Applying pretension to bolted and screwed connections allows a more complete
understanding of the behavior of a structure.
Often, these preloads are of a significant magnitude and can influence design decisions.
Typical examples are clamping structures, such as bearing housings or bicycle handlebars and
seat-posts. In engines, cylinder bore distortion can be a critical design requirement highly
influenced by the loads generated by the bolt down of the cylinder head.
Pretension can be enabled on a fastener or multiple fasteners by selecting them, enabling
pretension in the Property Editor, and entering a pretension force. This pretension is then
included as a load in all load cases. Figure 1. Enabling and defining pretension in the Property Editor
A load case with no other external loads will apply the pretension loads only. When running any
model that includes pretension, Inspire automatically creates and runs a
load case with only pretension loads. Figure 2. Results showing automatically generated load case: Subcase 1
Pretension Properties
Following is a list of pretension properties and the types of objects to which they
apply (indicated in parentheses).
Press F3 to open the Property Editor.
Use Enable (fasteners)
Select the checkbox to allow entry of a pretension force for
fasteners.
