Studies on hollow Ball Joints for System Trusses

-Tensile Tests and Analyses on Screw Connection with Flat Nut Subjected to Out-of-plane Bending-

Abstract

In order to develop design of the hollow ball joint in roof trusses, tensile tests and Finite Element (FE) analysis were carried out on screw connection, which consist of a bolt and a flat nut subjected to outof- plane bending. Test results show that the ultimate capacity of connection is smaller than calculated value using shear strength of screw in the case of small bending stiffness of nut, which agree well with FE analysis. Based on results of a parametric FE analysis, an assessment of the ultimate tensile capacity of screw connections has shown in the form of a relationship between the ultimate capacity and bending stiffness of nut.