Experimental Study of a Self-Centering Damper with Multistage Energy-Dissipation Mechanism

This paper reports an experimental and analytical investigation on a novel self-centering damper. The damper is characterized by a multistage energy-dissipation mechanism, which is desirable for multiperformance-based seismic designs. The conceptual design, working mechanism, assembling process and hysteretic performance of the proposed damper are presented. The fundamental mechanical behavior of each component of the damper was examined experimentally. Then a series of cyclic tests of damper specimens was conducted, focusing on the influence of the preload of the shape-memory alloy (SMA) bolts, the SMA bolt type, and the sloping angle of the wedge-shaped friction plates on the damper performance. An analytical model is proposed for quantification of the hysteretic behavior of the damper. The test results showed that the damper specimens exhibited the expected multistage energy-dissipation characteristics and stable flag-shaped hysteretic curves with full self-centering behavior. A good energy dissipation capacity with an equivalent viscous damping (EVD) of about 20% was observed, which basically was consistent over the entire loading stages. The overall behavior of the damper was related closely to the aforementioned test parameters, indicating that the damper performance can be adjusted flexibly according to various seismic design requirements. The analytical predictions and the test results of the damper were in good agreement, indicating that the developed analytical model can be used confidently by engineers for the design of the developed damper.