Influence of averaging time-interval on shoe-floor-contaminant available coefficient of friction measurements

Abstract

Available coefficient of friction (ACOF) is a common metric of footwear traction performance. ACOF is the ratio of friction to normal force, often averaged over a time-interval. The timeinterval needed to achieve repeatable and valid ACOF is unknown. A post-hoc analysis was performed on nine shoe-floor-contaminant combinations to assess the repeatability and bias of data averaged across 4 time-intervals (2 ms, 50 ms, 100 ms, 200 ms) after the target normal force was reached. The ability to predict human slips was assessed for ACOF across these intervals. Differences in repeatability and validity across the four intervals were small. However, statistically significant differences were observed for the shortest compared with the longest interval (lower repeatability yet modestly improved predictive ability). Given the limited impact of time-interval on the results, a shorter interval of 50 ms is recommended to enable testing of smaller floor samples.

An alternative method for analyzing the slip potential of workers on sloped surfaces

“…Other factors such as a wet roof condition, temperature, friction direction, footwear orientation, individual weight and load may also affect the dynamic CF. Unfortunately, although several methods and devices for the CF measurement have been developed and extensive studies have reported the footwear CFs on various floors (Chang et al, 2016;Gronqvirst et al, 1989;Pollard et al, 2015;Beschorner et al, 2019Beschorner et al, , 2020, a systematical investigation on the dynamic CF under these conditions has not been reported in a sloped roofing environment. This is obviously an urgent and important research project.…”

Relationship between Friction Coefficient and Surface Roughness of Stone and Ceramic Floors

“…Measurements of both the required and available COF are complicated. The former requires the recruitment of human participants and the use of one or more force platforms so as to analyze the ground reaction force of the foot on the floor [12,13]. The latter, on the other hand, requires the use of a friction measurement device, also called a tribometer or a slipmeter, to measure the COF of the floor under certain footwear and floor conditions [9,14].…”

“…Studies testing the effects of the floor, footwear, floor inclined angle, and floor surface contaminations on slipperiness have been reported [14,18,[23][24][25][26][27][28][29][30][31][32]. There were also studies comparing the testing parameters, test methods, reliability, and validity of friction measurement devices [13,17,[32][33][34][35].…”