INFLUENCE OF MODIFICATION OF BOUNDARY-CONDITIONS ON LOAD-CARRYING CAPACITY IN THIN-WALLED COLUMNS IN THE 2ND-ORDER APPROXIMATION

The influence of modification of boundary conditions at both ends of t he structures regarding interactive buckling on the postbuckling behav iour of thin-walled elastic columns with imperfections is studied. The investigation concerns thin-walled closed and open cross-section colu mns under axial compression. The columns are assumed to be simply supp orted at the ends. The asymptotic expansion established by Byskov and Hutchinson is employed in the numerical calculations in the form of th e transition matrix method. The aim of the paper is to improve the stu dy of the equilibrium path in the postbuckling behaviour of imperfect structures regarding the second order approximation.