Abstract
This paper describes a successful application of Magnetorheological (MR) grease to a shear type controllable damper. MR fluid is known as a kind of functional fluid which changes rheological property when external magnetic field is applied. However, there is a problem with the sedimentation of the dispersed particles. To prevent the sedimentation, MR grease has been developed. In this study, a shear type controllable damper using MR grease has been developed. Performance test has shown that the proposed damper has wide dynamic range of damping force despite its simple structure. The ratio of maximum damping force in on-state to that in off-state is approximately 30. In addition, the proposed damper is installed between first floor and second floor of a 3-story model structure. The excitation test has shown that the dynamic characteristic of the model structure can be dramatically changed by the proposed damper. This indicates that the response to forced displacement can be controlled by external current.
