Papers Published

1. Wilson, J.F., Energy threshholds for tumbling springs, Int. J. Non-Linear Mech. (UK), vol. 36 no. 8 (2001), pp. 1179 - 96 [S0020-7462(00)00088-3] .
   (last updated on 2007/04/09)

   Abstract:
   A gravity-driven, weak helical spring such as the toy Slinky may be activated to tumble end-over-end. One way to activate this spring motion is to bend the coil assembly in a 180° are, set each end on a horizontal support surface, and suddenly pull away one end support so that the spring impacts a step below. The nature of subsequent tumbling depends on critical step heights, the lower bounds of which are predicted for 180° and 360° somersaults. Such predictions, presented in terms of non-dimensional system parameters, are based on structural analysis and energy threshholds: an ideal balance of gravity potential energy and elastic spring energy. The predictions are complemented with experimental results, which include the effects of the compliance of the impacted surface and spring payload. Results may be applicable to the future design of unique tumbling spring “wheels” for all-terrain mobile robots

   Keywords:
   bending;classical mechanics;elastic constants;impact (mechanical);