Computational techniques for the elastic—plastic analysis of tubular joints

The applicability of a non‐linear finite element method for the determination of the static strength of tubular joints is examined. In order to establish static strength, non‐linear elasto‐plastic models are implemented. Techniques for automatically generating finite element meshes in stress analysis of tubular intersections are used. The analysis is carried out on a typical X‐joint under axial brace loads and the model represents only one‐eighth of the joint. The results are obtained by two different element procedures: three node flat shell element (Ilyushin yield criterion); eight node isoparametric shell element (von Mises yield criterion). The objective of this work is to discuss the modelling and computational aspects which are required for dealing with this elasto‐plastic analysis and to determine the necessary degree of refinement in order to obtain reliably the loads at which ultimate failure occurs.