The damping of structural vibration by rotational slip in joints

Interfacial slip in joints is the major contributor to the inherent damping of most fabricated structures. By fastening joints tightly enough to prohibit translational slip, but not tightly enough to prohibit rotational slip (thereby making only a small sacrifice in static stiffness), it is shown, both experimentally and theoretically, that a useful increase in the inherent damping in a structure can be achieved, provided an optimum joint load is maintained. The analysis is simplified by using a general dynamic analysis computer program with a sub-program to model the friction joint.