A Study of an Arm-Type Damper with Two Links and Three Joints : Case in Which a Rotary Viscous Damper Is Used

In this paper, a new type of arm-type damper consisting of two links, two joints (universal joints with friction) and a hinge (a rotary oil damper) has been developed. The damper is able to suppress six modes of vibration of a machine, three in translational modes and three in rotational modes. The trial damper was made and the resisting force characteristics in the three translational directions were discussed theoretically and experimentally. The seismic responses of a three-degree-of-freedom system and the frequency response of a one-degree-of-freedom system, which consist of a mass and four coil springs and supported by the damper, were measured using a two-dimensional electro-hydraulic type shaking table. The experimental results are compared with the calculated ones, and the effects of vibration suppression of the damper are discussed.