Modelling the cushioning properties of athletic tracks

In this work, a three-dimensional finite-element model of athletic tracks is presented. The model is based on data from quasi-static compression tests performed on small laboratory samples, to tune the constitutive parameters. The model was validated on three different athletic tracks, considering their top and bottom layers. Model predictions compared well with the results of shock absorption tests performed using a standard artificial athlete system, with relative errors of a few percent in terms of shock absorption. The model was then used to investigate the effect of the geometric structure of different tracks on their shock absorption capabilities. In particular, a reduction in size of the bottom layer cell pattern increased cushioning; the same property was shown to depend on the pattern voids depth in a non-monotonic way. A maximum in shock absorption was found for a void depth value about 40% higher than the one currently used in the analysed track patterns.