Katarzyna Kowal-Michalska

Modal interactive buckling of thin-walled composite beam-columns regarding distortional deformations

Abstract The influence of modal interactive elastic buckling on the post-buckling behaviour of thin-walled composite beam-columns with imperfections is studied when the distortional deformations are taken into account. The investigation is concerned with open cross-section columns under an axial compression or/and a constant bending moment. The beam-columns are assumed to be simply supported at the ends. The asymptotic expansion established by Byskov and Hutchinson [Mode interaction in axially stiffened cylindrical shells, AIAAJ, 15(7) (1977) 941–948] is employed in the form of the numerical transition matrix method. The papers aim is to improve the study of the equilibrium path in the post-buckling behaviour of imperfect structures with regarding the second order non-linear approximation and the effect of cross-sectional distortions. The principal goal of numerical analysis is to investigate the influence of the wall orthotropy factor of columns upon the all buckling modes from global (flexural, flexural–torsional, lateral, distortional and their combinations) to local and upon the coupled post-buckling state. In the solution obtained the transformation of buckling modes with the increase of load up to the ultimate load and shear lag phenomenon is included.