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.

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 mm² [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., Changes in under-shoe traction and fluid drainage for progressively worn shoe tread. Applied Ergonomics, 2019. 80: p. 35-42.

[2] Hemler, S.L., D.N. Charbonneau, and K.E. Beschorner, Predicting hydrodynamic conditions under worn shoes using the tapered-wedge solution of Reynolds equation. 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. Wear, 422, pp.235-241.

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.