Formulation and evaluation of an analytical model for composite box-beams

A direct analytical beam formulation is developed for predicting the effective elastic stiffnesses and corresponding load deformation behavior of tailored composite box-beams. Deformation of the beam is described by extension, bending, torsion, transverse shearing, and torsion-related out-of-plane warping. Evaluation and validation of the analysis is conducted by correlation with both experimental results and detailed finite element solutions. The analysis is evaluated for thin-walled composite beams with no elastic coupling, designs with varying degrees of extension-torsion and bending-shear couplings, and designs with bending-torsion and extension-shear coupling. The analysis performed well over a wide range of test cases, generally predicting beam deformations within 10% of detailed finite element solutions. The importance of three non-classical structural phenomenon is systematically investigated for coupled composite beams.