Review the following requirements and conditions. Go to a section topic:
Order of Operations
The application performs the Solution Combination calculations in the following order of operations:
Component results for base cases (this may involve temporal interpolation, such as Time = 1.5)
Linear/SRSS combination on these component results.
Spatial interpolation (such as scoping to Paths, Surfaces, etc.).
Computed results (such as Equivalent Stress) from the combined component results.
These operations are generally not interchangeable or commutative.
Coordinate Systems
Based on the results you add under the Solution Combination object, you can specify a user-defined Coordinate System for the result. The default setting is . The combination is calculated for the result based on this Coordinate System setting.
Important: Random Vibration and Response Spectrum analysis results are always calculated using the Solution Coordinate System. You must consider this when combining these results with results using another Coordinate System.
Stress and Strain Results for Random Vibration and Response Spectrum
When you specify a Random Vibration or a Response Spectrum analysis as a base case in the Worksheet, only and results are available (in the Stress and Strain result drop-down menus) for combination.
Averaging
For results, when you set the Averaging property to Yes, the application always uses the entire body for the averaging, regardless of the specified scoping. That is, if you scope a result to an edge or element face and specify averaging, the application uses the entire body of the scoped entity.
Equivalent Strains
Equivalent strains (including elastic, thermal, plastic, creep, total, and total-plus-thermal equivalent strains) are read from the result file and used directly in the linear combination formulation. The components (X, Y, Z, XY, YZ, XZ) are not used. Therefore, using the equivalent strains from the result file may lead to unexpected (or possibly negative) values.
Note: This behavior only applies to Equivalent Strains. Other calculated results, such as Equivalent Stresses and Total Deformations, are calculated by first combining the components and then following the order of operations specified above.
User Defined Results
The Solution Combination feature supports the use of User Defined Results to query result file data that is not exposed through customary results. See the User Defined Results for the Mechanical APDL Solver section for additional information.
User-defined results can perform basic mathematical operations; however, this option cannot reference another solved result that uses the same Identifier.
Important: The User Defined Result under the Solution Combination object follows an order of operations different from customary (non-user-defined) results. Therefore, if you query a result, such as SEQV, that is also available as a customary result, you may observe slight differences between the two.
Note: Note the following for a User Defined Result included under the Solution Combination object:
The application does not support the Display Option property, it is a read-only property set to Average. Furthermore, the Output Unit property is not available, therefore, results display an Average quantity instead of a Total.
Any mathematical operations specified in the Expression property apply to the individual base cases only, not the combined result.
Update Project
The Update Project option on the Workbench Project Schematic does not solve a Solution Combination.