Bolt Preload

The Bolt Preload condition in the Refine stage applies a pretension load to a cylindrical face -- typically to model a bolt under pretension. For example, you can use the bolt pretension to model a bolt which is holding together two bodies by applying a known value of clamp force, grip length adjustment, or torque (to simulate the tightening of a nut or bolt). In addition, in both Explore and Refine stages, you can assign a bolt preload to a bolt assignment. Bolt assignments are currently not supported for Named Selections or faceted bodies.

Note: Prior to defining a Bolt Preload in the Explore stage, ensure you have defined your bolt assignments in the Prepare tab. For more information on assigning bolts, see Bolts.

When a Bolt Preload condition is applied to a body, you must specify the bolt axial direction. When a Bolt Preload is applied to a cylinder face, the cylinder axis becomes the bolt axis direction. Any bodies that the bolt passes through will be bonded to it by default. If you wish to exclude them from being bonded, then select the faces of the body that the bolt passes through with the secondary selection.

Note: Diameter on Bolt Preload is ignored in the Refine stage when the preload is assigned to an idealized bolt. In addition, Bolt Preload parameterization is not supported. Bolt Preloads are ignored during Topology Optimization.

If you have multiple bolts with the same load value and axial direction, Discovery applies the same preload value to all bolts selected.

Note: When a bolt pretension load is applied to a model, Discovery automatically performs a two-step analysis to simulate bolt pretension and locking. In the first simulation step the bolt pretension load is applied. In the second simulation step the shortened grip length of the bolt is locked and the other structural loads are applied.

This section contains the following topics: