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A braking control system is an essential part of urban rail vehicle braking systems. Due to the uncertainty of operational data, direct analysis can affect the authenticity of system reliability. To solve the deviation of system reliability analysis caused by uncertainty, GO Methodology is combined with fuzzy theory to establish the GO graph model of the system according to the characteristics of the braking control system. The membership function of the fuzzy success rate of the system is obtained by using the modified signal flow calculation method combined with the fuzzy number algebraic calculation method, and the system fuzzy success rate with high reliability is selected. The calculated results can provide guidance and suggestions for system maintenance, and they have strong engineering practicability. [ABSTRACT FROM AUTHOR]

Contact fatigue is one of the main causes of the failure of gear transmission systems. Considering the gear separation phenomenon, a contact damage-torsional vibration coupling dynamic model is proposed with nonlinear backlash, time-varying meshing stiffness, contact stress model, and contact damage model based on gear contact geometry, S-N curve, and reliability theory. Using the model established, the numerical simulation is investigated to analyze the degradation process of the gear system under a fixed-speed condition. The research results show that the degradation process of gear contact fatigue has a non-linear relation with rotational speed and rotation cycle. The contact stress shows that there is no obvious gear separation phenomenon at n = 1000 and n = 3000, but there are obvious gear separation phenomena at n = 2000. The remaining useful life of gear teeth changes more violently and the total life is lowest at n = 2000. [ABSTRACT FROM AUTHOR]