Semi-active damping device for vibration control of buildings using magnetorheological fluid

Abstract

This chapter proposes a new shear mode damping device using magnetorheological (MR) fluid. The proposed damping device consists of two 10mm thick steel plates placed parallel to each other with a gap of 15mm in between. This gap is filled with MR fluid. Another steel plate, which can slide freely between the two parallel plates, is immersed in the fluid to a depth of about 30mm. The width of the sliding plate in contact with the MR fluid is 50mm. The design of electromagnetic circuit requires the optimization of magnetic field energy in the fluid gap and minimization of the magnetic flux loss in other areas of the circuit. There should be adequate steel areas so as to keep the magnetic field intensity low. The electromagnetic circuit design and the configuration of the MR damping device have been verified using the finite element computer program, COSMOS/M. Results of the two-dimensional finite element analysis indicate that there are losses and nonuniform distribution of fluxes at junctions and boundaries, especially at the parallel steel plates.