SOLIDWORKS Simulation – Modeled Bolt Preloads
Overview
SOLIDWORKS Simulation is capable of applying theoretical bolt connectors to holes of a model for
an FEA analysis but Simulation is also capable of simulating modeled bolts with applied preloads as
well.
Setup
In this setup two plates are modeled along with a bolt body and a nut body placed into the
position shown in Figure 1. No loads are being used in this example except for loads that will
represent the internal forces of the bolt/nut system at their threaded interface.
Figure 1: Cross sectional view of a two pl ate system with modeled bolt and nut.
Fixtures
A “Fixed” fixture definition is place on the edge of the bottom plate far from the bolt hole itself to
facilitate observing how the stress distribution propagates through the plates due to the bolt
preload as shown in Figure 2.
Figure 2: Fixture placement shown to be on the outside edge face of the bottom plate.
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Loads
The bolt has a downward axial force applied to it of 10 lbs (an arbitrary axial preload force value).
This force is applied specifically to a split line face that partitions off the shank of the bolt that is
contacting the nut and where internal forces of a preload would generate.
Figure 3: Bolt force applied to split line face.
The nut, likewise, has a force applied in the upward axial direction on the hole shank face (shown
in Figure 4). This force is also 10 lbs. In this way the bolt and nut both experience a force that will
cause a clamping action to plates placed between them.
Figure 4: Nut force applied to hole shank face.
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Contacts
In this example, as all bodies have been modeled with contacting faces, a global contact definition
of “No Penetration” is applied in the analysis. This will allow all bodies to slide against one another
as the solver converges to the equilibrium. Notably it will allow the nut to slide down the shank of
the bolt to the location of preload equilibrium.
Results
Once the analysis has been solved the resulting stress plot (shown in Figure 5) will reflect the
internal stresses of a bolt/nut system preloaded to 10 lbs. Additionally, the stress distribution of
the plates themselves around the hole will be less suseptible to form stress concentrations.
Figure 5: Stress plot showing internal stresses of a modeled bolt due to preload.
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