The Occurrence Limit of Strain Nonuniformity in Thin-Walled Cylinders Subjected to Cyclic Torsion

The symmetry limit theory for 3-D continua developed by the authors, is applied to predictions of the occurrence limit of nonuniform strain in cylinders subjected to cyclic torsion. Bifurcation analysis of a steady-state path, which was defined as a continuous sequence of steady states generated under continuous increasing amplitude cyclic loading, is performed for the cylinder model. The deformation mode with very short wavelength in the circumferential direction is obtained, analogous to that in the internal buckling of a rigidly confined continuum shown by Biot. It is shown that this circumferential short-wave mode occurs at much smaller amplitude than the bifurcation under monotonic torsion.