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Keywords: wheel profile evolution, switch rails, equivalent conicity, Hopf bifurcation, hunting stability, subcritical instability.

Abstract

Turnout zones, characterized by intricate wheel-rail contact geometry and dynamic load transfer, represent critical weak sections influencing vehicle running stability. With the continuous accumulation of service mileage in high-speed railways, wheel profile wear has become increasingly prominent, significantly altering wheel-rail contact relationships, especially in turnout areas, which may exacerbate nonlinear dynamic behavior and induce hunting instability. Focusing on the characteristic switch rail profile, this study establishes a nonlinear single-wheelset dynamic model incorporating equivalent conicity and flange forces, based on long-term field measurements of LMA-type wheel wear profiles. The Hopf bifurcation characteristics are systematically analyzed under different service mileages. Results show that increased mileage leads to a significant rise in equivalent conicity and a substantial reduction in bifurcation speed, dropping from 86.92 m/s at 50,000 km to 40.10 m/s at 200,000 km. Concurrently, the bifurcation type transitions from supercritical to subcritical, shifting the instability mechanism from continuous oscillation to a discontinuous jump-type phenomenon with hysteresis. Two-parameter bifurcation analysis further reveals that suspension stiffness and creep coefficients jointly govern the boundary of bifurcation types, which migrates systematically with wear progression. This study aims to elucidate the mechanisms by which wheel profile evolution dictates the nonlinear bifurcation behavior in turnout zones. It establishes a robust theoretical foundation and a bifurcation-oriented framework for optimizing switch-rail profiles, matching suspension parameters, and implementing mileage-dependent stability management throughout the operational lifecycle.

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Front Page Browse CCC CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Conferences ISSN 2753-3239 CCC: 15 PROCEEDINGS OF THE SEVENTH INTERNATIONAL CONFERENCE ON RAILWAY TECHNOLOGY: RESEARCH, DEVELOPMENT AND MAINTENANCE Edited by: J. Pombo Paper 6.2 Impact of Wheel Wear on the Nonlinear Bifurcation Mechanism of Wheelset Hunting Under the Characteristic Switch-Rail Profile T. Li, J. Xu and P. Wang , Southwest Jiaotong University, Chengdu, People’s Republic of China doi:10.4203/ccc.15.6.2 Full Bibliographic Reference for this paper T. Li, J. Xu, P. Wang, "Impact of Wheel Wear on the Nonlinear Bifurcation Mechanism of Wheelset Hunting Under the Characteristic Switch-Rail Profile", in J. Pombo, (Editor), "Proceedings of the Seventh International Conference on Railway Technology: Research, Development and Maintenance ", Civil-Comp Press, Edinburgh, UK, Online volume: CCC 15, Paper 6.2, 2026, doi:10.4203/ccc.15.6.2 Keywords: wheel profile evolution, switch rails, equivalent conicity, Hopf bifurcation, hunting stability, subcritical instability. Abstract Turnout zones, characterized by intricate wheel-rail contact geometry and dynamic load transfer, represent critical weak sections influencing vehicle running stability. With the continuous accumulation of service mileage in high-speed railways, wheel profile wear has become increasingly prominent, significantly altering wheel-rail contact relationships, especially in turnout areas, which may exacerbate nonlinear dynamic behavior and induce hunting instability. Focusing on the characteristic switch rail profile, this study establishes a nonlinear single-wheelset dynamic model incorporating equivalent conicity and flange forces, based on long-term field measurements of LMA-type wheel wear profiles. The Hopf bifurcation characteristics are systematically analyzed under different service mileages. Results show that increased mileage leads to a significant rise in equivalent conicity and a substantial reduction in bifurcation speed, dropping from 86.92 m/s at 50,000 km to 40.10 m/s at 200,000 km. Concurrently, the bifurcation type transitions from supercritical to subcritical, shifting the instability mechanism from continuous oscillation to a discontinuous jump-type phenomenon with hysteresis. Two-parameter bifurcation analysis further reveals that suspension stiffness and creep coefficients jointly govern the boundary of bifurcation types, which migrates systematically with wear progression. This study aims to elucidate the mechanisms by which wheel profile evolution dictates the nonlinear bifurcation behavior in turnout zones. It establishes a robust theoretical foundation and a bifurcation-oriented framework for optimizing switch-rail profiles, matching suspension parameters, and implementing mileage-dependent stability management throughout the operational lifecycle. download the full-text of this paper (PDF, 14 pages, 1068 Kb) go to the previous paper go to the next paper return to the table of contents return to the volume description
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