Longitudinal train dynamics of electric multiple units under rescue

Once operating trains are disabled on the railway lines,an efficient manner is to utilize the train for train rescue.Owning to the different train and coupler types,it is difficult to formulate uniform regulations for train to train rescue.In this paper,the longitudinal train dynamics of electric multiple units under rescue were analyzed by field and laboratory tests.The angling behavior of the brakinginduced coupler under compressed in-train forces was analyzed.A dynamic model for the train and draft gear system was developed considering accurate boundary limitations and braking characteristics.The safety indices and their limits for the coupled rescue train were defined.Thedynamic evaluations of different train to train rescue scenarios were analyzed.It is indicated that the coupler vertical rotation occurs during the emergency braking applied by the assisting train.The vertical force components of intrain forces lead to the carbody pitch behavior and even cause local destructions to the coupler system.The carbody pitch motion can arise the inference of in-train devices.Based on the safety evaluation of train and coupler system,the regulations for typical train to train rescue scenarios were formulated.

EMU6动车组气动声学性能分析

采用三维、不可压缩和Lilly LES+FW-H方法,对1:8缩比3车编组EMU6动车组以200,250,300和350 km/h的车速运行时进行气动噪声特性数值模拟,得到列车不同速度级运行时的压力、速度与涡量分布,表面脉动压力、辐射声场等气动与声学性能。研究结果表明:偶极子声源强度主要分布在转向架及其周围的车体表面位置;A计权声压频谱在略小于1 000 Hz频率处测点声压级达到峰值;气动噪声分布频带很宽,噪声能量在1 000 Hz左右较为集中,往高频和低频部分则逐渐衰减;头车流线型附近声压级较大,在尾车以后越远离车体,声压级越小。其研究结果可为高速动车组的气动声学特性优化研究提供参考依据。

Application and development of friction stir welding technology in high speed EMU manufacturing

The application status of friction stir welding technology is introduced,and the application research of advanced FSW technology in the manufacture of high-speed electric multiple unit aluminum alloy body is analyzed,including the application of traditional friction stir welding technology to a combination of a lap joint and butt joint,and butt joint of large thick plate by both sides process,also introduces bobbin-tool friction stir welding to a butt joint and three-dimensional space curved friction stir welding to T-joint. At the same time the future development trend of new FSW technology derived from traditional FSW technology in rail vehicle manufacturing industry is put forward. As the fast developing of critical technology used on railway vehicles,quick applying advanced welding technology will affect products quality,manufacturing cost and production cycle time directly,and it certainly will be one of the approaches to develop markets by all the railway vehicles manufacturing enterprises.

Analysis of torque transmitting behavior and wheel slip prevention control during regenerative braking for high speed EMU trains

The wheel-rail adhesion control for regenerative braking systems of high speed electric multiple unit trains is crucial to maintaining the stability,improving the adhesion utilization,and achieving deep energy recovery.There remain technical challenges mainly because of the nonlinear,uncertain,and varying features of wheel-rail contact conditions.This research analyzes the torque transmitting behavior during regenerative braking,and proposes a novel methodology to detect the wheel-rail adhesion stability.Then,applications to the wheel slip prevention during braking are investigated,and the optimal slip ratio control scheme is proposed,which is based on a novel optimal reference generation of the slip ratio and a robust sliding mode control.The proposed methodology achieves the optimal braking performancewithoutthewheel-railcontactinformation.Numerical simulation results for uncertain slippery rails verify the effectiveness of the proposed methodology.

Investigations on lubrication characteristics of high-speed electric multiple unit gearbox by oil volume adjusting device

In this paper,a numerical simulation model of the flow field in a gearbox with an oil volume adjusting device is established for the first time to study its influence on the lubrication characteristics of a high-speed electric multiple unit(EMU)gearbox.The moving particle semi-implicit(MPS)method is used to numerically simulate the internal flow field of the gearbox of the high-speed EMU under working conditions.The effects of the velocity of the high-speed EMU,the immersion depth,and the oil sump temperature on the power loss of the gears and the lubricant quantity of each bearing are studied and provide an effective tool for the quantitative evaluation of the lubrication characteristics of the gearbox.The lubrication characteristics of the gearbox under different working conditions are studied when the oil volume adjusting device is closed and opened.The results show that the oil volume adjusting device mainly changes the amount of lubricant stirred by the output gear by changing the flow rate of lubricant from the cavity pinion(Cavity P)to the cavity gear(Cavity G),and thus affects the power loss of gears and the lubricant quantity of each bearing.

