Static Analysis of Frame by Localized Representation of Tubular Joint

In this paper, an experimentally-validated three-dimensional brick element model of a non-overlapped, tubular YT joint is employed to determine a local joint stiffness behaviour. The latter behaviour is then represented as an equivalent joint element with four nodes, two on the chord and one on each brace. Comparisons are made between the predicted framework behaviour using three different modelling approaches. The first employs beam elements away from the joints along with the new 4-noded joint elements, The second approach uses 3D brick elements throughout and the third employs beam elements throughout with rigid connections at the joint. The first and second approaches are shown to give very similar results, with the third (beam element) model predicting significantly lower deformation generally. A range of modelling issues important for accurate framework simulation of local joint behaviour via the local joint stiffness matrix approach are addressed, including the effects of mesh refinement and the necessary chord and brace lengths for the local joint model.