Slip and fall accidents are a serious occupational and public health problem. While shoe-floor-contaminant friction is known to be critical to slip risk, no method of measuring shoe-floor-contaminant friction is widely accepted as being relevant to human slips. In addition, the tribological mechanisms of the shoe-floor-contaminant interface are poorly understood. This dissertation studies slips and falls from a biomechanical and tribological perspective. Heel contact control was investigated during human slipping experiments. Knee joint torques were found to be the primary contributor to heel acceleration during contact with the floor. For the tribology portion of this research, experimental testing was performed using a novel whole shoe slip testing method and a pin-on-disk tribometer. The experiments revealed that shoe-floor-contaminant friction could be described with the theoretical Stribeck curve. The lubrication regime that was determined to be most relevant to shoe-floor-contaminant friction was the mixed-lubrication regime. A computational model was developed to describe this mixed-lubrication regime, simulating the hydrodynamic and contacting pressures at the shoe-floor-contaminant interface applied to pin-on-disk experiments. The model-predicted friction values showed good agreement with experimental data. Because the custom code was limited to simple geometries, FEA was examined for its ability to simulate mixed-lubrication of an entire shoe heel against a floor surface. Limitations were discovered in current FEA software packages that prevented their use in shoe-floor-contaminant friction modeling. Therefore, a hybrid model that used FEA software to simulate the contact and custom modeling to simulate the lubrication effect was proposed. The research presented in this dissertation may be the first step towards developing a comprehensive shoe-floor-contaminant friction model, which will be useful for evaluating slip potential of shoes and flooring, designing safer shoes and floor surfaces, and understanding the biomechanics of slipping.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-12042008-133034 |
| Date | 28 January 2009 |
| Creators | Beschorner, Kurt Edward |
| Contributors | Rakié C. Cham, Ph.D., Richard E. Debski, Ph.D., C. Fred Higgs III, Ph.D., Michael R. Lovell, Ph.D., Mark S. Redfern, Ph.D. |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-12042008-133034/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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