Lateral buckling of box beam elements under combined axial and bending loads: Fid-Bau Portal

Lateral buckling of box beam elements under combined axial and bending loads

Saoula, Abdelkader / Meftah, Sid Ahmed / Mohri, Foudil / Daya, El Mostafa

Abstract The effect of distortional deformation on the elastic lateral buckling of thin-walled box beam elements under combined bending and axial forces is investigated in this paper. For the purpose, an analytical model is developed for the stability of laterally unrestrained box beams according to higher order theory. Ritz and Galerkin's methods are applied in order to discretize the governing equilibrium equations and then the buckling loads are obtained by requiring the singularity of the tangential stiffness matrix. The different solutions are discussed and then compared to the finite element simulation using Abaqus software where shell elements are used in the mesh process. The numerical results reveal that classical stability solutions as those adopted in Eurocode 3 overestimate the real lateral buckling resistance of thin-walled box beam members, particularly for the ones with high ratios between the height and the thickness of the cross-section. Numerical study of incidence of compressive forces on lateral buckling resistance of thin-walled box beam is investigated.

Highlights • New nonlinear kinematic model including the distortional deformation component • Nonlinear lateral buckling problem by Galerkin and Ritz methods is developed. • New analytical solution for calculation of the critical moment is proposed. • The results given by the proposed method agree very well with those of the FEM.