An Experimental Study of MR Dampers for Seismic Protection

An Experimental Study of MR Dampers for Seismic Protection
S.J. Dyke,1 B.F. Spencer Jr.,2 M.K. Sain3 and J.D. Carlson4
Abstract
In this paper, the efficacy of magnetorheological (MR) dampers for seismic response reduction
is examined. To investigate the performance of the MR damper, a series of experiments was
conducted in which the MR damper is used in conjunction with a recently developed clipped-optimal
control strategy to control a three story test structure subjected to a one-dimensional ground
excitation. The ability of the MR damper to reduce both peak responses, in a series of earthquake
tests, and rms responses, in a series of broadband excitation tests is shown. Additionally, because
semi-active control systems are nonlinear, a variety of disturbance amplitudes are considered to
investigate the performance of this control sytstems over a variety of loading conditions. For each
case, the results for three clipped-optimal control designs are presented and compared to the performance
of two passive systems. The results indicate that the MR damper is quite effective for
structural response reduction over a wide class of seismic excitations.