ISSN   1004-0595

CN  62-1224/O4

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基于轮瓦非均匀接触压力的重载列车踏面制动温度预测方法

Temperature Prediction Method of Heavy-Haul Trains Tread Braking Based on Non-Uniform Contact Pressure Between Wheel and Brake Shoe

  • 摘要: 重载列车踏面制动过程中,车轮-闸瓦摩擦热直接影响其磨耗及服役寿命,进而影响列车制动安全. 由于重载列车踏面制动复杂几何界面接触及摩擦特性,轮瓦摩擦热分布特性复杂且随接触及摩擦状态变化而变化,现有方法难以准确预测. 为此,基于车轮踏面真实廓形及其匹配的闸瓦廓形,改进了考虑轮瓦接触状态的摩擦热流密度计算方法,以模拟轮瓦不同接触位置的摩擦热特性. 进一步,结合有限元方法及热力学理论,提出1种考虑轮瓦非均匀接触压力的温度预测方法,并通过台架试验进行验证,实现了不同制动工况下轮瓦温度场预测. 基于此,系统分析了所提出方法与传统(均匀接触压力)方法在不同制动工况下计算结果的差异. 结果表明,所提出方法能够更加准确地预测轮瓦温度演变规律及温度场分布特性. 传统方法能够较好地预测车轮最高温度,而难以准确反映闸瓦的最高温度,也难以反映实际制动过程中轮瓦温度分布. 因此,在重载列车踏面制动温度及其相关分析中,需要考虑轮瓦实际接触状态带来的非均匀接触压力特性,以保障结果的可靠性和准确性.

     

    Abstract:
    During the tread braking of heavy-haul trains, the frictional heat generated between the wheel and brake shoe directly impacts their abrasion and service life, thereby influencing the safety of train braking operations. It is necessary to effectively predict the tread braking temperature distribution of the of heavy-haul trains. The wheel-brake shoe interface of heavy- haul trains tread braking involves intricate geometric contact and frictional characteristics, leading to a complex distribution of frictional heat on the wheel and brake shoe that changes with variations in contact and frictional states. Existing methods have demonstrated limitations in effectively predicting the complex distribution of frictional heat.
    To address this challenge, a sophisticated approach had been developed based on the actual profiles of the wheel tread and its corresponding brake shoe profile. This method modified the calculation of frictional heat flux density by considering the contact state between the wheel and brake shoe, enabling the simulation of frictional heat characteristics at various contact positions along the wheel and brake shoe interface. Furthermore, through the integration of finite element methods with thermodynamic principles, a novel temperature prediction method had been proposed. This method took into account the non-uniform contact pressure between the wheel and brake shoe, which was verified by bench test, and the temperature field prediction of the wheel and brake shoe under different braking conditions was realized.
    Building on this foundation, a comprehensive analysis had been conducted to compare the results obtained using the proposed method with those derived from traditional method (which assume uniform contact pressure). The results demonstrated that the proposed method was capable of more accurately predicting the temperature evolution and distribution characteristics of the wheel and brake shoe. In contrast, traditional methods may effectively predict the highest temperature of the wheel, while often struggle to accurately reflect the highest temperature of the brake shoe or capture the actual temperature distribution of both components during the braking process.
    Therefore, in analyzing tread braking temperatures and associated subjects (thermal stress, thermal cracking, and thermal fatigue, et, al) in heavy-haul trains, it was crucial to consider the non-uniform contact pressure resulting from the actual contact state between the wheel and brake shoe. This consideration ensured the reliability and accuracy of the results, ultimately enhancing the safety and efficiency of train braking systems. In conclusion, the development of this method represented a significant advancement in the field of train braking safety. By accurately predicting temperature distributions and considering non-uniform contact pressures, the proposed method held promise for improving the design and operation of braking systems for heavy-haul trains, ultimately contributing to enhanced safety and reliability in rail transportation.

     

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