Development of a Portable Device for Surface Traction Characterization at the Shoe–Floor Interface

Abstract

Slip and fall accidents are widespread in workplaces and on walkways. Slipping is generally initiated by a sudden change in the flooring properties or due to a low available traction at the shoe–floor interface. To measure shoe-floor traction, mechanical slip and fall risk estimation devices are typically employed. However, to date, such existing devices are lab-based, bulky, and are unable to simulate realistic slip biomechanics and measure whole footwear traction in realistic contaminated floorings at the same time. Moreover, these devices are expensive and not available in low- or lower-middle-income countries with limited awareness regarding slip testing. To overcome these challenges, in this work, a biofidelic, portable, and low-cost slip testing device was developed. A strategic three-part subassembly was designed for the application of normal load, slipping speed, and heel strike angle for its modularity. The developed slip tester was extensively tested and validated for its performance using 10 formal footwears and two floorings, under dry and wet conditions. The results indicated that the slip tester was accurate, repeatable, and reliable in differentiating traction measurements across varying combinations of shoes, contaminants, and floorings. The instrumentation performance of the slip tester was found to also capture the differences between different shoe tread patterns in the presence of fluid films. The developed device is anticipated to significantly impact the clinical, industrial, and commercial performance testing of footwear traction in realistic slippery flooring conditions, especially in the low- or middle-income countries.

Traction performance modeling of worn footwear with perpendicular treads

“…In this case, 40% of the outsoles showed dry friction values below the threshold of 0.3. This consideration was in-line with several other works, based on footwear slipping, in literature [7,9,[32][33][34]. As per the wear protocol considered in our work, the second wear cycle corresponded to simulated 6 months of wear.…”

“…The device running and testing was based on the ASTM F2913-19 guidelines [31] which represents the testing framework to assess the shoe-floor friction mimicking actual human slips. The detailed design and development of the implemented device is presented in a recent work by Gupta et al [32,33]. The device was found to be biofidelic and repeatable [34].…”

Influence of Vertically Treaded Outsoles on Interfacial Fluid Pressure, Mass Flow Rate, and Shoe–Floor Traction during Slips

“…Figure 3 represents the consolidated computational framework, and Table 2 represents the summary of the CFD parameters based on a recent study by Gupta et al [30]. The shoe-floor traction was estimated using a portable and biofidelic mechanical slip tester [31] (Figure 4). The whole-shoe slip-testing device implemented in this study was based on the ASTM F2913-19 standard [32].…”

“…Finally, the dynamic friction was calculated by dividing the shear force by the normal force observed during the slipping simulation. The detailed development of this device is explained in a recent work by Gupta et al [31]. The developed outsoles were then attached to the footwear, and the footwear was further attached to the slip tester.…”

“…Five repetitions for each sample across each slipping condition (i.e., dry and water contaminant condition) were performed separately and represented. The ACOF values were quantified within the initial 200 ms once the normal load reached 250 ± 25 N. The shoe-floor traction was estimated using a portable and biofidelic mechanical slip tester [31] (Figure 4). The whole-shoe slip-testing device implemented in this study was based on the ASTM F2913-19 standard [32].…”