Bushings
Including bushings in a Motion Analysis study is equivalent to adding
a flexible mate. You can think of a bushing as a spring and damper system
containing a little bit of slop.
The SolidWorks Motion solver treats parts as infinitely stiff.
Consequently, you can place only one constraint (mate) restricting a specific
degree
of freedom on a part. In situations where more than one constraint
restricts a specific degree of freedom, all additional constraints are
redundant.
You can use bushings
instead of mates and set the stiffness to constrain the motion along the
direction of a particular degree of freedom. The load on each bushing
is a function of the stiffness value.
Using bushings to represent mates and part stiffness, you can incorporate
stiffness in Motion Analysis studies. The more accurately you know the
stiffness, the better your results.