Numerical analyses of semi-rigid joints subjected to bending with and without axial force

Socket joint systems are typical semi-rigid joints used in space structures. This paper presents numerical analyses of semi-rigid joint systems in which the bolts are pretensioned. Eleven numerical models of socket joints are studied: three of them are subjected to bending and the others are subjected to proportional bending and axial compression. Moment-rotation relationships of the joints are obtained using models in which the material and geometric nonlinearity are taken into account. The load-carrying mechanism of socket joint system is investigated in detail through the numerical analysis. Through comparison of the finite element analysis (FEA) and corresponding test measurements, it is shown that the proposed FEA models can be used effectively to describe the mechanical performance of the semi-rigid joints in spatial structures, including the initial bending stiffness, ultimate bending moment, deformation and the failure mode.