LOCAL POST-BUCKLING BEHAVIOUR OF ELLIPTICAL TUBES

The local post-buckling behaviour of elliptical hollow section (EHS) tubes under compression is analysed in this paper. It is found that EHS tubes with low to moderate aspect ratios can support loads up to their limit loads but are imperfection sensitive (shell-type behaviour), while EHS tubes with moderate to high aspect ratios can carry loads higher than their limits loads (plate-type behaviour) and are imperfection insensitive. For increasing EHS aspect ratio, it is found that the compressive stresses accumulate near the zones of minimum radius of curvature while the zones of maximum radius of curvature experience a relatively low compressive stress level. Thus, it is likely to apply the effective width concept to EHS tubes with moderate to high aspect ratio.