On the formation mechanism of subway wheel polygons based on wheel-rail stick-slip characteristics

Purpose This study, based on long-term tracking tests of wheel polygon in subway vehicles, aims to reveal the formation mechanism of the eighth-order wheel polygon. Design/methodology/approach This study develops vehicle-track system rigid-flexible coupled dynamics model and wheel-rail contact model. By examining stick-slip vibrations at the wheel-rail interface, this paper reveals the formation mechanism of wheel polygons on the test vehicle. In addition, a method is proposed to quantify wheel-rail stick-slip vibration intensity using the coefficient of variation, which allows for the evaluation of how track conditions influence wheel-rail stick-slip characteristics. Findings Results show that small-radius curves trigger wheel-rail stick-slip vibration, exciting the wheelset torsional mode and causing eighth-order polygonal wear. Track irregularities amplify vibration intensity in the inner wheel, resulting in higher levels of polygonal roughness. Originality/value Through the integration of field measurements and numerical simulations, the intrinsic relationship between wheel-rail interface stick-slip characteristics and the formation of wheel polygon is revealed. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2025-0013/