About Rigid Connections

A rigid connection locks the physical relationship—the distance and angle—between the selected faces, edge, or points.

A rigid connection has approximately the same effect as bonded contact, in that it essentially locks the two parts together and they will never move relative to one other. Bonded contact should be used when the two parts are very close to each another, while rigid connections should be used when the parts are farther apart.

You may want to use a rigid connection for several reasons:

To distribute loads on a model
To simulate end conditions; for example, modeling a rigid end plate
To simplify modeling of complex mechanical constraints or more complicated fastening mechanisms