Parametric Analysis On Compressive Load Capacity Of Stiffened Welded Hollow Spherical Joints

The development of large spatial reticulated structures is closely related to the development of nodes, currently applied in large-span structures of the node is the most mature welded hollow spherical joints, bolted joints and intersecting joints, etc. Welded hollow spherical joints in the application and research is more mature in our country, with the emergence of new structures as well as more complex structural system was born, the old form nodes has no longer applicable. So on the welded hollow spherical joints still have some problems to be further addressed currently.In actual projects on the diameter of more than 300 welded hollow balls need to set the stiffener, to prevent the destruction of its instability. The axial compression formula is obtained by regression analysis of experimental in our country present standard. The calculation of stiffened hollow spheres compression bearing capacity is based on the original formula multiplied by a 1.4-fold capacity increase factor, for each node in diameter are used to improve the bearing capacity of a single factor, not considered the impact of other parameters. For the engineering design some nodes design too conservative, some nodes design unsafe. And on the axial force, stiffeners affect on the bearing capacity of welded hollow ball has less researched.In this paper, theoretical analysis, finite element analysis, experimental verification three ways are used, systematic study on stiffeners welded hollow balls of different parameters in the case of the stiffeners on the load capacities of the sphere. Nodes of each ball diameter 500,450,400,350,300 case for example in this paper, build the finite element model, transform the different parameters, such as the sphere wall thickness, pipe diameter, pipe wall thickness and so on, implement the finite element analysis, by a variety of different parameters of the ball bearing capacity, compared with the standard formula, systematic study of the stiffener in the different parameters on the compression capacity of the sphere. Finally, through a number of groups with stiffeners welded hollow ball of full-scale model experiment, verify the accuracy of the finite element analysis.Through the finite element analysis and experimental validation methods, stiffener to axial pressure welding hollow ball joints under the influence of the carrying capacity was investigated, draw some conclusions. Welding hollow balls with stiffener failure mode is the strength of pipe, not the sphere buckling damage. Capacity improvement factor is not a fixed factor, but a variety of factors and variables. It is with pipe diameter and pipe wall thickness and other factors, with the increase of pipe diameter and pipe wall thickness increases, increase factor of the capacity is improved. The value of the specific needs a large number of experimental values through regression analysis to obtain, and the conclusions can be used for practical engineering or a related statute revision for reference.