Helical buckling of thin rods: FE modelling

In this paper, we utilize the Finite Element (FE) method to model twisting of long thin rods and capture the bifurcation scenarios leading to heli- cal buckling and various further post-buckling states. Since standard nonlinear beam elements do not account for nonlinearity in torsional mode, we derive a modified beam element, which allows to model complex torsional buckling bifurcation scenarios of a thin rod subjected to twisting load. A series of veri- fication tests (static analysis with load stepping) of the developed code are per- formed to determine critical torsional buckling loads for various helical buck- ling modes and compared with ABAQUS FE simulation