Vibration control by interface dissipation in semi-active joints

Large space structures often consist of truss elements which are connected by bolted joints. The interface dissipation in these junctions turns out to be the major source of damping. For vibration suppression, the joints are designed such that the normal force in the frictional interface is controlled for improving damping performance. The normal contact is varied by active control using a bolt with a piezoelectric washer. A system consisting of two elastic beams connected by a single active joint is considered. The friction phenomena are described by a friction model with velocity dynamics. The effect of displacement- and velocity-induced friction dynamics is considered in the design of the control law. The result is a dynamic controller which prevents frictional energy, stored as potential energy in the bristles, from being returned into the system.