A Study of a Dynamic Vibration Absorber Using Circular Arc Springs and Magnetic Damping

A new type of two-dimensional dynamic vibration absorber which has a simple construction and low height has developed. The dynamic absorber is composed of a mass, semicircular arc springs, rare-earth magnets and free bears, and is able to move in every horizontal direction. The dynamic absorber is suitable for suppressing the vibration of small structures, such as three-story wooden houses, due to an earthquake, a wind or a ground motion. The modal mass and stiffness were calculated, and the optimum condition of the dynamic absorber was calculated using the fixed points theory and the area under the acceleration curve. The trial dynamic absorber was made and its resisting force characteristics were discussed experimentally and theoretically. The trial dynamic absorber was attached to the third story of a 3-story building model, and the frequency and seismic responses of the building model were measured using a permanent magnet type vibration table. The experimental results were compared with the calculated results, and the effects of vibration suppression of the dynamic absorber and the propriety of the calculations were confirmed.