Experimental Mechanics

, 45:101

Experiments on snap buckling, hysteresis and loop formation in twisted rods


  • V. G. A. Goss
    • Centre for Nonlinear DynamicsUniversity College London
    • currently at London South Bank University
  • G. H. M. van der Heijden
    • Centre for Nonlinear DynamicsUniversity College London
  • J. M. T. Thompson
    • Centre for Nonlinear DynamicsUniversity College London
  • S. Neukirch
    • Centre for Nonlinear DynamicsUniversity College London

DOI: 10.1007/BF02428182

Cite this article as:
Goss, V.G.A., van der Heijden, G.H.M., Thompson, J.M.T. et al. Experimental Mechanics (2005) 45: 101. doi:10.1007/BF02428182


We give the results of large deflection experiments involving the bending and twisting of 1 mm diameter nickel-titanium alloy rods, up to 2 m in length. These results are compared to calculations based on the Cosserat theory of rods. We present details of this theory, formulated as a boundary value problem. The mathematical boundary conditions model the experimental setup. The rods are clamped in aligned chucks and the experiments are carried out under rigid loading conditions. An experiment proceeds by either twisting the ends of the rod by a certain amount and then adjusting the slack, or fixing the slack and varying the amount of twist. In this way, commonly encountered phenomena are investigated, such as snap buckling, the formation of loops, and buckling into and out of planar configurations. The effect of gravity is discussed.

Key Words

Twisted rodsrod experimentssnap bucklingloop formationsnarlinghocklingwelded boundary conditionsnitinolbifurcation

Copyright information

© Society for Experimental Mechanics 2005