Walter PJ, Tushak CM, Hemler SL, Beschorner KE; Effect of tread design and hardness on interfacial fluid force and friction in artificially worn shoes; Footwear Science, vol. 13(3), pp. 245-254, 2021.

Abstract

Shoe wear is a major contributor to slip risk. Knowledge of the impact of shoe design features on wear progression and its impact on friction performance is emerging. This study investigated the effect of tread geometric design and shoe hardness on the shoe’s friction response to wear. Three tread designs (two designs using large tread lugs and one tread design using small-patterned tread features) each at three different hardness levels underwent available coefficient of friction (ACOF) and under-shoe fluid pressure testing on a vinyl composite tile contaminated with 90% glycerol solution. These tests occurred at baseline and after each of six iterations of an accelerated wear procedure. The results of this study revealed that tread design influenced under-shoe fluid force, friction, and their response to wear. One of the lug designs experienced high fluid pressures and low friction performance even in its new condition although its performance improved with wear. The other lug design exhibited good drainage, good friction performance, and resilience to wear. The small-patterned tread experienced high ACOF and low fluid pressures at baseline and declined in performance with wear. Thus, lug designs offer a wide range of friction performance and resilience. No effects were observed due to hardness. This study determined that tread geometry is an important factor for designing shoes with durable traction performance.