Pretension Manager

Use the Pretension Manager tool to create and edit 1D and 3D pretension bolt loads and bolt sections for the OptiStruct solver.

From the Analyze ribbon, click the Bolt Pretension tool.
Figure 1.


This tool is only available when the OptiStruct user profile is loaded.

For details on how the pretensioned bolt analysis works inside of OptiStruct, refer to Pretensioned Bolt Analysis in the OptiStruct online help.

Pretension Manager Dialog

The Pretension Manager uses a table format to display all the bolt pretension loads in the model. Each row represents a pretension load in the model, and each column represents the following:
Table 1.
Column Description Related OptiStruct Card(s)
Bolt Type Displays the type of bolt the load is applied to. Can be 1D or 3D. PRETENS
Bolt Id Displays the identification number of the Bolt Pretension section the load is applied to. PRETENS
EID/SURFID Displays the Element (1D) or Surface (3D) identification number where the Bolt Pretension section is located. PTFORCE, PTADJST
Load Type Allows you to review and edit the type of pretension load, by selecting one of the following options from the pull-down menu:
  • Force
  • Adjustment

Use the Ctrl key to select and edit this field in multiple rows at once.

Click OK or Apply to update the load types in the model. Click Cancel to exit the Pretension Manager without saving any changes.

 PTFORCE, PTADJST
Allows you to review and edit the Load Collector where the pretension load is organized in HyperMesh, by selecting one of the following options from the pull-down menu:
Select Existing
Takes you to the Load Collector Selector panel.
Create New
Automatically creates a new Load Collector with the name prefix PRETENS_* to organize the load into.

Use the Control key to select and edit this field in multiple rows at once.

Click OK or Apply to update the load types in the model. Click Cancel to exit the Pretension Manager without saving any changes.

 PTFORCE, PTADJST
Load Id Displays the HyperMesh internal identification number of the individual loads.
Load Magnitude Allows you to review and edit the pretension load magnitude.

Use the Control key to select and edit this field in multiple rows at once. Enter a new value and press Enter to apply the changes to all of the selected rows.

Click OK or Apply to update the load types in the model. Click Cancel to exit the Pretension Manager without saving any changes.

 PTFORCE, PTADJST
Orientation (Optional) Allows you to review and edit the determination type of the normal direction of the bolt pretension section, by selecting one of the following options from the pull-down menu:
Blank
Solver default
AUTO
GRIDS
Takes you to a G1,G2,G3 node selection dialog.
VECTOR
Takes you to the Direction Selector panel.
CID
Takes you to the System Selector panel.
The Orientation type value will be updated in the model immediately after editing the selection.
Output DOF ID (Optional) Allows you to review and edit the SPOINT that contains the pretension deformation and load, by selecting one of the following options from the pull-down menu:
Select Existing
Takes you to the Node Selector panel.
Create New
Automatically creates a new SPOINT and assigns it to the bolt pretension section.

Use the Control key to select and edit this field in multiple rows at once.

The Output DOF ID value will be updated in the model immediately after editing selection.

 PRETENS
The Pretension Manager dialog contains the following buttons:
Table 2.
Button Description
Add 1D Bolts Allows you to create one or more 1D Bolt Pretension sections.
To add a 1D Bolt Pretension section:
  1. Click Add 1D Bolts.

    The Element Selector panel opens.

  2. Select one or more beam, bar or rod elements.
  3. Click Select.
  4. Click Proceed.

    The individual 1D Bolt Pretension sections will be created for each selected element.
Add 3D Bolts Allows you to create one or more 3D Bolt Pretension Sections. Two options are available when you click Add 3D Bolts:
  • Choose Select Existing Surface to open the Contact Surface Selector panel, where you can select existing surfaces. Once you click Select and Proceed, the individual 3D bolt Pretension Sections will be created for each selected contact surface.
  • Choose Create New Surface to open the Contact Surface Create (solid faces) panel, where you need to select elements and face nodes to create the surface for the bolt pretension section, as depicted in the images below.
    Step 1:
    Select elements on one side of the bolt:
    Figure 2.


    Step 2:
    Select nodes on the section face:
    Figure 3.


When you are using the Create New Surface option, a default name will be automatically assigned in the panel using the prefix PRETENS_* and the appropriate card image. Once you click Create and Return, you will be brought back to the Pretension Manager. The Pretension Manager will now display a 3D Bolt Pretension section for the new contact surface.
Add Load Allows you to add a new pretension load to an existing Bolt Pretension section.
To add a new pretension load to an existing
  1. Click the checkboxes in the first column for the Bolt Pretension section that you want to add a new load to.
  2. Click Add Load to add the new load to the selected Bolt Pretension section.

    The new load will be added directly below the section you wanted to add the new load to, and organized using a hierarchical tree-like display fashion.

Bolt Pretension section:
Example
The model below has four Bolt Pretension sections with IDs 1, 2, 3 and 4, and the pretension Force loads of 9500, 10000, 11500, and 9000 are applied to them, respectively.
Figure 4.


An additional pretension Adjustment load of 0.1 needs to be applied to Bolt Sections 3 and 4 only. To do this, you must select the checkboxes for sections 3 and 4 (as shown above), and then click Add Load. One additional pretension load is added below each of the selected bolt sections.
Figure 5.


Looking at the left side of the table, it is easy to see that there are only four Pretension Bolt sections in the model, however, some of them have more than one pretension load applied to them.

In this example, the Force loads on all bolts are organized into Load Collector PRETENS_1, while the Adjustment loads on Bolts 3 and 4 are organized into a different Load Collector PRETENS_2, which allows them to be used in a different Load Step if desired.
Delete Deletes the selected bolt pretension sections and/or pretension loads.
To delete selected bolt pretensions section:
  1. Click the checkboxes in the first column for the rows you wish to delete.
  2. Click Delete.

When a Bolt Pretension section has more than one load applied to it, deleting the bolt section at the top level will automatically delete all the loads applied to it. On the other hand, deleting single additional loads will only remove the selected loads.
Review Allows you to graphically review the Element/Surface, Load, and SPOINT assigned to the selected Bolt Pretension section. This button also displays more detailed information about the selected Bolt Pretension section's Orientation.
To review a Bolt Pretension selection:
  1. Click checkboxes in the first column for the Bolt Pretension section you wish you review.
  2. Click Review.

    The Review Pretension dialog opens.

  3. Click OK in the Review Pretension dialog to return to the Pretension Manager dialog.
Select All Select all rows in the table.
Select None Deselect all rows in the table.
Select Reverse Reverses row selection in the table.
View Controls the Pretension Manager table's view organization mode. There are two options available from the pull-down menu:
  • Choose By Bolt (default) to apply multiple loads to the same Pretension Bolt section are displayed directly below it, organized using a hierarchical tree-like display structure.
    Figure 6.


  • Choose All to apply multiple loads to the same Pretension Bolt section are displayed directly below it, using a flat display structure with no hierarchical organization. The Bolt Pretension section's Type and ID are displayed for all pretension loads in the model.
    Figure 7.