Torsion-extension coupling in initially twisted beams by finite elements

The analysis of initially twisted beams subjected to axial loads (extension and/or torsion) may be performed by finite element modelling of only a small slice of the beam cross-section. Accurate relationships between the related translational nodal degrees of freedom were formulated and used to maintain the helically symmetric deformation features. Consequently, conventional three-dimensional solid elements can be used for the structural discretization. Both linear and nonlinear examples are presented to show the validity of the method. Excellent agreement has been achieved compared with the previous analyses and experimental results.