Elastic buckling of elliptical tubes subjected to generalised linearly varying stress distributions

The structural behaviour of elliptical hollow sections has been examined in previous studies under several loading conditions, including pure compression, pure bending and combined uniaxial bending and compression. This paper examines the elastic buckling response of elliptical hollow sections under any linearly varying in-plane loading conditions, including the most general case of combined compression and biaxial bending. An analytical method to predict the elastic buckling stress has been derived and validated against finite element results. The predictive model first identifies the location of the initiation of local buckling based on the applied stress distribution and the section geometry. The critical radius of curvature corresponding to this point is then introduced into the classical formula for predicting the elastic local buckling stress of a circular shell. The obtained analytical results are compared with results generated by means of finite element analysis. The comparisons between the analytical and numerical predictions of elastic buckling stress reveal disparities of less than 2.5% for thin shells and, following an approximate allowance for the influence of shear, less than 7.5% for thick shells.

► Literature review of elastic buckling in elliptical hollow sections (EHS).
► Derivation of analytical solution for elastic buckling of EHS under generalised linearly varying stress distributions.
► Validation of analytical model against numerical results for thin shells.
► Modification of analytical results for thick shells.
► Validation of analytical model against numerical results for thick shells.