Influence of Shear Deformation on the Local and Global Buckling Behaviour of Composite Thin-Walled Members

This paper presents the formulation of a shear deformable Generalised Beam Theory (GBT) developed to perform accurate analyses of the buckling behaviour of laminated plate composite thin-walled members displaying arbitrary orthotropy. Besides including the "conventional" (non-shear) deformation modes, this GBT formulation also incorporates a set of (new) shear deformation modes. Following the derivation of the equilibrium equations and corresponding boundary conditions, their terms are physically interpreted, i.e., related to the member mechanical properties. Then, the derived shear-deformable orthotropic GBT is used to investigate the influence of shear deformation on the local and global buckling behaviour of lipped channel columns displaying cross-ply orthotropy. The GBT results are validated through a comparison with numerical values yielded by thin-shell FEM analyses.