Non-linear pre-buckling behavior of shear deformable thin-walled composite beams with open cross-section

A kinematic model is presented for thin-walled composite beams able to account for axial force, bending, torsion and warping. Shear deformations on the mid-surface are considered and modeled by means of a polynomial approximation. For this scope appropriate shape functions on the curvilinear abscissa along the cross-section mid-line are introduced. Small strains and moderate rotations are considered over the pre-buckling range. The model allows to predict the static non-linear behavior and the critical loads of composite pultruded beams. A finite element approximation is derived from a variational approach. Some numerical results are also presented revealing the importance of the shear terms on the mechanical response and their effect on the stability of pultruded composite members. (c) 2012 Elsevier Ltd. All rights reserved.