7. Summary and conclusions
The research investigated the cyclic behavior of a self-centering hybrid damper which is comprised of energy dissipating and recentering components. Hysteretic behavior of SMA which resulted from numerical modeling was in good agreement with experimental results. Furthermore, parametric study was performed to evaluate the effect of design parameters on the SCHD characteristics. Results indicated that increase in wire slope unfavorably affects the flag-shaped hysteresis loop of SCHD. It should be pointed out that a methodology for optimal design of SCHDs could be one of critical improvements in this type of structural control. An optimization process was performed to obtain an incorporation percentage of SMA at which both promising properties of SCHD have ideal values. Then, the effect of cycle numbers on hysteresis loops of SCHD was investigated. The results indicated that loading under several cycles is reliable due to better representation of buckling. Embedment of hybrid damper between the beam and bracing system will concentrate the fundamental damages within these special devices. So, the main structural system is intended to have little or no damage. The outcomes of nonlinear time history analysis showed that the hybrid damper can reduce the permanent displacement, peak interstory drifts and acceleration of the seismically excited structure. Results of the investigation emphasized that performance of the steel component as an axial member could better improve the recentering property of the SCHD. Thus, further researches are essential to investigate the behavior of SCHDs with both components under axial loading. In addition, it seems necessary to confirm the numerical results experimentally.
