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, so you can place only one constraint (mate) restricting a specific degree of freedom on a part. When 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.

Replacing Mates with Bushings

To attempt to remove redundancies introduced by mates, you can try to replace a mate with a bushing.

After trying the other redundancy removal methods, you can replace a redundant mate with a bushing. Replacing mates with bushings increases the motion calculation time, but is simpler than defining mate relationships using mate primitives.

To replace a mate with a bushing:

  1. Expand the Mates folder:
    • Expand mates in the FeatureManager design tree to replace a model mate with a bushing.
    • Expand the mates in the MotionManager tree to replace a local motion-study specific mate with a bushing.
  2. Right-click the mate and click Edit Feature fm_edit_feature.gif.
  3. In the PropertyManager, select the Analysis tab.
  4. Select Bushing, set the parameters, and click PM_OK.gif.
    The Update Initial Animation State dialog box might appear. You can click Yes or No to dismiss it.
  5. Click close.gif to close the PropertyManager.
  6. Click Calculate (MotionManager toolbar) to test the mate redundancies.
    The updated mate icon includes a bushing matetobushing.png.

Bushing Parameters

For all bushings that are used to replace redundant mates, you can assign the stiffness and damping in Bushing Parameters.

To open this dialog box:

Click Bushing Parameters from Motion Analysis in the Motion Studies Properties PropertyManager.

Stiffness Enter values for translational and rotational stiffness.
Damping Enter values for translational and rotational damping.