• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2023, Vol. 59 ›› Issue (10): 210-225.doi: 10.3901/JME.2023.10.210

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Research on Stability and Bifurcation of Nonlinear Stochastic Dynamic Model of Wheelset

WANG Peng1,2, YANG Shaopu1,2, LIU Yongqiang1,3, LIU Pengfei1, ZHAO Yiwei1,2, ZHANG Xing1,2   

  1. 1. State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang Tiedao University, Shijiazhuang 050043;
    2. School of Traffic and Transportation, Shijiazhuang Tiedao University, Shijiazhuang 050043;
    3. School of Mechanical Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043
  • Received:2022-10-12 Revised:2023-03-01 Online:2023-05-20 Published:2023-07-19

Abstract: Aiming at the stochastic dynamics of the wheelset system, considering the influence of the stochastic factors of the equivalent conicity and suspension stiffness, a wheelset model of nonlinear wheel-rail contact relationship with gyroscopic effect is established to investigate the stochastic stability and stochastic Hopf bifurcation of the wheelset system. The stochastic average method transforms the wheelset system into a one-dimensional diffusion process. By judging the behavior of the singular boundary, the stochastic instability conditions and critical speed of the wheelset system are obtained. The stationary probability density function and the joint probability density function are derived theoretically. The topological structure evolution of the probability density function is analyzed, and the type of stochastic Hopf bifurcation of the wheelset system is determined. The influence of stochastic factors on the critical speed of instability and the Hopf bifurcation region is explored. The simulation results verify the correctness of the theoretical analysis. The results reveal that the stochastic stability of the wheelset system is determined by the boundary behavior of the diffusion process, and the left boundary eigenvalue cL=1 is the critical state of stochastic instability. After considering the stochastic factors, the steady-state probability density function of the wheelset system has two qualitative changes with the increase of the bifurcation parameters, which correspond to the stochastic D bifurcation and stochastic P bifurcation of the wheelset system respectively, and the critical speeds of the two stochastic bifurcations decrease with the increase of the random parameter intensity.

Key words: stochastic system, stochastic average method, singular boundary, hunting stability, stochastic bifurcation

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