Static And Dynamic Performance Of Gear Semi-Rigid Joint Systems

The semi-rigid joints are usually assembled by a single or more bolts on site, and their actual behaviors do not conform to either rigid joint or pinned joint. The free-curved single-layer reticulated domes with semi-rigid joints have quite different mechanical behaviour from those assembled by rigid or pin joints. Semi-rigidly jointed spatial structures have merits such as reasonable stress distribution, construction convenience, material saving and high fabrication accuracy, etc.Nowadays, free-curved single-layer reticulated structures,which are free in form,more dynamic and have a beautiful mesh division,gradually become a hot spot in the field of architecture and trends. However, the bolt-ball joint’s stiffness is small,the application of which in the single layer lattice shell is clearly limited in China’s Technical specification for space frame structures, and other semi-rigid joints, such as End-face joint, which have enough stiffness, are not applicable for big change of curvature. In this study, a new semi-rigid joint system, gear joint, which is not only universal but also owns good bending stiffness and bending capacity, is proposed and tested for free-curved single-layer reticulated shell, and the main content of this paper includes:(1) Research and development of Gear JointBased on the features of free-curved single-layer reticulated structures,a new semi-rigid joint system, Gear Joint,which is not only universal but also owns good bending stiffness and bending capacity was developed, and this paper applied the method of theoretical and numerical simulation analysis for optimization of the Gear Joint.(2)Static performance of Gear Joint systemsThe influence of thickness of ball, diameter of gear bolt,tooth depth and number of teeth on the overall behavior of the gear joints was investigated by tests. The whole M-? curves and failure modes of the joints were obtained based on the different parameters.Three-dimensional FE models were established herein by means of the commercial FEA software ABAQUS to evaluate the bending stiffness, moment resistance, rotational capacity and failure mode of the joint under pure bending, tension-bending and compression-bending loads. The good agreement with the experimental results confirmed that the detailed FE models were able to simulate the mechanical behavior of gear joints with reasonable accuracy.(3) Dynamic performance of Gear Joint systemsBase on the study on the static performance of Gear Joint systems, a series of experiments, as well as numerical simulation, which investigate the influence of diameter of gear bolt, tooth depth and number of teeth,were conducted on the gear joints by quasi-static approaches. Hysteretic curves and skeleton curves of the Gear Joint were obtained to evaluate its seismic performance.(4)Theoretical analysis of Gear JointPower function and equivalent column method were adopted in the fitted curves of the stiffness and ultimate bending moment of the Gear Joint.The result was simulated for the experimental results in order to further demonstrate the effectiveness of mechanical property of Gear Joint, which are helpful for the engineering designers.