An Experimental Study of an SMA-Based Self-Centering Damper

The self-centering energy dissipation devices can reduce or avoid the residual inter-storey drifts of structures. This study aims a shape memory alloy (SMA) -based self-centering damper that employs the pre-tensioned SMA wires and pre-compressed springs as energy dissipating group and re-centering group, respectively. Compared with the conventional self-centering dampers which mainly use SMA wires to offer restoring forces, this damper possesses much reliable re-centering capability. The configurations, detailed assembly process and working principle of the damper are introduced. In order to evaluate the hysteretic behaviour of the damper, a damper specimen was manufactured and a series of quasi-static mechanical tests were conducted on the specimen with considering the influence of load amplitude and loading frequency. The results indicate that the dissipated energy per cycle greatly increases while the equivalent viscous damping ratio shows a slight change with the increase of load amplitude. Loading frequency has a great influence on the equivalent viscous damping ratio of the damper. To improve the energy dissipating capacity of the damper with maintaining its full re-centering capability, it is suggested that the pre-compression force applied to springs should be equal to the force difference between the two groups SMA wires at the equilibrium position.