Bolt Pre-Tension
Use the Bolt Pre-Tension node to define the pre-stress force in pre-tensioned bolts. It is available for 3D models only.
A default Bolt Selection subnode is automatically added. Use one such node to select each individual bolt. Additional Bolt Selection subnodes are available from the context menu (right-click the parent node) or from the Physics toolbar, Attributes menu.
The Bolt Pre-Tension node is only available with some COMSOL products (see http://www.comsol.com/products/specifications/).
Bolt Pre-Tension
Select a Pre-tension type — Pre-tension force (the default) or Pre-tension stress.
•
For Pre-tension force enter a value or expression for Fp, the pre-tension force in the bolt.
•
For Pre-tension stress enter a value or expression for σp, the pre-tension stress in the bolt. The pre-tension force is computed through multiplication by the actual area of each selected bolt.
•
Pre-tensioned Bolts in the Structural Mechanics Modeling chapter for an complete description of how to model pre-tensioned bolts.
•
Bolt Pre-Tension Study for information about the Bolt Pre-Tension study type.
Solver Suggestion
This section is present only in models created in versions prior to 5.3, in which the new Bolt Pre-Tension study type was introduced. The purpose is to maintain backwards compatibility for older models.
Select Solve in bolt pre-tension study only check box to make the bolt pre-tension degrees of freedom behave as in a version 5.3 model, that is being solved for only in a study step of the Bolt Pre-Tension type. By default, the check box is cleared, and then the bolt pre-tension degrees of freedom are solved for in any type of study step, unless you explicitly suppress that.
The settings of the Solve in bolt pre-tension study only check box only affects new study sequences being generated. Existing study sequences will keep the current state for the bolt pre-tension degrees of freedom.
Once you select the Solve in bolt pre-tension study only check box, the Solver Suggestion section will be hidden. Thus, it is not possible to clear the check box again. The degrees of freedom created under this Bolt Pre-Tension node from now on assumes the version 5.3 behavior.
Location in User Interface
Context Menus
 Solid Mechanics>Bolt Pre-Tension
Ribbon
Physics tab with Solid Mechanics selected in the Model Builder tree:
Global>Bolt Pre-Tension