High-Speed EMU TCMS Design and LCC Technology Research

This paper introduces the high-speed electrical multiple unit （EMO） life cycle, including the design, manufacturing, testing, and maintenance stages. It also presents the train control and monitoring system （TCMS） software development platform, the TCMS testing and verification bench, the EMU driving simulation platform, and the EMU remote data transmittal and maintenance platform. All these platforms and benches combined together make up the EMU life cycle cost （LCC） system. Each platform facilitates EMU LCC management and is an important part of the system.

Preventive condition-based maintenance model of EMU components based on stochastic differential equation

To improve the operation and maintenance management level of large repairable components,such as electrical equipment,large nuclear power facilities,and high-speed electric multiple unit(EMU),and increase economic benefits,preventive maintenance has been widely used in industrial enterprises in recent years.Focusing on the problems of high maintenance costs and considerable failure hazards of EMU components in operation,we establish a state preventive maintenance model based on a stochastic differential equation.Firstly,a state degradation model of the repairable components is established in consideration of the degradation of the components and external random interference.Secondly,based on topology and martingale theory,the state degradation model is analyzed,and its simplex,stopping time,and martingale properties are proven.Finally,the monitoring data of the EMU components are taken as an example,analyzed and simulated to verify the effectiveness of the model.

车端侧滚减振装置对高速双层动车组动力学性能的影响分析

双层动车组设置较大的二系横向阻尼来抑制一次蛇行引起的共振,而较大的二系横向阻尼会使车辆的横向平稳性变差。针对某型高速双层动车组横向平稳性差的问题,基于车端侧滚减振装置的工作原理建立了车端侧滚减振装置在车体滚摆和摇头运动状态下的数学模型,并将AMEsim软件中建立的减振器仿真模型与台架试验进行验证。最后通过建立车端侧滚减振装置与被试车辆的联合仿真模型,在不改变车辆现有悬挂参数的基础上对车端侧滚减振装置的关键参数进行优化选取。仿真结果表明,车端侧滚减振装置可以在不影响车辆垂向平稳性、保证曲线运行安全性的前提下有效改善双层动车组的横向平稳性。

考虑个体差异的车轮二元相关退化可靠性分析

由于动车组车轮受加工装配及工况载荷等不确定因素的影响,车轮退化过程复杂,存在显著的个体差异及多个性能退化特征量,且多个退化特征量间相互耦合,仅考虑单个性能特征量难以全面反映其退化过程。因此,以轮缘和轮径作为车轮退化特征量,通过随机化尺度参数表征车轮个体差异,采用Gamma过程和Copula函数建立二元相关退化模型,并根据赤池信息准则(Akaike Information Criterion, AIC)筛选Copula函数,得到可靠度解析式。基于某型动车组车轮实测磨耗数据,对车轮进行可靠性分析,同时通过车辆动力学模型进行仿真验证。结果显示:考虑二元相关时的可靠性结果比仅考虑一元退化更贴近车辆实际运行情况;根据动力学仿真结果体现了考虑个体差异的必要性,表明所提模型能够更准确地表征车轮退化过程,可为可靠性分析以及维修决策优化提供理论支撑。

动车组合闸过电压故障机理兮析及仿真研究

[目的]动车组出分相时,断路器合闸产生的过电压会加剧高压设备的绝缘老化,研究合闸过电压的产生机理及影响因素对动车组主电路绝缘匹配和设备选型具有理论意义。[方法]结合动车组主电路结构和过分相过程,分析其正常运行方式下操作过电压的形成原因。考虑真空断路器合闸弹跳特性对过电压的特殊影响,建立动车组主电路仿真模型;对比研究动车组主电路合闸过电压特征,得出主回路状态动作时刻、动车组高压电缆参数、接触网参数及设备特性对过电压的影响规律。[结果及结论]极端状态下过电压峰值为工频电压峰值的2.39倍,接近《高速动车组整车试验规范》规定的2.4倍,在极端工况下产生的过电压会对动车组高压设备的绝缘性能产生影响,甚至导致击穿现象。因此,需采取如采用相控合闸技术控制断路器在目标相位闭合、选择单位分布电容较小的高压电缆、改进真空断路器的机械特性等相关措施进行防范,以有效降低动车组合闸过电压。

基于混合维修机制的动车组多设备系统维修策略优化

为降低动车组多设备系统一个寿命周期内的维修总成本,以动车组某设备系统为研究对象,采用混合式故障率演化规则描述其故障率变化,以预防性维修成本和故障维修成本为主要成本考量,对其一个寿命周期内的维修经济性进行优化研究,并结合我国动车组维修实际,分别建立等周期预防性维修策略和基于可靠性的预防性维修策略模型。通过分析动车组系统中各单设备在两种维修策略下的维修总成本,选择使维修总成本最低的维修策略作为该设备一个寿命周期内的最终维修策略,进而提出一种动车组多设备系统混合维修策略。算例结果表明,混合维修策略下动车组多设备系统的维修总成本相较于等周期预防性维修策略降低了19.3%,相较于基于可靠性的预防性维修策略降低了16.7%。

