Importance of Section Properties on Modelling of Thin-Walled Beam with Restrained Torsion

The behavior of thin-walled sections has been affected by restrained warping as it plays a vital role in the torsion deformation and axial stresses of thin-wall open sections. Major errors in torsional response can result if the warping effects are ignored. Warping-based stresses and deformations in closed sections are assumed to be insignificant and have been neglected. The classical beam models are generally restricted to the modelling of uniform torsional behavior and the Saint-Venant concepts and different non uniform torsion of thin-walled section which considers for the warping and shear deformation due to restrained torsion are developed. The finite element calculation for restrained torsion of thin-walled beams of open and closed sections depends on the geometrical properties of the section. In this study, the main factor to identify the behavior of open and closed thin-walled sections is the value of characteristic numbers for torsion. As its value depends on the geometrical properties of the section, it indicates that the torsional behavior of the section can also be described similarly by geometrical properties. The trigonometric and approximation solutions of an interpolation function are considered to express the stiffness matrix for the non-uniform torsion by considering an additional degree of freedom at each node. The two numerical methods are compared graphically to the warping behavior of the restrained torsion. © 2023 American Institute of Physics Inc.. All rights reserved.