抄録
Magnetorheological (MR) fluids behave like a Bingham fluid having yield stress which can be rapidly changed in a reversible manner by applying magnetic field, being expected the innovative applications to industrial devices such as damper, valve, clutch and brake. In applications of MR fluid damper to seismic isolation and suppression technologies, one of serious problems is the sedimentation of dispersed particles in the MR fluid in the off-working state. In this research, "MR fluid porous composite" made of porous materials pregnant with MR fluid has been fabricated to solve this problem. And also, a seismic linear motion MR damper utilizing MR fluid porous composite has been designed and developed, which mainly consists of a ball screw and a rotary MR brake. The rotary MR brake has multi-disks between which the sheets of MR fluid porous composites are installed, and an electromagnet. The ball screw works to convert the linear motion (damping force) of the MR damper to the rotation (braking torque) of the MR brake with almost no transmission loss. The damping properties of the developed seismic MR damper were investigated experimentally to be found that the damping force of 20 kN is produced when applying an electric current of 0.5 A as designed.
