【作者】 高广军；

【导师】 田红旗；

【作者基本信息】 中南大学 ， 载运工具运用工程， 2008， 博士

【摘要】 强侧风作用下,列车在特大桥梁、高路堤或风口线路上极有可能造成列车倾覆等重大行车事故。对强侧风作用下列车运行安全性进行研究,找出车辆在强风作用时的倾覆机理,并找出具体防范措施,对于预防大风事故的发生,确保铁路运输的正常进行具有重要的现实意义。从车速—风速—线路—车辆耦合情况下车辆的气动性能出发,建立了车辆在瞬态突变载荷和稳态载荷下车辆在轨道上倾覆以及车体在转向架上倾覆的数学模型,最终得出了列车在不同载重、不同线路条件(路堤或桥梁)下风速与临界车速的关系,并提出了提高车辆在强侧风下运行的安全措施,完整地建立了在风—车—路三者耦合条件下研究车辆行车安全性的方法体系。较为系统地、完整地建立了采用不同结构形式的转向架(一系或二系悬挂、钢簧或空气弹簧、摆式或非摆式转向架、有无摇动台等)的车辆在强突变风载荷及稳态风载荷情况下车辆在轨道上倾覆、车体在转向架上倾覆的数学模型。研究表明:车辆在突变载荷情况下更容易发生倾覆事故;列车的倾覆不仅与列车在运行中的受力有关,还与车体与转向架之间的相对位置有关;车体与转向架之间发生振动时的相对横向偏移量越小,则车辆越不容易发生倾覆。得到了在强侧风作用时车—路耦合条件下车辆的气动性能。研究表明:车辆受到的气动力均随着车速和风速的增大而增大,在风向角为90°左右时,车辆受到的气动力最大;在同样外界条件(车速、风速和风向角)的情况下,车辆受到的气动力均随着路堤和桥梁高度的增高而增大;路堤迎风面结构形式对车辆的气动性能影响较小,但背风面的结构形式对列车气动性能影响较大,随着路堤背风面斜率的增大,车辆受到的气动力显著减小;对在峡谷中桥梁上的车辆来说,同样标准风速情况下,两座山之间的间距越短,列车受到的气动力越大。得到了风—车—路三者耦合条件下车辆的速度限值。研究表明:棚车和集装箱车的外形流线化最差,在同样风速条件下会承受较大的气动力,车辆的临界运行车速较低,而罐车的流线型外形最好,在同样风速时受到的气动力较小,则车辆的临界运行车速相对较高;车辆的自重越大,其临界允许车速就越高;随着桥梁和路堤的增高,车辆的临界车速迅速下降,若在线路上加挡风墙,则可以有效降低车辆受到的气动力,进而提高车辆的临界运行车速;车辆在曲线上运行时由于受离心力的影响,其临界车速会迅速降低;车辆的重心越高,则相同的离心力会产生较大的倾覆力矩,降低车辆的临界运行车速;横向振动惯性力对系统影响较大,加装阻尼器、改善踏面形状等可有效的降低振动的频率和幅值,进而降低横向振动加速度,最终提高车辆的临界运行车速。根据对单节车的研究结果,给出了一列车的限速准则:即整列车所处的位置中的所有危险点上、所有车辆的最小的临界运行车速为列车的限速。提出了大风对行车安全影响因素的改善措施。对车辆自身而言,降低车辆重心高、降低车辆在运行时的横向振动加速度能提高车辆在强侧风下的临界倾覆风速。但根本上来说,降低车辆在强侧风下受到的气动力能有效的提高车辆的抗倾覆性能,主要措施为改善车辆在强侧风下的气动外形、在线路上加设挡风墙。以棚车为例给出了棚车在强横风作用时的最佳侧壁及车顶的外形轮廓;给出了路堤上采用不同类型的挡风墙时挡风墙的最优参数;给出了桥梁上单侧透风式挡风墙最佳结构参数(挡风墙高度、透风率、挡风墙位置)。提出了风区风速的预测方法。即针对原始风速时间序列,首先进行滑动平均,然后采用卡尔曼滤波求出真值,最后采用时间序列或神经网络的方法建立风速的预测模型。时间序列预测主要针对单个测点,该方法需要较多的历史数据,能够对将来很好的预测,并能给出预测误差。针对距离较近、风速相关性较强的几个测点,可以采用神经网络预测的方法,这种方法充分考虑系统的非线性,采用较少的历史数据就能给出比较精确的预测。更多还原

