Torsional modeling of thin-walled beams with open and closed cross-sections

摘要

Many structures include thin-walled beam elements with different types of cross-sections or with large openings. In these elements, torsional loads induce a significant warping which is restrained by the stiffness of supports and connections (pure pin, fully fixed or semi rigid). In this paper, a beam theory is presented that allows complete compatibility for the warping deformation of two adjacent elements with different cross-sections. The effects of non-uniform torsion are taken into consideration in the computation of stresses, deformations and displacements. Deriving from Prokic's work (Prokic 1993), a unique warping function is used for arbitrary open or closed thin-walled cross-sections. It easily enables the assembly of different cross-sections and offers a multiple choice for the description of a joint. An elastic analysis, starting from the principle of virtual displacements, uses the finite element method to study the behavior and stability of a three-dimensional structure assembled by arbitrary thin-walled prismatic beams.