A shape memory alloy-based reusable hysteretic damper for seismic hazard mitigation

This paper presents a special shape memory alloy-based hysteretic damper with distinctive features such as tunable hysteretic behavior and ability to withstand several design level earthquakes. Superelastic nitinol stranded wires are used for energy dissipation in this damping device, termed a reusable hysteretic damper (RHD). By adjusting its design parameters, the hysteretic behavior of the RHD can be modified to best fit the needs for passive structural control applications. Adjustable design parameters of the RHD include the inclination angle of the nitinol wires, pretension level, and friction effect. A simulation-based parametric study was carried out to examine the effects of these design parameters of the RHD on its energy dissipating performance. The effectiveness of the RHD in passive seismic response control of civil engineering structures is examined through a nonlinear dynamic analysis of a three-story steel frame building with and without an RHD. The simulation results suggest that it can effectively reduce the structural response of building structures subjected to strong earthquakes. With proper design, an RHD can be reused for several strong earthquakes without the need for repair, due to the high fatigue life of nitinol wires.