Cyclic behavior of SMA slip friction damper

Abstract

This paper proposes a new type of self-centering (SC) damper which exploits the shape memory alloy (SMA) bolts and variable friction mechanism, termed the SMA slip friction damper (SMASFD). The theoretical equations governing the force–displacement relationship, the equivalent stiffness and the equivalent viscous damping are first derived. Then, the application potential of such damper is briefly discussed. In the experimental study, the results of the experimental validations of the SMA bolts and the friction mechanism are presented, followed by the results of proof-of-concept test on the fabricated SMASFDs. According to the testing results, the damper exhibited a symmetric tension–compression flag-shaped hysteresis characterized by excellent SC capacity and good damping capability. The prestrain treatment was applied to the SMA bolts in one test, which was found effectively increased the initial stiffness of the damper. To provide a further understanding on the damper and examine the stress and strain demands of the components, high-fidelity finite element models were established for numerical simulations. Both the analytical method and numerical simulation were validated by the experimental data.