Static analysis of thin-walled laminated composite closed-section beams with variable stiffness

Static behavior of thin-walled laminated composite closed cross-section beams having variable stiffness is investigated in this study. The analytical model used accounts for flexural-torsional coupling and warping effects as well as the variable stiffness along the contour of the cross-section of the beam. The variable stiffness is acquired by constructing the laminates with curvilinear fibres having certain specific paths. The orientation of fibres varies by depending on the fibre path along the contour of the cross-section in each layer. Equilibrium equations are derived by use of minimum potential energy principle. Although the formulation given can be applied to any shape of the closed cross-section with straight or curved edges, preliminary numerical results are presented only for box-beams. A displacement based finite element method is developed to solve the analytical model and to predict displacements and rotations under the effect of different types of loading conditions. Numerical results are obtained for different fibre paths and lay-up configurations and compared with the available solutions in the literature also with the results of a finite element analysis software using shell element. (C) 2017 Elsevier Ltd. All rights reserved.