A General Theory for Flexural-Torsional Buckling of Thin-Walled Members II: Fictitious Load Method

Abstract

There exist two different theories on the flexural-torsional instability of the thin-walled members, and based on them, very different results for beam elastic buckling can be obtained. In this paper, a new theory was presented to solve the inconsistency between the two different theories noted above after very deep investigation. In this new theory, the transverse stress was introduced as an important factor for member stability, in addition to the longitudinal and shear stresses and strains already considered in the work of others. A fictitious load method is used to derive the general theory in this paper. The fictitious loads are determined based on plate buckling theory, revised to take account of the overall flexural buckling of the members.