On torsion of closed thin-Wall members with arbitrary stress-Strain laws: A generalcriterion for cross sectionsexhibiting no warping

Warping due to torsion of closed thin-wall elastic members having constant thickness isinvestigated under the assumption qf small strain but with arbitrary isotropic shearstress-strain laws. Based on a derived general criterion, it is shown that there exists aclass qf cross-sections which undergo no warping. For cases where warping exists, an example of simplified calculations, using the derived expressions, is presented for warp-ing of a thin-wall rectangle.