Study On Mechanical Behavior Of Hub Joints Of Space Grid Structures

The hub type node is an important node form in the reticulated shell structure,which has various forms and applications.In a reticulated shell structure with a small span or used with other forms of nodes,its role cannot be ignored.Common hub-type nodes generally weld the rod end inserts to the rods,and the difficulty of welding limits the further development and promotion of the hub-type nodes.Not only that,because the inclination angle of the connection between the rod and the joint is different,once the welding error is too large,the entire rod is scrapped,which has a particularly serious impact on the construction period.Therefore,this paper studies the way in which the rod end insert is directly flattened,which simplifies the process and improves the precision.In view of the problems existing in the hub-type nodes common in the existing specifications,I intend to study the rod-end inserts in the form of directly flattened hub-type nodes,and carry out the following research:(1)Referring to the calculation formulas in the existing grid structure specification and related node specifications,the center node size of an actual reticulated shell structure is calculated by hand,which lays a foundation and foundation for the following related calculations.(2)Perform axial compression analysis on the hub-type joint to determine its failure mode and mechanism.Consider changing the different parameters,such as the strength of the hub,the size of the rod and the angle of inclination,and analyze the similarities and differences of the damage.(3)Perform modal analysis on the rod and comb the reduction factor of the rod under axial compression so as to have a clearer understanding of its stiffness.(4)The bending analysis of the hub-type joints is carried out,and the different bending resistance properties in two planes are considered and compared,and the failure mode and mechanism are determined.(5)The force analysis of the hub-type joint under the combined bending and bending load is obtained,and the relationship between the ultimate bending moment and the ultimate axial force is obtained.