A coupling cross-section finite element model for torsion analysis of prismatic bars

A general finite element model has been developed for the analysis of prismatic bars subject to torsional loading by modelling only a small slice of the bar. Exact analytical coupling deformation relationships between the artificial cross-sections, which are independent of the position of axis of rotation, have been formulated. Three examples from the range of analyses that have been evaluated have been selected to demonstrate the accuracy and effectiveness of the method. Analyses for an orthotropic elastic square cross-section bar, an elastic–plastic circular cross-section shaft containing a radial crack, and geometrically nonlinear deformation of a thin-walled I-section beam are presented and compared with previous results, where available.