Hysteretic Characteristics and Structural Seismic Performance of Magnetorheological Damping Self-Centering Braces

A dynamic performance test was conducted on a magnetorheological damping self-centering brace (MR-SCB) that can provide both Coulomb damping and viscous damping simultaneously. The results showed that the brace exhibited a full flag-shaped hysteretic curve, with excellent recentering and energy dissipation capabilities. Its energy dissipation in half-cycle did not change significantly with the change of the pre-pressed force and stiffness of disc spring group. The ultimate bearing capacity increased with the increase of the pre-pressed force and stiffness, while the residual displacement decreased with the increase of pre-pressed force. When the loading frequency and displacement were 0.7 Hz and 22 mm, respectively, the equivalent viscous damping ratio and residual displacement of brace were 0.215 and 5.3 mm, respectively, increasing by 14.4% and 61.1% compared with those under 0.3 Hz excitation. A nonlinear simulation analysis was conducted on a steel frame structure with MR-SCBs, and it was found that compared with traditional self-centering braces, MR-SCB dissipated more input seismic energy, achieving better control effect on the displacement of frame. Under rarely occurred earthquakes, the statistical dispersion of residual displacement response was lower, and the maximum result was reduced from 0.061% to 0.049%. The interstory drift and residual displacement of the structure decreased with the increase of proportion of viscous damping force of braces.