Finite element analysis and hysteretic model of self-centering steel connection with dual energy dissipation mechanism

In the traditional steel beam-column connection, the beam flanges were welded to the column face, while the beam web was bolted to the column face by shear tab. During seismic events, this connection often suffers from brittle failure. This paper presents a novel self-centering steel connection with dual energy dissipation mechanism. The connection utilizes the sliding of friction elements and the plastic deformation of T-stub at different stages to dissipate energy. As a result, the proposed connection not only enhances energy dissipation capacity but also increases the safety redundancy of the structure. The main focus of this study is to investigate the structural behavior of this new type of connection by refined finite element analysis models. These models are constructed using ANSYS and validated against experimental results. Furthermore, parametric analysis is conducted to investigate the influence of various factors on the seismic performance of the connection. These factors include the initial post-tensioning force of prestressed steel strands, the shape form of T-stub flange, the flange thickness of T-stub, the coefficient of friction between friction plates and web of T-stub, and the pre-tension force of highstrength bolts. The results demonstrate that increasing the initial post-tensioning force of the steel strands reduces the residual deformation and enhances the self-centering ability of the connection, and the dual energy dissipation behavior is more obvious. Meanwhile, the occurrence of both sliding and plastic deformation of Tstub is postponed. The influence of the thickness of the T-stub flange is minimal during the friction-based energy dissipation stage but significant during the energy dissipation stage of the plastic deformation of T-stub. Moreover, increasing either the coefficient of friction between friction plates and T-stub webs or the initial posttensioning force of high-strength bolts significantly improves the bending strength of the connection and reduces residual deformation. Meanwhile, these factors mostly affect the friction sliding stage to delay the starting point of sliding, but their influence on the plastic deformation is minimal. Finally, a theoretical hysteretic model is proposed based on the dual energy dissipation mechanism. The model is compared and analyzed against experimental results, demonstrating good agreement. This provides theoretical foundation for the design of similar structural connection.