The in-plane behaviour and FE modeling of a T-joint connection of thin-walled square tubes

The behaviour of square hollow tubes with T-joints subjected to in-plane loading conditions is examined numerically. The stresses in the joint and its stiffness are determined from the finite element (FE) models using 2-D shell and 3-D solid elements. The parameters identifying the joint's stress concentration (ξm, ξb), and the bending stiffness reduction (αK) are defined in terms of the ‘thin-wallness’ ratio (the side length to thickness) of the tube. These parameters permit modeling accurately the tubes and the T-connection by simple 1-D beam elements with certain properties modified. The FE models consisting of beam elements are significantly easier to prepare and analyze. The effectiveness of the approach is demonstrated by applying it to a structure with a T-connection and dimensions typical for the agricultural industry. It is shown that such beam models provide accurately all important information of the structural analysis (i.e., the stresses, displacements, reactions forces, and also the natural frequencies) at substantially reduced computational effort in comparison with the complicated FE models built of shell or solid elements.