Feasibility study of a tunable friction damper

A new design of friction damper is proposed and called the tunable friction damper. The design is proposed as an alternative to a conventional sliding mass-type friction damper, which is commonly used to reduce vibration in rotating systems. The design combines advantages of the friction damper, which dissipates energy via sliding friction, and the spring-mass-type vibration damper, which absorbs energy by its own vibration. The tunable damper is designed to work as a friction damper while the mass slips and as a vibration absorber while the mass sticks, during which the conventional friction damper ceases to function as a damper. The most important advantage of the design is that the damper can be tuned for a large reduction of the vibration in a narrow frequency range of choice while providing damping in a broad range of frequency as well. Despite its simple concept, design analysis of the system is difficult due to the nonlinear dynamics of the system. Numerical simulations are employed to demonstrate the feasibility of the concept, and to understand the roles of major design parameters. It is shown that proper sizing of the mass and the compliance of the damper allows the design to exploit benefits of both the friction damper and vibration absorber.