Elasto-plastic finite element analysis of double chord rectangular hollow section T-joints

Elasto-plastic response of T-joints consisting of double chord, rectangular hollow sections (RHS) has been modelled by treating the chord's mated flanges as thin plates supported by coupled springs that simulate the action of the side walls and bottom flanges. Two loading conditions, namely, branch axial force and branch bending are analyzed. The finite element formulation includes rectangular plate and edge boundary springs in which both in-plane and out-of-plane actions are considered. This paper is an extension of a previous study of the joints' elastic behaviour. Material nonlinearities are incorporated through the Von-Mises yield criterion and its associated flow rule and the Newton-Raphson method is used for the nonlinear analysis. The model is used to determine the ultimate strength and the load-deformation curves for both double and single chord T-joints. The numerical results obtained are in good agreement with some experimental results available in the literature.