Instability of Thin Walled Bars

Energy equations governing the flexural, torsional, and lateral instability of thin walled bars of open cross section are derived. Shear deformations due to nonuniform bending, and distortion of the cross section are not considered, but the influence of pre‐buckling displacements is included in the analysis. Solutions of the governing energy equations are obtained, by the finite element method, which agree with closed form solutions based on the governing differential equations.