The ability to create named selections in Ansys Workbench is a valuable feature that allows for the easy transfer of selections to ANSYS Mechanical or their use in creating specific features. Named selections can encompass a combination of 3D entities, including point feature points (PF points). To perform selections, navigate to the Apply/Cancel property called Geometry in the Details View of ANSYS DesignModeler.
Named selections play a crucial role in ANSYS Mechanical analyses, serving as important parameters. They enable the definition of selections on the geometry, which can then be used to set boundary conditions in ANSYS Mechanical, Fluent, and other interfaces. This tool proves highly beneficial for accurately defining boundary conditions across different interfaces in ANSYS.
Named Selections with Geometry
Many users are unaware of this feature’s existence, as it may not be immediately apparent. If you haven’t created any named selections in your model, the Named Selections Icon in the toolbar remains hidden until you click on the Model top branch within the tree structure.
To create named selections using geometry, follow these steps:
Click on the ‘Create Named Selection’ tab.
To generate named selections on ANSYS geometries, right-click on the model subtab of the geometry (indicated by the red arrow) and select the ‘Create Named Selection’ option (shown in the red box).
Assign a unique name to the Named Selection.
After clicking on ‘Create Named Selection’, choose a name that accurately reflects the intended boundary condition for this selection. For instance, if it will be used for CFD, give it a name like ‘wall’, etc.
The default selection includes the entire geometry.
By default, the entire geometry is selected within the Named Selection. However, you can further refine your selection by choosing specific geometric features such as edges, faces, or vertices that correspond to the desired boundary condition in ANSYS Mechanical.
Creating named selections is a straightforward process using geometric selection. However, it’s worth noting that you can also create named selections for nodes, faces, and vertices without clicking! To do this, simply switch to the worksheet view instead of the geometry view.
Named Selection with Worksheet
To create a Named selection using the worksheet, just click on the NS icon. This will add a Named selection Branch and a Named selection to that branch. In the details View for the Named selection, you’ll notice that the Scoping Method is set to Geometry Selection by default. Click on the Geometry Selection, and a drop-down menu will appear, offering you the option to use the Worksheet. Choose that option:
Now, you will see a new tab called Worksheet in your graphics window. Within that Worksheet, there will be a Generate button and a table. If the table appears too small and doesn’t show the whole table, don’t worry, there will be a scroll bar at the bottom to access the rest of the content.
This tool is quite clever. Essentially, you add rows to the table that perform actions on the geometry from top to bottom. In many cases, a single line is sufficient. However, for more complex selections, you can stack them up and create intricate conditions. After executing each line, the active set changes based on what is specified in that row. The final active set is what becomes the named selection.
Let’s take a closer look at the table and each column:
Action: This column is the most important one as it informs Workbench about the desired action to be taken in each step of applying the filter. Under the action column, you have the following options:
- Add: This adds the entities defined in the row to the active set.
- For the first row in the table, it creates a new set.
- For the second and subsequent rows, the value in the Type column must be the same for the selection to work.
- This operation is similar to a union in set theory.
- Remove: This removes the entities specified in the row from the set.
- Think of it as unselecting.
- Filter: This selects a subset from the active set.
- It’s similar to an intersection in set theory.
- This operation is like an AND operation, where the active set includes only the entities defined in the row.
- Invert: This selects everything that is not in the active set of the current active set type and makes it active.
- It’s similar to taking the complement in set theory.
- Convert: This selects all entities of the type specified in the Geometry Type column that are connected to the active set and makes them the new active set.
- It moves up or down in the topology tree by one step (vertex <-> Edge <-> Face <-> Body).
- When going up, it selects any entity attached to the current selection set.
- In APDL, this is represented by xSLx: LSLA, ASLL, KSLL, LSLK, etc.
Right now it only selects the standard geometry topology types:
Remember that you can only have one Geometry Type in the active set at a time.
This tells the program what filter you want to apply to select geometry. The table below shows the different criterion and what Geometry Type’s they apply to:
This is where you decide how you want to manage your selection. You have your usual if() type operators and the option to define a range. For ranges, you enter values in the Lower and Upper Bound columns, while for other cases, you use the Value column. Here are the available options:
- Not Equal
- Less Than
- Less than or Equal
- Greater Than
- Greater Than or Equal
The Range: Setting Boundaries
When you choose the Criterion as Range, you specify the desired range in the Lower Bound and Upper Bound columns.
Units: Customize to Your Preference
As with many features in Workbench, you can modify the units here to match your requirements, if needed.
The Value: Making the Selection Criteria Clear
In this section, you input the value you want to select (unless it’s a range). For Criterion = Size or Location X/Y/Z, enter a numerical value. For Criterion = Type, refer to the values provided in the table above. And if you’re working with Face Connections, simply input the number of faces.
Lower Bound, Upper Bound: Defining the Range
When you set the Criterion as Range, use the Lower Bound and Upper Bound columns to indicate the desired range.
Modifying Your Table: Making Changes as Needed
To edit a cell’s value, simply click on it. To delete a row, click on any cell within that row, right-click, and select delete. Similarly, to insert a new row above the currently selected row, follow the same steps.
Don’t Forget to Generate: Updating Your Selection
Remember to click the generate button! If you skip this step, your selection won’t update. Even if you see a green checkbox next to your named selection in the tree, it might not be up to date. Clicking generate or selecting the Named Selection branch and right-clicking -> Generate Named Selections is essential.
By understanding the selector and its various options, you can confidently manage and refine your selections according to your specific criteria.