Elastic-Plastic Buckling of a Finite Length Cruciform Column

Elastic-plastic buckling of a finite length cruciform column is studied by numerical methods. Previous analytical and numerical studies of an infinitely long cruciform column have shown the paradoxical result that buckling calculations based on any incremental plasticity theory with a smooth yield surface are uninfluenced by plasticity, whereas computations based on deformation theory depend on the level of plasticity.

The numerical results in this study show that for finite length columns, incremental theory predictions will be influenced by plasticity, but not as much as predictions of deformation theory. In a study of Gjelsvik and Lin, the effect of the finite length was found to arise from frictional stresses on the loaded side, but our numerical results indicate that this effect is negligible.