You apply fixed restraints to the cylindrical faces where bolts are
inserted to attach the inner disk part to the axle shaft.
The faces that you apply fixed restraints to are preselected in the
brake rotor

FeatureManager
design
tree under .
-
In the Optimization study
tree, right-click Fixtures
and select Fixed Geometry
.
-
In the graphics area, expand the brake rotor
flyout FeatureManager design
tree. In the Selection Sets folder,
select fixture.
The six cylindrical faces of the bolt circular pattern
appear in
Faces, Edges, Vertices for
Fixture

.
-
Click
.