Research And Development Of Bolted Hollow Spherical Shell Joints

Spatial grid structures are a commonly used structural form in large-span buildings.The connection structure and performance of its joints are directly related to structural safety,construction period,and economic benefits.Bolted ball joints have the advantages of high degree of assembly and high construction speed.Welded hollow spherical joints have the characteristics of convenient rod alignment,high stiffness,and good airtightness.The technological advancement,safety applicability,and economic rationality of the spatial grid structure will be greatly improved if we can get a joint that combines the advantages of the two common joints mentioned above.Based on research by the research group,this paper researches space structure joints using pipe-like components.The main work content and results are as follows:(1)The structure and characteristics of drum-shaped spherical shell joint and bolt spherical shell joint are summarized,and the structural design is carried out to obtain the bolted hollow spherical shell joints without mounting holes,with good durability,and subsequent installation datum planes,which are suitable for multi-layer grid or tube truss.(2)The whole model of the spherical shell,high-strength bolt,curved European nut,single-curved washer,and sleeve are established.Using ABAQUS finite element analysis software to analyze the force performance under axial force,and obtain the stress distribution and variation law of each component,failure mechanism,etc.(3)The influence of main parameters such as D,T,D/T,bolt specification,circumscribed circle diameter e of sleeve cross-section,and nut diameter d_m are analyzed in contact with ball shell end on the bearing capacity of the hollow bolt spherical shell joint.The calculation formula for the bearing capacity of the joint is proposed.(4)The influence of the thickness,width,length,arrangement,and quantity of stiffeners are discussed in the hollow sphere on the bearing capacity of the bolt hollow spherical shell joint.(5)Aiming at the newly-built grid structure of a university laboratory,we designed welded hollow spherical joints,bolted spherical joints,and bolted hollow spherical shell joints,and compared characteristics include structural steel consumption,connection structure,assembly degree,field welding workload,and centralization,etc.The results show that the comprehensive benefits of using bolted hollow spherical shell joints are significant.