dc.contributor.author Keylin, Alexander en dc.date.accessioned 2014-07-18T17:32:42Z en dc.date.available 2014-07-18T17:32:42Z en dc.date.issued 2013-01-23 en dc.identifier.other vt_gsexam:144 en dc.identifier.uri http://hdl.handle.net/10919/49607 en dc.description.abstract The primary purpose of this research is to investigate the effectiveness of a scaled roller rig for accurately assessing the contact mechanics and dynamics between a profiled steel wheel and rail, as is commonly used in rail vehicles. The established creep models of Kalker and Johnson and Vermeulen are used to establish correction factors, scaling factors, and transformation factors that allow us to relate the results from a scaled rig to those of a tangent track. ï¿½Correction factors, which are defined as the ratios of a given quantity (such as creep coefficient) between a roller rig and a track, are derived and used to relate the results between a full-size rig and a full-size track. Scaling factors are derived to relate the same quantities between roller rigs of different scales. Finally, transformation factors are derived by combining scaling factors with correction factors in order to relate the results from a scaled roller rig to a full-size tangent track. Close-end formulae for creep force correction, scaling, and transformation factors are provided in the thesis, along with their full derivation and an explanation of their limitations; these formulae can be used to calculate the correction factors for any wheel-rail geometry and scaling.For Kalker\'s theory, it is shown that the correction factor for creep coefficients is strictly a function of wheel and rail geometry, primarily the wheel and roller diameter ratio. For Johnson and Vermeulen\'s theory, the effects of creepage, scale, and load on the creep force correction factor are demonstrated. ï¿½It is shown that INRETS\' scaling strategy causes the normalized creep curve to be identical for both a full-size and a scaled roller rig. ï¿½It is also shown that the creep force correction factors for Johnson and Vermeulen\'s model increase linearly with creepage, starting with the values predicted by Kalker\'s theory. ï¿½Therefore, Kalker\'s theory provides a conservative estimate for creep force correction factors. ï¿½A case study is presented to demonstrate the creep curves, as well as the correction and transformation factors, for a typical wheel-rail configuration. ï¿½Additionally, two studies by other authors that calculate the correction factor for Kalker\'s creep coefficients for specific wheel-rail geometries are reviewed and show full agreement with the results that are predicted by the formulae derived in this study. ï¿½Based on a review of existing and past roller rigs, as well as the findings of this thesis, a number of recommendations are given for the design of a roller rig for the purpose of assessing the wheel-rail contact mechanics. ï¿½A scaling strategy (INRETS\') is suggested, and equations for power consumption of a roller rig are derived. Recommendations for sensors and actuators necessary for such a rig are also given. Special attention is given to the resolution and accuracy of velocity sensors, which are required to properly measure and plot the creep curves. en dc.format.medium ETD en dc.publisher Virginia Tech en dc.rights In Copyright en dc.rights.uri http://rightsstatements.org/vocab/InC/1.0/ en dc.subject roller rigs en dc.subject wheel-rail contact en dc.subject friction modeling en dc.subject normal contact en dc.subject tangent contact en dc.subject rolling contact en dc.title Analytical Evaluation of the Accuracy of Roller Rig Data for Studying Creepage in Rail Vehicles en dc.type Thesis en dc.contributor.department Mechanical Engineering en dc.description.degree Master of Science en thesis.degree.name Master of Science en thesis.degree.level masters en thesis.degree.grantor Virginia Polytechnic Institute and State University en thesis.degree.discipline Mechanical Engineering en dc.contributor.committeechair Ahmadian, Mehdi en dc.contributor.committeemember Taheri, Saied en dc.contributor.committeemember Sandu, Corina en
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