DOI: 10.5061/dryad.b2rbnzsfh
title: Changes in under-shoe traction and fluid drainage for progressively worn shoe tread

description: Slip and fall accidents are a common cause of injuries in the workplace.
 Slip-resistant footwear offers the potential to reduce the risk
 of these accidents. However, the efficacy of these shoes is reduced as
 shoes become worn. This data set provides the key independent and
 dependent variables from a study to evaluate the changes in traction
 performance of slip-resistant shoes as they become worn. The traction
 performance of five shoes were tracked as these shoes were exposed to
 mechanical wear. The coefficient of friction and under-shoe fluid
 pressures were measured in their baseline condition and after each worn
 iterations. During each wear iterations, shoes were mechanically worn at
 three different angles to simulate the shoe angle progression during the
 weight-acceptance phase of gait. Coefficient of friction was quantified as
 the ratio of friction to normal forces. The peak fluid pressure and the
 fluid force (spatial integral of fluid pressure) were calculated. The worn
 region size of each shoe was measured. This worn region size was applied
 to a tapered wedge bearing model to predict film thickness.
description: Methodological details are available in detail in the following
 publications [1-3]. Details about the variables are provided
 below. Each row
 represents a shoe and a wear cycle. Each shoe was tested at multiple wear
 cycles. Citation
 numbers include the manuscript where this data is reported.
 1. Column A (“Shoe Code”)
 represents the shoe code used [1, 2]. 2. Column B (“Shoe Brand”)
 represents the shoe brand [1]. 3. Column C (“Wear Cycle”)
 represents the cycle number the shoes were abrasively worn down [1, 2].
 The cycle, 0, represents baseline condition. 4. Column D (“Sliding Distance
 [km]”) represents the distance that the shoes were worn on the abrasive
 paper [1]. A distance of 0 represents baseline condition. 5. Column E (“ACOF”) represents
 the average available coefficient of friction from the five trials
 measured for the shoes (tested against a vinyl composite tile with 90%
 glycerol solution contaminant as described in [1]). 6. Column F (“ACOF Standard
 Deviation”) represents the standard deviation of the available coefficient
 of friction between the five slip testing trials [1]. 7. Column G (“Peak Fluid Pressure
 [kPa]”) represents the peak fluid pressure measured between the shoe and
 flooring during friction testing across the five trials. 8. Column H (“Fluid Force [N]”)
 represents the load supported by the fluid during slip testing [1,
 2]. 9. Column I
 (“Fluid Force Category”) represents the fluid force in terms of the
 percentage of the normal force during slip testing [1]. 10. Column J (“Untreaded Length
 [mm]”) represents the length of the continuous worn region along the long
 axis of the shoe (i.e., axis running from the heel to the forefoot)
 [2]. 11. Column K
 (“Untreaded Width [mm]”) represents the width of the continuous worn
 region along the short axis of the shoe (perpendicular to the length)
 [2]. 12. Column L
 (“Worn Region Size [mm^2]”) represents the product of the untreaded length
 and width in mm<sup>2</sup> [1]. This variable is known as
 “untreaded region” in [1]. 13. Column M (“Film Thickness
 [um]”) represents the fluid film thickness in μm [2]. 14. Column N (“Volume Loss
 [mm^3]”) represents the volumetric tread loss relative to the shoe’s new
 condition [3]. 15. Column O (“lambda ratio”)
 represents the dimensionless film thickness as described in [2].
 References: [1] Hemler, S.L., et al., <i>Changes in under-shoe traction and fluid drainage for progressively worn shoe tread.</i> Applied Ergonomics, 2019. 80: p. 35-42. [2] Hemler, S.L., D.N. Charbonneau, and K.E. Beschorner, <i>Predicting hydrodynamic conditions under worn shoes using the tapered-wedge solution of Reynolds equation.</i> Tribology International, 2020: p. 106161. [3] Moghaddam, S.R.M., Hemler, S.L., Redfern, M.S., Jacobs, T.D. and Beschorner, K.E., 2019. Computational model of shoe wear progression: Comparison with experimental results. <i>Wear</i>, <i>422</i>, pp.235-241.
description: Missing data: Note that the size of the worn region
 ("Untreaded Length [mm]" and "Untreaded Width [mm]")
 was calculated using the tread dimensions in the baseline conditions
 ("Wear Cycle" = 0) and then based on the dimensions of the worn
 region once a worn region had formed. For trials after the baseline
 condition but before the development of the worn condition, these tread
 dimensions were not measured again because they would be identical to the
 baseline condition. Worn region size was also not measured for "Shoe
 Code" = A since multiple worn regions formed. Any value calculated
 from the worn region dimensions ("Film Thickness [um]" and
 "lambda ratio") were also not calculated. Other null cells
 reflect missing data from the data set.