A decentralized response-dependent MR damper for controlling building structures excited by seismic load

In this study, a decentralized algorithm for operating a semiactive MR damper was presented. The frictional force of the MR damper was determined based on the assumed shape functions using the displacement and velocity of the damper piston itself. The seismic response control performance of the MR damper was numerically and experimentally evaluated and compared to that of the passively or semiactively operated MR damper. The results from numerical analysis of SDOF system indicated that passively operated MR damper to have an optimal frictional force less than about 30% of the base shear force provided the smallest displacement response spectrum over all the periods. The proposed MR damper showed the better performance in reducing the absolute acceleration with the larger frictional force than the passive one. Also, the results from a three-storey benchmark building indicated that the proposed decentralized MR damper provided control performance equivalent to or better than the performance shown by the semiactive MR damper using a centralized LQR algorithm. Finally, the effectiveness of the proposed MR damper was verified through experimental tests of a full-scale five-storey steel structure with the MR dampers.