Boundary Change Assignment to Load Cases/Analyses

Different load (analysis) cases can retain separate boundary conditions within a model.  Even in the case where static analysis and dynamic analysis are associated with different boundary conditions, the two analyses can be carried out within a same model without having to make two different model files.

Analysis procedure for assigning different boundary conditions to Load Cases/Analyses is as follows:

1. Define as many Boundary Groups as required for different load cases or analyses, in Model>Group>Define Boundary Group.

2. Define Boundary Conditions and Load Cases.

3. Apply Loads.

4. Assign different Boundary Groups to Load Cases/Analyses using "Boundary Change Assignment to Load Cases/Analyses".

5. Perform analysis.

6. Review analysis results.

From the Main Menu select Analysis >  Analysis Control >  Boundary Change Assignment to Load Cases/Analyses.

Data Selection

The types of defined boundary conditions, which can be applied to different load cases, are listed.

Boundary Group Combination

Boundary Group List

Boundary condition groups selected in Data Selection to the left are listed.
If Filter Boundary Group at the bottom is not checked, all the boundary condition groups are listed.

Name

Name a Boundary group combination, which will be applied to a load case.  Having named a Boundary group combination, select desired boundary groups from Boundary Group List, and click to create a Boundary group combination.  Multiple Boundary group combinations are thus created, each of which is assigned to each load case.  A separate analysis can be then performed for each load case with its own Boundary group combination.

Load Cases & Analyses

Load combinations of static analysis and analysis types are listed.  In the case of static analysis, click to expand the table and list the static load cases defined by the user.

Boundary Group Combination

Select a Boundary group combination (by clicking in the right end of the entry field) to be applied to the static load case or analysis type to the left.  If Unchanged is selected in a construction stage analysis, the boundary condition corresponding to the final construction stage is used. If Unchanged is selected in an analysis without construction stages, all the entered boundary conditions are used.

Constrain DOF associated with Specified Displacements/Settlements by Boundary Group Combinations

In a Specified Displacements or Settlements analysis, the degrees of freedom at the corresponding nodes are internally constrained and treated as supports, and forced displacements are assigned.  If this option is selected (checked on), the internal DOF constraints are included in only the boundary group combination corresponding to the Specified Displacements/Settlements.

Click to remove all the data.  

Note
The Boundary Change Assignment, as the name suggest only changes specific boundaries as required by the user.  By default, all the boundaries which are assigned/active in Post CS are applicable for the structure.  The workflow for this feature is as below:

1.       Under “Data Selection”, select the boundary type which needs to be changed.

2.       Under “Boundary Group List”, select the boundary groups which are to stay active.

3.       Type the Boundary Group Combination Name and click Add/Replace.

4.       Now select the “Boundary Group Combination” for relevant static load case or analysis type.

If certain boundary type is not selected under “Data Selection”, then all the boundary of that type are applied to the structure by default.