Experimental study on ball screw type magnetic friction damper: Semiactive control using electromagnet

This report deals with the fundamental behavior of friction dampers for piping systems installed in industrial facilities. Energy dissipating effect depends on sliding displacement and friction force. If the sliding motion increases, the effect of energy dissipation is expected to rise. In this report, a ball screw-type magnetic friction damper is proposed to adapt on piping systems. In order to increase the frictional sliding, this damper converts an axial motion to a rotating motion by a ball screw. Frictional behavior occurs between a rotation disk and a fixed disk on the frame of damper Friction force depends on the permanent magnets located on the fixed disk. The fundamental characteristics such as load-displacement curves, damping force at the ball bearing and inertia force of the rotation disk are obtained by experiments and a calculation model is made from the experimental data. The calculated responses are, then, compared with the results from the experiment. The calculation model is applied to a one-degree-of-freedom-system in order to investigate the response reduction effect of the system. An electromagnet is applied on the damper instead of the permanent. magnet to control friction force and the controlled behavior is evaluated.