Finite Element Simulation of Ice Pick Torquing (P97)

The ice axe is an essential tool for any mountaineer climbing in icy conditions. Ice axes are often used for climbing frozen waterfalls and icy rock faces. One of the techniques used in such climbs is known as torquing. This technique involves placing the pick of the ice axe into a crack and pulling on the ice axe handle to wedge the pick in the crack to give purchase for the climber. This technique was initially frowned upon by ice axe manufacturers as the pick was not designed for such loading, but it has become an accepted climbing technique and the manufacturers have modified their product accordingly. There have been a number of ice pick failures due to fatigue, where the crack was initiated at the root of the ice pick tooth. It has been suggested that torquing is responsible for these failures. In this study the ice axe pick was modelled using three dimensional elements. Two cases were analysed: the first a static finite element analysis assuming the tip of the pick is clamped and the second a transient analysis modelling the tip in a crack in the rock. The results showed that in the static case the highest stresses were not at the root of a tooth, but there were tensile stress concentrations in the root of the teeth nearest the handle. The transient analysis revealed a high shear stress at the root of the two teeth nearest the axe handle. In both cases these may result in the fatigue failure of an ice pick with the crack initiating at the root of a tooth.