Research On Bearing Capacity Of Welded Hollow Spherical Joints Of Steel Tube Conical Head

In space grid structure,welded hollow spherical joints are widely used for its simple structure,convenient connection and unlimited specifications.In recent years,the space grid structure has been developing in the direction of more and more span and more complex structure,which makes the diameter of the welded hollow ball on the node of the grid structure bigger and bigger.This not only affects the overall beauty of the structure,but more importantly,with the increase of the hollow ball,the processing and field construction of the factory is more difficult,and the production quality of the ball can not be effectively guaranteed.On the basis of previous research,this paper optimizes the steel pipe diameter and welded hollow ball joints proposed by the predecessors,and analyzes the model by using the ABAQUS finite element analysis software.In this paper,the pipe necking and welded hollow ball joints are called pipe cone joint hollow ball joints.This is a new type of grid structure node,which is the advantages of two kinds of joint,which are welded hollow ball joints and bolt nodal joints.In order to make the new welded steel hollow conical joint welded hollow sphere node better,it can achieve industrial production and is more convenient to be promoted in grid structure engineering projects.This paper will design the structure of the conical head of steel pipe,and induce the geometric parameter information of commonly used steel tube cone in engineering.Several nodes are drawn from it to model and analyze it with ABAQUS finite element software.According to the simulation results,the stress development,bearing capacity and failure mechanism of the welded hollow ball joints are compared and analyzed.The influence of different materials on the diameter reduction of the steel tube cone is analyzed from the aspects of reducing diameter and steel volume.In this paper,through the finite element analysis of 389 groups of pipe cone welded hollow ball joints under the action of unidirectional pressure,the influence of the outer diameter of the cone head and the ratio of the outer diameter of the ball,the thickness ratio of the hollow sphere and the outer diameter of the hollow sphere on the bearing capacity of the joints is investigated.Based on these simulation results,the bearing capacity calculation formula of the new welded hollow spherical joints is fitted by numerical method.Then,the calculated formula of bearing capacity is compared with the formula of bearing capacity given in the current grid code.In the end,in order to verify the practicability of the new pipe conical head welded hollow ball joint,this paper selects the intersecting node in the actual project(a network frame structure in Shouyang),and reduces the diameter of the selected intersecting nodes according to the geometric parameters of the common steel pipe shrinkage given in the article.The finite element analysis of the joints before and after shrinkage is carried out by ABAQUS,and the bearing capacity and deformation of each node under the same load condition are analyzed.The research results show that if the node can be widely used in the grid structure,it can not only effectively reduce the proportion of steel nodes in the network frame structure,but also reduce the difficulty of processing and construction,beautify the appearance of the structure,improve the bearing capacity of the nodes,and even control the specifications of the hollow center ball of the same project.