A current-flowing electromagnetic shunt damper for multi-mode vibration control of cantilever beams

Abstract

In this paper, a multi-mode electromagnetic shunt damper employing the current-flowing method is newly developed for the semi-active vibration control of flexible structures. The electromagnetic shunt damper, which is used for the electromagneto-mechanical coupling transduction between vibrating structures and the electrical shunt circuit, consists of a coil and a permanent magnet. The conducting coil is attached to the cantilever beams and the two ends of the coil are connected to the current-flowing shunt circuit for the reduction of vibration. For the analytical and experimental validation of the multi-mode electromagnetic shunt damper, the first two modes of the cantilever beam are semi-actively controlled. In light of the frequency responses, the vibration and damping characteristics of the flexible beams with the electromagnetic shunt damper are investigated with reference to changes in the circuit parameters. Also, the time responses of the integrated systems with an initial condition are experimentally examined for validation of the proposed damper. The effect of the magnetic intensity on the shunt damping is studied by varying the gap between the aluminum beam and the permanent magnet. The theoretical prediction of the frequency response of the electromagneto-mechanically coupled beams shows good agreement with the experimental results. The present results show that the current-flowing electromagnetic shunt damper can be successfully applied to reduce the multi-mode vibration of flexible structures.