Experimental investigation on the seismic behavior of a novel self-centering friction damper

A new type of self-centering friction damper using Shape Memory Alloy (SMA) bars is developed. The proposed damper is composed of a friction energy dissipation system and a self-centering system. Its self-centering capacity and low repair cost after earthquake make it have great advantages when applied to earthquake resistant structures. The mechanical properties of SMA bars at different heating temperatures and the seismic performance the proposed damper were experimentally investigated. Results indicated that the damper exhibits a flag-shaped hysteretic behavior under cyclic loadings. As the friction force increases, the stiffness, bearing capacity, and residual deformation of the damper increase. As the loading rate increases, the energy dissipation and residual displacement of the damper decrease. A theoretical model is presented and compared with the test results. Nonlinear numerical models were developed in ANSYS software and parametric analysis were conducted. Results showed that as the diameter of the SMA bar increases, the bearing capacity and energy dissipation of the damper increase, and the residual displacement decreases. As the preload of the SMA bar increases, the residual displacement of the damper decreases, but the dissipated energy changes slightly.