14:30 Wednesday 3rd October 2018

Characterisation, Numerical Analysis and Design Improvement of Composite Cross-Country Ski Poles

An important aspect for improved competitiveness in cross-country skiing is weight reduction of poles. High-end carbon fibre reinforced polymer (CFRP) ski poles of today are lighter and stiffer than previous generations, explained by the times higher specific stiffness of CFRPs compared to aluminium. A negative aspect is however that ski poles have become increasingly brittle, which can have devastating consequences for the skier in a race. Thus, there is a strong need to find the best design of composite ski poles with a good balance between weight/inertia, stiffness and strength. To avoid resource expensive development on a “trial and error” basis, a better understanding of the mechanisms of failure in these poles under impact and transverse loadings is needed. There is also an apparent need to establish a predictive simulation driven design process in which different pole concepts can be tested and compared virtually. In the current work, we have investigated pole concepts by mechanical testing and by microscopy and fractographic investigations. The conclusion is that the strive for optimised weight and bending stiffness has driven the pole design to be sub-optimal with an increased sensitivity to transverse and impact loads. We have also developed numerical tools which accurately can predict the bending and stress state in ski poles under axial as well as transverse loading conditions. Thus, we here present a first step towards a simulation driven design process which when fully developed allows for finding an optimal balance between competing requirements on weight, stiffness and strength.

Martin Fagerström, Chalmers University of Technology