Tubular Members. II: Local Buckling and Experimental Verification

Abstract

This paper summarizes results concerning the capacity of tubular members under combined loading due to external pressure and bending. A nonlinear finite-element technique, outlined in the companion paper is used. Three-dimensional analyses are performed towards an investigation of the effects of localized deformation. To verify the validity of the analytical procedure, computational results are obtained and compared with data from long-column and stub-column tests. Two-dimensional (cross-sectional) calculations furnish accurate estimates of the bending capacity of long, unstiffened tubes. However, three-dimensional effects must be taken into account when dealing with short tubes. Both experiments and computations show that short tubes undergo substantial inelastic deformation prior to buckling at a level of moment higher than the plastic moment. The presence of external pressure reduces the bending capacity and ductility of tubular members. Finally, in agreement with experimental data, the analytical results demonstrate the beneficial effects of capped-end compression on the pressure capacity of stub tubes.