Development of large capacity semi-active seismic damper using magneto-rheological fluid

In recent years, there has been increasing research in several industrial fields for development of semi-active vibration control devices. In particular devices using magneto-rheological (MR) fluid have been attracting great research interest because they can realize high. performance as capacity-variable dampers. MR fluids are controllable fluids that respond to applied magnetic fields. Applied magnetic fields drastically change the viscosity of MR fluids from an oily state to a semi-solid state. This paper describes a study on a large capacity device using an MR fluid, i.e., an MR damper This developed MR damper provides a maximum damping force of 300 kN. Various tests were carried out and the dynamic characteristics, force-displacement hysteresis loops and controllable forces were investigated. These tests verified that the MR damper provides a technology that enables effective semi-active control of large-scale structure systems, i.e., real buildings and civil engineering structures.