Development of rolling pendulum type dynamic absorber using magnetic damping

Abstract

Purpose of this paper is to reduce the response of rocking vibration mode of vertically isolated equipment. The rocking vibration is the motion that the top of equipment vibrates as the fulcrum in a bottom end. According to the low vertical stiffness of vertically isolated equipment, the rocking vibration is largely excited by horizontal earthquake motion. In this paper, a dynamic absorber is developed in order to apply to the rocking vibration of the vertically isolated equipment. The proposed system is a rolling pendulum type dynamic absorber using magnetic damper, which is composed of circular rails, a rolling body including magnets and a conductor plate. The design method for the dynamic absorber and the evaluation method for vibration reduction effect are showed in this paper. The dynamic characteristics are also examined by vibration test. It is confirmed from the vibration tests using a rocking model apparatus that the proposed dynamic absorber is effective for rocking vibration reduction.

Keywords

• dynamic absorber
• forced vibration
• vibration control
• magnetic damping
• rolling pendulum
• vertical seismic isolation