Initial Postcritical Behavior of Thin‐Walled Angle Section Columns

This work deals with the overall flexural instability of an angle section column under axial load, taking into account deformations of the cross section as buckling occurs. A nonlinear differential formulation with two variables is considered. The perturbation method is used to follow the initial postbuckling behavior from the bifurcation point. Deformations of the cross section do not modify the Euler critical load, but they may significantly affect the nature of the postcritical path. Unlike the well-known behavior of columns with solid cross sections, the angle section may exhibit unstable postbuckling deformations typical of the light-gauge sections, as reported in previous studies on thin circular arc sections.