic analysis.
: When you select this option, the Significance Threshold property also displays. For the Significance Threshold property value, the application selects the modes that have a ratio for the Modal Effective Mass to the Total Mass that is greater than this value, in all directions, for expansion. That is, only the selected modes participate in the mode-superposition transient dynamic analysis. The application default is
0.001. This feature improves the performance of postprocessing the modal results and reduces the file size.
For more information, see the Mode Selection Based on Modal Effective Mass section of the Mechanical APDL Structural Analysis Guide.