Test of a novel self-centering brace using SMA slip friction damper

This paper reports an experimental work on a novel self-centering brace, which is a serial combination of shape memory alloy slip friction damper and steel tube. The study initiates with describing the axial behavior, in-plane rotational behavior and global buckling behavior of the brace, and deriving the corresponding analytical equations. Then, cyclic loading tests are conducted to obtain the hysteresis behavior of shape memory alloy bolt and the coefficient of kinetic friction of the sliding surfaces, both of which are critical to the behavior of the brace. In what followed, four tests are carried out on a 1/3-scaled specimen, corresponding to four loading protocols. The testing results indicate that the brace exhibits a flag-shaped hysteresis, which is characterized by excellent self-centering capability and satisfactory damping capacity. Using the experimental data, this work quantifies the peak strength, secant stiffness, energy dissipation and equivalent damping ratio, and analyzes the local strains and deformations. Furthermore, three-dimensional finite element models are established for nu-merical simulations. The finite element models capture the global and local behavior of the brace. Both the analytical equations and numerical simulations agree reasonably well with the experimental data.