Parametric Study of Simulated Tennis Shoe Treads

We report on friction properties between simulated tennis shoe treads created in house and a hard court tennis surface approved by the International Tennis Federation. To simulate tennis shoe tread, we use the compound N70 Nitrile Butadiene Rubber, which possesses similar physical characteristics as commercial tennis shoe treads, namely hardness, tensile strength, and elongation percentage. Into that compound we have created a series of tread patterns with various shapes, spacing, and heights. An in-house traction rig allows for the maintaining of a constant vertical load while a horizontal load is monotonically increased until our tread slips on the hard court tennis surface. Our experimental apparatus allows us to test a range of rubber compound areas and tread patterns. We performed experiments with different vertical loads and extracted both static and dynamic friction coefficients using force data supplied by load cells mounted vertically and horizontally. Variations in the compound's tread geometry lead to different friction coefficients. We also rotated our tread patterns over a range of angles and extracted associated friction coefficients. Our results have moved us closer to a better understanding of optimal tread patterns on a tennis shoe. Such results are especially of interest to us as sliding is becoming a more prominent feature of elite tennis play on hard courts.