摘要
针对车轮型面动态变化下的轨顶/轨侧摩擦系数匹配问题,跟踪测试2条线路在不同服役阶段下的车轮磨耗型面数据,建立地铁车辆动力学模型,分析车轮型面动态变化下轨顶/轨侧摩擦系数匹配对轮轨磨耗性能、轮对冲角、表面疲劳指数和脱轨系数的影响;以上述4个指标建立基于熵权TOPSIS法的多目标优化模型,得到轨顶/轨侧摩擦系数最佳匹配策略.研究发现:随车轮型面动态变化,轮缘磨耗型面和踏面磨耗型面的轮轨接触点发生不同程度的跳跃与集中,轮轨匹配关系恶化;轮缘磨耗型面在服役初期的综合性能主要受轨顶摩擦系数影响,随服役里程增加,轨侧摩擦系数的变化占据主导地位;踏面磨耗型面的综合性能指标主要受轨顶摩擦系数的影响;在车轮服役初始阶段、磨损早期、磨损中期、磨损晚期阶段,轮缘磨耗型面车轮对应的轨顶/轨侧最佳摩擦系数匹配分别为0.30/0.10、0.25/0.10、0.20/0.10和0.20/0.10,踏面磨耗型面车轮对应的轨顶/轨侧最佳摩擦系数匹配分别为0.20/0.15、0.20/0.30、0.20/0.35和0.30/0.15.
Abstract
Aiming at the dynamic changes in wheel profiles,the optimal rail top/side Friction Coefficient Combinations(FCCs)for wheels with worn flange and worn tread profiles in different service stages were explored separately.Wheel profile wear data was tracked along two subway lines as the distance traveled increased.A dynamic model of subway vehicle was construc-ted to analyze the effects of rail top/side FCCs on wheel-rail wear properties,attack angle of wheelset,surface fatigue index and derailment coefficient,with the dynamic changes in wheel profiles taken into account.Then a multi-objective optimization model was developed based on the entropy-weighted TOPSIS method,which includes the four performance indicators mentioned above as the criteria.Finally,the optimal FCCs were obtained.The results suggest that as wheel profiles dynamically change,the wheel-rail contact points show sudden changes in position and tend to concentrate to varying degrees,resulting in poorer match between wheels and rails.The comprehensive performance of worn flange profiles is affected primarily by rail top friction coefficient during initial operation.As the distance traveled increases,the rail side friction coefficient predominates.The comprehensive performance of worn tread profiles is influenced mainly by rail top friction coefficient in all stages of wheel service.During the stages of initial operation,early wear,middle wear,and late wear,the optimal rail top/side FCCs for wheels with a worn flange profile are 0.30/0.10,0.25/0.10,0.20/0.10,and 0.20/0.10,respectively.For wheels with a worn tread profile,these are 0.20/0.15,0.20/0.30,0.20/0.35,and 0.30/0.15,respectively.
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