Collapse of composite tubes under end moments

The Reissner (1959) approximate closed-form solution of the collapse of isotropic tubes subject to end moments is presently extended to encompass specially orthotropic material. This closed-form solution is verified via extensive nonlinear FEM analysis of the collapse of long tubes under applied end-moments; the radius/thickness value and composite layup ranges are representative of space-station truss framework designs. The FEM analysis validates the assumption of an inextensional deformation of the cylindrical cross-section, as well as the approximation of the material as specially orthotropic.