EXPERIMENTAL AND NUMBERICAL SIMULATION OF SMA-FRICTION DAMPER BASED ON GEAR MECHANISM

Based on the non-proportional stretching of shape memory alloy (SMA) wire by the gear mechanism, a novel SMA-friction damper is proposed and the basic configuration and working principle of the damper are expounded. The effects of loading amplitude and loading rate on the mechanical properties of SMA wires are investigated by cyclic tensile tests. The mechanical properties of the gear friction unit and SMA-friction damper specimens under cyclic loading are tested respectively to investigate the effects of friction materials, of preloading forces and of displacement amplitudes on the mechanical performance indexes, such as energy consumption per cycle, secant stiffness, equivalent damping ratio and self-centering rate. The simplified mechanical model of a SMA-friction damper is established and numerically simulated. The results show that the composite resin material has a greater friction and higher stability compared with brass material. The novel damper has excellent energy dissipation capacity, bearing capacity and self-centering capacity, and can be applied in a large displacement situation. The hysteresis curves computed using the OpenSees finite element model are in a good agreement with the experimental ones, which proves that the mechanical model and the secondary development of the material constitutive are valid.