FEM Analysis of Welded Spherical Joints' Stiffness

Welded spherical joints' stiffness has important influences on the strength and stability bearing capacity of reticulated shells. For complication of theoretical analysis and difficulty on experiments, the stiffness of welded spherical joints which is applied widely in the large-span reticulated shells, is analyzed and computed under the different conditions by finite element method with the structural analysis universal program SAP5 in this paper, the expressions of axial flexibility function f and flexural stiffness k(e) of welded spherical joints with parameters: joints' diameter and thickness, members' diameter are attained by regression analysis for lots of computing results. Here, orthogonal design and orthogonal multi-item formula are accepted. These expressions can be adopted by the non-linear stability analysis of the large-span space reticulated shells with the welded spherical joints considering the influence of joints' stiffness.