高速列车吸能结构研究与明线交会安全评估

发布时间：2018-05-05 15:41

本文选题：高速列车 + 耐撞性设计　；参考：《中国科学技术大学》2014年博士论文

【摘要】：随着高速列车在我国的迅速发展,铁路安全的问题越来越受到关注,尤其是高速运行的列车一旦发生撞击事故,所导致的人身伤害和财产损失无法估量。欧美发达国家于20世纪90年代开始,开始对车辆碰撞展开大量研究。我国铁道部也联合部分高校、研究所等成立了引进技术消化吸收再创新技术研究组。已有的研究表明,当一列高速列车发生撞击时,头部首先参与冲击过程,力沿着牵引梁再传入边梁形成一个力的传导结构。同时由于撞击是冲击载荷,产生的应力波会传向后方并发生多次反射透射。由于车体内部结构非常复杂,因此应力波的传播过程也非常复杂。高速列车在正常运行时,需要有足够的刚度,并满足规范规定的刚度和强度要求,当撞击发生时,为了减轻碰撞事故造成的损失,实现被动安全保护,因此需要研究和设计出针对高速列车自身特点的吸能缓冲结构。理想的车辆吸能结构应当位于车体的前后部分,在可控制的变形区域内发生塑性变形,吸收撞击动能,同时保障乘客区域不发生严重破坏,并且在碰撞过程中不会产生过大的撞击力峰值,使撞击减速度在人体的承受范围内。本文结合具体实验研究,在原有车辆基本承载结构不进行大改动的前提下,新增了以薄壁圆管填充泡沫铝为主体的专用吸能结构。通过有限元模拟,对原有车型和改进后的车型进行了耐撞性分析和比较,根据数据比较和分析,得出改进增加的吸能结构在缓冲吸能方面的优势,并为车辆的实际生产应用提供理论指导。高速列车在实际运行情况下,由于交会,会在两车之间产生一列移动的载荷压力波,该瞬态载荷波的波长、幅值等物理特征由列车的交会速度、线间距、车头的几何形状等因素决定,现有的研究表明,由于交会压力波的作用,会对高速行驶列车的安全性和平稳性带来影响。本文采用多体动力学的方法建立了高速列车中间车厢的模型,并将移动载荷波简化为作用在列车质心的力和力矩,通过比较相同运行速度下,单车行驶和等速明线交会的,车体摆动、轮轴横向力、脱轨系数、轮重减载率等列车安全性能指标,说明明线交会所产生的压力波对高速列车运行安全性所带来的影响。本文建立了某型高速列车头车的有限元模型。数值模型为车头以v=10m/s和20m/s的初始速度撞击刚性墙(相当于列车以72km/h和144km/h的运行速度追尾一列相同的静止列车),由于该种动车的日常行驶速度为200km/h以下,因此此种撞击速度已经足够满足安全条件。车钩在列车起动及刹车时,会吸收一部分能量,但是相对于本次仿真系统的撞击能量,车钩吸收的能量较小,并在较短的时间内脱落,对耐撞性分析影响很小,因此忽略车钩在撞击事件中的作用。计算中事件时长为300ms。通过耐撞性分析得到原有承载吸能结构牵引梁的吸能时程曲线刚性墙撞击反力以及车体破坏情况。通过数值模拟发现,原有的结构吸能部件牵引梁在撞击发生时,主要发生欧拉失稳,不利于能量的吸收和冲击力的缓冲,因此结合实验,针对只能对原有车辆设计做局部改进以及车体不加长的实际情况,提出了四种改进方案,将牵引梁的主体部分有原来的方管结构改为有圆角的方管,并在前端共轴位置增加具有同样结构的吸能管。通过数值计算得到了四种方案两种撞击速度下牵引梁吸能曲线和刚性墙反力曲线,并比较了四种改进方案的吸能性能和四种方案下主要吸能结构的变形模式和吸能规律。结果发现最好的改进方案在10m/s的速度下,可以使吸能相对原设计提高322%,反力峰值降低12%；在20m/s速度下,吸能提高288%,反力峰值降低36%,效果显著。采用多体动力学方法模拟了高速列车中间车厢在六种等速(250～500km/h)明线交会时产生的压力波和德国高速低干扰轨道谱的共同作用下的动态响应过程,得到车体自由度(横摆、侧滚、摇头)、轮轴横向力、脱轨系数和轮重减载率随时间的变化曲线,并与相应车速下未受交会压力波作用的单车行驶时的结果进行对比。结果表明,除轮重减载率以外,列车的其余各项安全指标均满足要求,其中轮轴横向力与脱轨系数两项指标均达到优秀标准,而车体的自由度和轮重减载率受交会压力波的影响明显。明线交会时车体的横摆和摇头远超过单车行驶情况。400km/h以上速度时,轮重减载率严重超标。相比欧美国家对轮重减载率指标的安全标准,我国对动态轮重减载率的标准过于保守,可以适当放宽,并增加超限的持续作用时间的限制。高速列车的安全评估中应考虑交会压力波的影响。
[Abstract]:With the rapid development of high speed trains in our country, the problem of railway safety is getting more and more attention, especially when the high-speed train has an impact accident, the personal injury and property loss can not be estimated. The developed countries of Europe and America began to carry out a lot of research on vehicle collision in 1990s. When a high-speed train strikes, the head first participates in the impact process and forces the force along the traction beam to form a force conduction structure. At the same time, the stress waves generated by the impact are impact loads, and the stress waves will be transmitted. The transmission process of the stress wave is also very complicated because the internal structure of the car body is very complex. The high speed train needs sufficient stiffness when it runs normally and meets the requirements of the stiffness and strength specified in the specification. When the collision occurs, it can reduce the loss caused by the collision accident and realize the passive safety. It is necessary to study and design the energy absorption buffer structure for the characteristics of the high speed train. The ideal vehicle energy absorption structure should be located in the front and back parts of the car body, plastic deformation in the controllable deformation area, the absorption of impact kinetic energy, and no serious damage to the passenger area, and it will not produce in the process of collision. In this paper, a special energy absorption structure with thin circular tubes filled with aluminum foam is added to the original vehicle's basic bearing structure. The analysis and comparison of the impact resistance are carried out. According to the comparison and analysis of the data, the advantages of the improved energy absorption structure in the buffer energy absorption are obtained, and the theoretical guidance for the actual production and application of the vehicle is provided.
