MODELING SHOE-FLOOR-CONTAMINANT FRICTION APPLIED TO A PIN-ON-DISK APPARATUS

摘要

Slip and fall accidents are a serious health problem causing a substantial economic burden throughout the developed world. Fundamental understanding of friction between shoe-floor-contaminant interfaces could be improved with computational models. We present a shoe-floor-contaminant friction model based on mixed-lubrication that utilizes a number of measurable inputs such as sliding speed, vertical force, shoe material information (geometry, roughness and elastic modulus) and fluid viscosity. A multi-scale modelling approach includes asperity contact and hydrodynamic lift. The asperity contact model determines force on the asperities based on film thickness, shoe roughness and shoe elastic modulus. The hydrodynamic lift model determines load carried by the fluid based on the Reynolds equation, geometry of the shoe material, fluid viscosity and sliding speed. A linear rule of mixtures is used to determine coefficient of friction as a function of the load carried by the fluid and by the asperities. Model data show good agreement with experimental data. As sliding speed increases, load is transferred from the asperities to the fluid causing a decrease in friction coefficient. This computational friction model provides valuable information about the interaction of shoe-floor-contaminant surfaces and shows promise for future development into a useful design tool.