Stiffness Analysis for Hollow Spherical Joints

Hollow spherical joints' stiffness has important effect on the strength and stability bearing capacity of reticulated shells. Because of complication of theoretical analysis and difficulty on experiments, the stiffness of hollow spherical joints which are applied widely in the large-span reticulated shells, is analyzed and computed under the different conditions by finite element method with the program SAP5 in this paper, the expressions of axial flexibility function f and flexural stiffness k(e) of hollow 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 reticulated shells with hollow spherical joints considering the effect of joints' stiffness.