U-Shaped Hysteresis SMA Damper for Seismic Isolation: A Numerical Study

Energy-dissipating damper is an effective way to reduce the response of civil engineering structures to earthquakes. Hysteretic dampers are extensively used as energy dissipation device to control the deformation in the structural system. In this direction, shape memory alloy (SMA) has unique re-centering capacity, which shows a flag-shaped hysteretic behavior and offers higher serviceability when used in the building. This research proposed a metallic yielding damper that utilizes this smart metal for creating the shape memory alloy U-shaped Damper (SMA-UD) with a trapezium cross-section. The trapezoidal-shaped U-damper (T-SMA-UD) was compared to the conventional rectangular cross-section under in-plane and out-of-plane cyclic loading. The yield strength, yield force (fy), yield displacement (δy), initial stiffness (K1), post-yield stiffness (K2), stiffness ratio (α), and energy dissipation capacity (Ed) of the suggested and traditional SMA-UD were studied and compared using numerical finite element (FE) analysis. The thickness, height, and width of the T-SMA-UD were adjusted as such that their cross-sectional area remains the same as that of standard rectangular-shaped U-plate damper. The suggested change in shape produced an optimum-shaped U-damper with considerably increased energy dissipation and deformation capabilities compared to that exists in the literature.