Experimental and numerical studies on hysteresis performance of U-shaped SMA-steel plates damper

This study developed a novel prefabricated self-centering U-shaped SMA-Steel hybrid plate damper (SMA-SteelUD) based on the excellent characteristics of SMA, to reduce the residual deformation of the conventional Ushaped Steel plate damper under severe earthquakes. The developed SMA-Steel-UD consisted of U-shaped SMA plates (SMA-Us) and U-shaped steel plates (Steel-Us) assembled in parallel, and its working principle was introduced and the analytical model was established. Then, the mechanical properties of SMA plate were firstly investigated experimentally, and the test results showed that the SMA plate behaved large self-centering capacity and great deformability. Subsequently, the quasi-static cyclic loading tests of the components of the damper including U-shaped SMA plate damper (SMA-UD) and U-shaped Steel plate damper (Steel-UD) and the whole damper were carried out to investigate the hysteretic performance, and to further validate the established analytical model. The experimental results showed that the SMA-Steel-UD exhibited satisfactory flag-shape hysteresis behavior with excellent self-centering ability and stable energy dissipation capacity, and owned a large deformation capacity. Parametric studies were further performed to evaluate the influences of the key parameters of SMA-Steel-UD on the hysteretic performance. To ensure the excellent self-centering capacity of the damper, the total self-centering force of the U-shaped SMA plates should be greater than the total yield force of the U-shaped steel plates.