In the actual operation of a high speed train, a moving load and pressure wave will be produced between the two vehicles due to the intersection. The physical characteristics of the transient load wave, such as the wavelength and amplitude, are determined by the speed of the train, the distance between the lines, the geometry of the head and so on. The existing research shows that the high speed will be driven by the action of the intersection of pressure waves. The safety and stability of the train have an impact. In this paper, a model of the middle carriage of a high speed train is established by multibody dynamics, and the moving load is simplified as a force and torque acting on the mass center of the train. By comparing the same running speed, the single vehicle and the constant speed line are rendezvous, the body swinging, the lateral force of the axle and the derailment system. The train safety performance indicators such as number, wheel load and load reduction rate indicate the impact of the pressure wave generated by the open line intersection on the safety of high-speed trains.
The finite element model of a high speed train head is established in this paper. The numerical model is used to strike a rigid wall with the initial velocity of v=10m/s and 20m/s (equivalent to the same train with the same train running speed of 72km/h and 144km/h). As the daily speed of this kind of train is below 200km/h, the impact speed has already been achieved. The coupler will absorb a part of the energy when the train is starting and braking, but the coupler absorbs less energy than the impact energy of the simulation system, and it falls off in a short time and has little effect on the collision resistance analysis. Therefore, the effect of the coupler in the impact event is ignored. The calculation event is 300ms. long. Through the crashworthiness analysis, the energy absorption time history curve of the original load bearing energy absorbing structure traction beam, the impact force of the rigid wall and the failure condition of the vehicle body are obtained.
Through numerical simulation, it is found that the original structure of the structural suction component traction beam is mainly Euler instability when the impact occurs, which is not conducive to the absorption of energy and the cushioning of the impact force. Therefore, combined with the experiment, four improved schemes are proposed for the local improvement of the original vehicle design and the fact that the vehicle body does not lengthen. In the main part, the original square tube structure is changed to the square tube with round angle, and the energy absorption tube with the same structure is added to the common axis position of the front end. Through numerical calculation, the energy absorption curve of the traction beam and the rigid wall reaction curve under the four schemes of two kinds of impact velocity are obtained, and the energy absorption performance of the four modified schemes and the main four schemes are compared. The results show that the best improved scheme can improve the energy absorption of the original design by 322% and the peak value of the counterforce by 12% at the speed of 10m/s, and the energy absorption increases by 288% at the speed of 20m/s and the peak value of the counterforce is reduced by 36%, and the effect is remarkable.
The dynamic response process of the middle carriage of a high speed train under the joint action of six kinds of constant speed (250 to 500km/h) clear line and the high speed low interference track spectrum of the German high-speed train is simulated by multibody dynamics. The body freedom (yaw, roll, head), lateral force of the axle, the derailment coefficient and the wheel load reduction rate with time are obtained. The result shows that the other safety indexes of the train meet the requirements except the wheel load reduction rate. The two indexes of the lateral force and derailment coefficient of the axle are all excellent, and the freedom of the body and the load reduction rate of the wheel weight. When the cross and shaking head of the body is much more than the speed above.400km/h, the wheel weight reduction rate is seriously overstandard. Compared with the safety standard for the wheel weight reduction rate index of the European and American countries, the standard of the dynamic wheel load reduction rate is too conservative in China, which can be appropriately relaxed and increased over the limit. The restriction of continuous action time should be taken into account in the safety evaluation of high-speed trains.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U270.34;U298

【参考文献】