Simplified Analysis of Thin-Walled Composite Members

In thin-walled open sections made of composite material, symmetric with respect to their midplane, the bending and torsion are coupled. In this paper, new equivalent moduli of elasticity and rigidity are introduced for this type of material to allow decoupling of the relative differential equations. Therefore, for analysis of composite thin-walled members, the Vlasov relations with the new equivalent moduli could be used. In other words, the material could be treated as an isotropic and homogeneous one. As a result, the required computation efforts and time could be minimized. The results of two examples, presented in this paper, are in good agreement with the finite-element solution developed in the companion paper.