Development of a new analyzing model for quantifying pedestrian slip resistance characteristics: Part I - Basic concepts and theories

摘要

This paper suggests new theoretical foundations for characterizing friction and wear phenomena observed at the sliding interfaces between the footwear and underfoot surfaces. Among many factors, geometrical arguments (surface roughness and asperity interlocking) are mainly explored to identify tribological features of the shoes and floors and analyze their effects on slip resistance properties. Because surface topography of the shoes and floors could be largely changed throughout the course of sliding friction, this may affect the overall friction behavior and be one of the most important factors to influence the slip resistance properties. As a result, both the surfaces that may have initially statistically uniform topography could exhibit non-uniform surfaces. Based on these hypotheses, a new tribology model is proposed to characterize friction and wear behaviors and quantitatively measure the geometrical interactions between the shoes and floors during the slip resistance assessments. To quantify the geometric modifications between the two wear surfaces, a new concept, comparative surface harmony (CSH), is developed and a mating index, comparative surface harmony index (CSHI), is formulated to characterize the surface interlocking and wear evolution of the shearing interfaces formed at contact areas between the shoes and floors. A companion paper [Development of a new analyzing model for quantifying pedestrian slip resistance characteristics: Part II - Experimental investigations] presents a study of the model application in a set of slip resistance tests, surface profile analyses and microscopic investigations to verify the outcomes between the theoretical and experimental results.