Cyclic Behaviour of a Novel Torsional Steel-Tube Damper

A novel metallic damper with torsional-yielding on the circular steel tube, called torsional steel-tube damper (TSTD), is proposed in this paper. Four specimens are designed for testing under cyclic loading to investigate their cyclic behaviour. The torsional-yielding mechanism contributes to the uniform yielding at the tube wall, results in an outstanding hysteretic performance and a high equivalent viscous damping ratio of about 0.5. Then the finite element analysis method is used for simulating the tested specimens, and the stress, strain, and parametric influence of the damper model are analyzed. Furthermore, a modified Bouc-Wen model is proposed to describe the cyclic behaviour of the tested specimens. The particle swarm optimization algorithm is used for identifying the model parameters. The identification results indicate that the modified Bouc-Wen model can accurately predict the hysteretic behaviour of the proposed damper. Finally, the proposed damper is implemented in a reinforced concrete frame model, and the nonlinear dynamic analysis method is adopted to assess the feasibility of the damper.