A General Theory for the Flexural-Torsional Buckling of Thin-Walled Members I: Energy Method

Abstract

There exists 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 is presented to solve the inconsistency between the two different theories noted above after very deep investigation. In this new theory, the transverse stress is 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. The energy method was used to derive the general theory in this paper. Based on the variational principles, the nonlinear potential energy of the external loads is excluded.