Torsion of thin-walled composite beams with midplane symmetry

The optimization of thin-walled beams can lead to the design of structures whose walls have significant differences in stiffness. The stress field res ulting from a twisting moment is not correctly modeled by classical analyti cal theories, so numerical modeling is therefore essential. The analytical theory presented in this study provides its with a simple way of determinin g stress and stiffness in this type of structure, without having to resort to complex methods of calculation. The walls are made of isotropic or compo site materials with midplane symmetry and one orthotropic axis is the longi tudinal axis. The section may be open or closed and the constrained warping effect can be taken into account. The results obtained correlate accuratel y with those obtained from 3D FE modeling. (C) 2001 Elsevier Science Ltd. A ll rights reserved.