72 巻 (2006) 716 号 p. 1056-1063
Magnetic damper has the advantages of a linear damping force, a non-contact mechanism and being good at hot and vacuum circumstances. However, its damping coefficient is not so large, so that it is necessary to use a force magnifying mechanism in order to obtain a large resisting force. When the damping force is magnified by a magnifying mechanism, the inertia force of a conductor plate is also magnified. This magnified inertia force exerts a bad influence on the effects of vibration suppression for a vibration system in high frequency range. In this paper, two types of vibration systems in which a magnetic damper was attached to a primary mass through a spring were considered in order to make the magnetic damper effective in wide frequency range. The optimum conditions of the damper and the elastic support were analyzed and the frequency responses of the vibration systems supported with the damper were calculated. The trial magnetic damper using a lever-type force magnifying mechanism was made and its resisting force characteristics were measured. The frequency responses and seismic responses of two types of vibration systems were measured using an electrohydraulic type shaking table. The experimental results were compared with the calculated results and the effects of vibration suppression of the magnetic damper and the elastic support were discussed.