Experimental and Simulation Study on the Hysteretic Behavior of Double-Ring Joints for a Single-Layer Grid Shell under Cyclic Eccentric Loading

Based on the mechanical characteristics of assembled joints in a single-layer grid shell, a cyclic eccentric loading method was designed to study the hysteretic behavior of double-ring joints under the action of axial force and moment through experiment and finite element analysis. The effects of structural parameters and axial force eccentric distance on the failure mode, hysteretic behavior and energy-dissipating capacity of double-ring joints were explored, which laid a foundation for the research on dynamic collapse properties and shape optimization of grid shell. The following conclusions were obtained: 1) Two main failure modes occurred for double-ring joints: the fracture of the bolt and the fracture of the central ring at the bolt hole. The failure mode was affected by the axial force. 2) All the hysteretic loops included five stages, and the plastic deformation of the central ring improved the energy-dissipating capacity of the joint. 3) Under the action of eccentric compression with eccentric distance δ ≤ 80 mm and eccentric tension, with increasing eccentric distance, the rotational stiffness and ultimate bending moment increases. Under the action of eccentric compression with eccentric distance δ \u3e 80 mm, the eccentric distance has little effect on the rotational stiffness and ultimate bending moment