An Adaptive Contact Model for Simulation of Wheel-rail Impact Load due to a Wheel Flat

J. J. Zhu, A. K. W. Ahmed and S. Rakheja

ABSTRACT: Several reported studies have concluded that wheel-rail impact load due to a wheel flat predicted by commonly used Hertzian contact model underestimates the impact force due to a wheel flat between wheel and rail at low speeds and yields an overestimation at high speeds. In this study, an adaptive wheel-rail contact model with radial spring is developed for prediction of wheel-rail normal contact force. This proposed model adapts the contact length, contact depth and incorporates possible partial and asymmetry of the contact due to defective wheel profile. A vehicle-track interaction model incorporating a 2-D rollplane vehicle, 3-D Timoshenko track system coupled by the adaptive contact model is developed to investigate the impact force between the wheel and rail due to a single wheel flat. The simulation results were compared with those using Hertzian contact model and available field test data. The results demonstrate the effectiveness of the adaptive contact model in predicting wheel rail impact load due to a wheel flat in a wide speed range.

KEYWORDS: Adaptive Contact, Wheel-rail, Wheel Flat, and Impact Load

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