In-Ju Kim

Wear Observation of Shoe Surfaces: Application for Slip and Fall Safety Assessments

Shoe surfaces are continuously changed during pedestrian ambulation. Such changes include significant damage mechanism of shoe soles/heels, but their importance, fundamental perception, and effects on slip-resistance properties have hardly been discussed in the literature. This study aimed to understand wear development on shoe surfaces and identify its impact on pedestrian walkway slip-resistance performance. A wear concept and theory model were suggested to explore the underlying tribological characteristics of the shoe surfaces. Dynamic friction tests were conducted between two double-density polyurethane shoes and ceramic tiles. Wear formation and development on the shoe surfaces were quantitatively and qualitatively examined by surface roughness parameters and microscopic observations before and after the tests. Overall results clearly showed that the topographic structures of the shoe surfaces were largely changed by a series of wear mechanisms such as abrasion, ploughing, adhesion, and fatigue. This study suggests that future research on slip and fall incidents should pay close attention to the issue of the wear behaviors of shoe surfaces and their impact on slip-resistance performance. Findings from this study may have potential implications to improve design concepts for shoe soles/heels in order to reduce slip and fall hazards.

Investigation and Interpretation of Flooring Wear Development for Pedestrian Slip Resistance Assessments

ABSTRACT Surface conditions of pedestrian footpaths and walkways continually change throughout their services. Many causes may contribute to the variation of surface qualities, but a decline of slip resistance functioning is a critical problem for the pedestrian safety of walkway surfaces. Despite the importance of flooring wear issue, their ensured operations and influences on slip resistance performance against pedestrian falls have not been systematically investigated. The present study aims to understand wear progress of floor surfaces, investigate the mechanism of surface changes due to wear advances, and recognize their impacts on slip resistance operations. To measure traction properties and characterize wear behaviors of walkway surfaces, slip resistance tests were operated among three different types of floor specimens with a similar range of topographic characteristics and two dissimilar shoes. Wear formations and developments of the floor specimens were comprehensively assessed by a combination of numerical and microscopic investigations. The test outcomes evidently presented that the initial surface finishes of floor specimens were extensively modified by direct (straight move) and indirect wear processes (reverse and joint moves) and significantly affected slip resistance performance. The idea explored in this study may help to uncover valuable information for better understanding of the complex nature of slip resistance properties amongst the shoes, floors, and environments and have possible applications for the safety design improvements of pedestrian floors and floor coverings.

Investigation of Floor Surface Finishes for Optimal Slip Resistance Performance

Background Increasing the slip resistance of floor surfaces would be desirable, but there is a lack of evidence on whether traction properties are linearly correlated with the topographic features of the floor surfaces or what scales of surface roughness are required to effectively control the slipperiness of floors. Objective This study expands on earlier findings on the effects of floor surface finishes against slip resistance performance and determines the operative ranges of floor surface roughness for optimal slip resistance controls under different risk levels of walking environments. Methods Dynamic friction tests were conducted among three shoes and nine floor specimens under wet and oily environments and compared with a soapy environment. Results The test results showed the significant effects of floor surface roughness on slip resistance performance against all the lubricated environments. Compared with the floor-type effect, the shoe-type effect on slip resistance performance was insignificant against the highly polluted environments. The study outcomes also indicated that the oily environment required rougher surface finishes than the wet and soapy ones in their lower boundary ranges of floor surface roughness. Conclusion The results of this study with previous findings confirm that floor surface finishes require different levels of surface coarseness for different types of environmental conditions to effectively manage slippery walking environments. Collected data on operative ranges of floor surface roughness seem to be a valuable tool to develop practical design information and standards for floor surface finishes to efficiently prevent pedestrian fall incidents.

Wear Progression of Shoe Heels during Slip Resistance Measurements

Predicting changes in slip resistance performance with wear evolution is extremely difficult task and at present neither footwear nor flooring industries have a valid and reliable answer. Hence, in order to gain fundamental knowledge on wear mechanism, progressive wear and surface alteration processes of the shoes are investigated during repetitive dry rubbing. It is assumed that geometry changes of the shoe surface caused by wear development would be a major factor that affects the slip resistance performance. With the measurements of slip resistance, wear characteristics of two different shoes are comprehensively investigated based on the surface analyses and microscopic observations. For the systematic investigation of the surface alterations, topographic changes of each shoe were thoroughly examined on a regular time basis. The results show that surface alterations of each shoe were more severe than expected and occurred from the very early stage of sliding. It is also found that initially unstable friction process changed into the steady state friction process in the later stage of the slip resistance tests.