Interactive buckling of thin-walled beam-columns with intermediate stiffeners or/and variable thickness

Abstract

The design of thin-walled beam-columns must take into account the overall instability and the instability of component plates in the form of local buckling. This investigation is concerned with interactive buckling of thin-walled beam-columns with central intermediate stiffeners or/and variable thickness under axial compression and a constant bending moment. The columns are assumed to be simply supported at the ends. The asymptotic expansion established by Byskov and Hutchinson (1977: Byskov, E. and Hutchinson, J. W. (1977). Mode interaction in axially stiffened cylindrical shells. AIAA J., 15(7), 941–948) is employed in the numerical calculations performed using the transition matrix method. The present paper is a continuation of the papers by Kolakowski and Teter (1995a,b: Kolakowski, Z. and Teter, A. (1995a). Interactive buckling of thin-walled closed elastic column-beams with intermediate stiffeners. Int. J. Solids Structures, 32(11), 1501–1516; Kolakowski, Z. and Teter, A. (1995b). Influence of local post-buckling behaviour on bending of thin-walled elastic beams with central intermediate stiffeners. Engineering Transactions, 43(3), 383–396) and Teter and Kolakowski (1996: Teter, A. and Kolakowski, Z. (1996). Interactive buckling of thin-walled open elastic beam-columns with intermediate stiffeners. Int. J. Solids Structures, 33(3), 315–330) where the interactive buckling of thin-walled beam-columns with central intermediate stiffeners in the first order approximation was considered. The paper’s aim is to improve the study of the equilibrium path in the post-buckling behaviour of imperfect structures with regard to the second order non-linear approximation. In the solution obtained the transformation of buckling modes with an increase of the load up to the ultimate load, the effect of cross-sectional distortions and shear lag phenomenon is included. The calculations are carried out for a few beam-columns.