Atomic-Scale Tribological Behaviors of Rail-Wheel Interface under Dry Conditions: A Molecular Dynamics Simulation

Abstract The interfacial friction performance of the wheel-rail system is related to the safety of train operation, energy consumption, and maintenance costs. Herein, the atomic models containing ER8 wheels and U71MnG rails are constructed to study the effects of the indentation depth and temperature on interfacial friction characteristics of the wheel-rail interface using molecular dynamics (MD) simulation. The MD results showed that the friction force and diffusion coefficient increase with the increase of indentation depth, accompanying the amount and migration range of wear chips, whereas the average friction coefficient decreases. Within different high-temperature ranges, the average friction coefficient decreases as the temperature increases. The indentation depth and temperature jointly dominate the microscopic wear path of wheel-rail interface friction by regulating lattice distortion, atomic migration and chip formation. This study reveals the interfacial friction mechanism of the wheel-rail system from an atomic perspective, which provides a theoretical basis for optimizing the friction performance of the wheel-rail system.