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Pueblo West, CO, United States

Meymand S.Z.,Virginia Polytechnic Institute and State University | Keylin A.,Transportation Technology Center Inc. | Ahmadian M.,Virginia Polytechnic Institute and State University
Vehicle System Dynamics | Year: 2016

Accurate and efficient contact models for wheel-rail interaction are essential for the study of the dynamic behaviour of a railway vehicle. Assessment of the contact forces and moments, as well as contact geometry provide a fundamental foundation for such tasks as design of braking and traction control systems, prediction of wheel and rail wear, and evaluation of ride safety and comfort. This paper discusses the evolution and the current state of the theories for solving the wheel-rail contact problem for rolling stock. The well-known theories for modelling both normal contact (Hertzian and non-Hertzian) and tangential contact (Kalker's linear theory, FASTSIM, CONTACT, Polach's theory, etc.) are reviewed. The paper discusses the simplifying assumptions for developing these models and compares their functionality. The experimental studies for evaluation of contact models are also reviewed. This paper concludes with discussing open areas in contact mechanics that require further research for developing better models to represent the wheel-rail interaction. © 2016 Taylor and Francis.

Robles Hernandez F.C.,Transportation Technology Center Inc. | Robles Hernandez F.C.,University of Houston | Demas N.G.,University of Illinois at Urbana - Champaign | Gonzales K.,Transportation Technology Center Inc. | Polycarpou A.A.,University of Illinois at Urbana - Champaign
Wear | Year: 2011

Railroads in the United States spend approximately $2.5 billion a year on rail replacement and repairs, making rail the most valuable asset for the railroad industry in North America. The Transportation Technology Centre, Inc. (TTCI) continuously conducts full-scale rail performance tests using the newest generations of premium rails. This in turn allows better understanding of the rail characteristics that require improvements and is used to extend rail's life. Recent research has focused on methods to streamline the developments of prototype rail steels using laboratory tribotests. The results of the tribotests indicate that sliding ball-on-disk experiments can be used to qualitatively approximate rail wear and using scanning electron microscopy (SEM) it is possible to observe different tribological behaviour between rails (mild to severe wear). For instance, SEM micrograph analysis can lead to the determination of the propensity of rail crack formation under pure sliding and the detrimental effects of pro-eutectoid cementite and hard inclusions (e.g., Al2O3) on crack formation and delamination. © 2011.

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