A Kollár and Pluzsik Anisotropic Composite Beam Theory for Arbitrary Multicelled Cross Sections

In this paper we extend Kollár and Pluzsik’s thin-walled anisotropic composite beam theory to include multiple cells with open branches and booms, and present a finite element formulation utilizing the stiffness matrix obtained from this theory. To recover the 4x4 compliance matrix of a beam containing N closed cells we solve an asymmetric system of 2N+4 linear equations 4 times with unitary section loads and extract influence coefficients from the calculated strains. Finally, we compare 4x4 stiffness matrices of a multi-celled beam using this method against matrices obtained using the finite element method to demonstrate accuracy. Similarly to its originating theory, the effects of shear deformation and restrained warping are assumed negligible.