【Abstract】 Serious accidents such as train capsizing always happened in special areas such as large bridge and high embankment and railway line in wind region under strong side wind. It is significantly important to ensure the safety of railway transportation by researching on the train operation safety under strong side wind and by finding the mechanism of train capsizing under strong side wind and at the same time by finding the solid protecting measurement.Start from researching the train aerodynamic under the situation that wind speed and train speed and railway line and vehicle coupled together, set up the math model of train capsizing on rail and model of carboy capsizing on bogie when train bearing transmit load or steady load, and get the relation between wind speed and critical train speed when train in different load condition and different railway situation. Based on the method related above, a method system on train safety has been set up fully under the situation that wind and train and railway line coupling together.Math model of train capsizing on track and carboy capsizing on bogie bearing transmit load or steady load has been built systematically and fully when train using different structure bogie, such as one suspension or two suspensions , steel spring or air spring, pendulum bogie or normal bogie, with or without shaker. The results show that the probability of capsizing is large when train bearing transmit load, and that train’s capsizing not only relate to loads train bearing but also relate to relatively location of bogie and carboy. If the relative displacement between bogie and carboy is smaller, the train will be hard to capsize.Train aerodynamic performance is gotten. The results show that: aerodynamic forces of train bearing increase when wind speed or train speed increasing and that when wind angle is near 90 degree the aerodynamic forces are largest. In the same situation (wind speed and train speed and wind angle) aerodynamic forces improve with the increasing of height of bridge or embankment, structure of windward surface of embankment effect lightly to train’s aerodynamic performance while structure of leeward surface effects significantly to train aerodynamic performance and train’s aerodynamic forces decrease significantly when slope of leeward surface of embankment improves. To train in bridge in gorge train aerodynamic forces improve if the distance between the two hills decreases at the same wind speed.The limit value of train critical speed under the situation is gotten when wind speed and vehicle and railway line coupled together. Results as follow: the figure of box car and container car is almost not streamlined and they will bear large aerodyne forces and so the train critical speed is lower, while the figure of tank car is better waterline and it will bear little aerodynamic force at the same wind speed, so train’s critical speed is higher. Train critical speed will decrease when height of bridge and embankment improves while the train critical speed can be improved if installing wind fence in railway line to decreasing the aerodynamic force, train critical speed will decrease sharply when train is running in curve line for the huge centrifugal force. Higher the center of gravity of train and higher the capsizing moment in same centrifugal force and which will decrease train critical speed. Lateral inertia force has significant influence to the whole system and installing dampers in bogie and reforming tread figure can effectively slow down the frequency and range of lateral vibration and can slow down acceleration of lateral vibration which will improve train critical speed. Based on the results of a single car, a speed limiting law of a train is put forward at last that the limiting speed value is the smallest train critical speed of the whole train in all dangerous point and the smallest train critical speed of all the single train.The reformed measurement is put forward to ensure train operation safety. To the train, decreasing its height of center of gravity and minimizing its lateral vibrating acceleration when in operation can improve train critical speed under strong side wind. But fundamentality speaking, reducing the aerodynamic force under strong side wind can improve train speed significantly, and the main measurements is to reform the train’s figure and to set up wind fence in railway line. Taking box car for example the best aerodynamic figure of side wall and ceiling is given when train bearing strong side wind. Put forward the optimization parameters of all the types of wind fence in embankment. Put forward the optimization parameters such as height of wind fence and wind leaking ratio and its location of single side wind fence in bridge.The prediction model of wind speed is put forward in wind region. Pointing to the initial wind speed time serial, the first step is to average the initial data using moving average model, then get the true data using Kalman filter, the last is to built the wind prediction model using wind data serial or Neural Networks. Wind speed data serial prediction model is mainly pointing to the single point and predictes well and can also give the prediction error but need much more history data. Pointing to adjacent measurement points whose wind speeds correlating strongly, Neural Networks prediction model can be used which considers the nonlinear of the whole system fully and can give precious precision only using little history data.更多还原