考虑运行图抽线调整的城际铁路动车周转计划编制

针对现有城际铁路动车组周转计划编制方法未考虑运行线客座率分布,导致抽线调整时难以单独停运低客座率车次而不影响高客座率车次的问题,本文提出一种适用于运行图抽线调整的动车组周转计划优化编制方法。以最小化动车组使用数量及交路中运行线客座率差异为目标,考虑满足一级修等约束条件,构建非线性整数规划模型;通过线性化处理并结合Hierholzer's算法筛选合格解的方式,高效求解模型。案例分析表明:相较于只考虑动车组使用数量的传统方法,该模型在不增加动车组使用数量的情况下,可以显著降低各交路中运行线客座率的差异。优化后的交路中运行线客座率极差提高了68.67%,交路中运行线客座率方差之和降低至对比方案的66.27%。抽线调整时,采用优化方案能够更精确地优先取消低客座率运行线,有效保留高客座率运行线。在抽线条数分别设定为1,2,3的情况下,优化方案停开的运行线中,客座率低于60%的运行线的占比均保持在77%以上,而对比方案中该比例均未超过45%;优化方案中被取消车次的平均客座率比对比方案分别降低了4.48%、5.88%和6.01%。

动车组充电机直流支撑电容寿命评估方法研究

充电机是动车组直流供电系统的核心环节,而直流支撑电容是充电机中的关键元件,如何准确评估直流支撑电容的寿命状态对充电机的故障预测及修程修制的合理安排具有十分重要的意义。针对此问题,对动车组充电机直流支撑电容失效机理进行分析,研究不同失效模式对电容退化程度的影响及对应的失效判据;在此基础上,提出一种基于阿伦尼斯模型的电容双应力加速寿命模型;为验证所提模型的正确性,开展基于不同纹波电流和温度的加速寿命实验,通过加速寿命实验确定电容实际失效时间,其与电容双应力寿命模型计算所得的电容理论失效时间相比,误差小于8.7%,验证了所提电容双应力加速寿命模型的正确性。在此基础上,进一步提出动车组充电机直流支撑电容寿命评估方法,实现动车组充电机直流支撑电容在实际运营工况下寿命的准确评估。

基于Wiener退化过程的动车组部件状态-机会维修模型分析与研究

针对动车组多部件存在运行维修成本高、欠维修或过维修的现象以及故障影响范围大等问题,提出一种基于Wiener退化过程的部件状态-机会维修优化模型。该模型利用Wiener过程描述部件在运行过程中的劣化程度,通过基于指数分布的随机几何过程反映不完全维修后部件的劣化损伤,同时利用定期检测获取部件的实际劣化值。从随机过程和拓扑的角度,分析不同类型维修策略之间的区别与联系。结合单部件状态维修优化策略,求得各部件的最优状态阈值和维修检测周期。引入机会阈值与状态阈值的比值,结合部件退化过程与状态阈值、机会阈值之间的关系,推导部件状态、机会维修次数期望值的数学表达式,建立状态-机会维修策略模型,采用蒙特卡洛算法进行模拟,确定各部件的最佳机会阈值,达到优化维修费用率的目标。以某型号动车组牵引供电系统为例,通过仿真验证,表明采取状态-机会维修模型,可以有效减少停机次数,降低维修费用率。

服役环境下动车车底装备滑槽疲劳载荷谱的编制与验证

随着动车组向更高速度发展,对列车轻量化的需求愈发迫切。在现有的动车组平台中,将没有横梁底架的车体改为底架滑槽吊挂能够显著减轻设备框架的质量和体积,实现列车轻量化目的。然而,滑槽吊挂引起的最为关切的问题是结构的疲劳强度能否满足需求。为了了解结构的疲劳强度性能,基于服役中动车组车下设备振动加速度,结合现有标准体系,采用服役全周期内工况组合和载荷外推方法,采用累积损伤原理和疲劳试验加速法,编制107次循环次数下的等效振动幅值,并开展滑槽结构疲劳强度试验。研究结果表明:与既有标准体系相比,考虑服役环境的车下设备垂向载荷小于标准值,横向和纵向载荷大于标准值;当轻量化高速动车组大质量车下设备采用滑槽吊挂方式时,结构可以满足30年设计寿命要求。

高速动车组用滚动轴承失效模式及对策展望

全面介绍了各主型高速动车组用轴箱轴承、齿轮箱轴承、牵引电动机轴承以及各类风机用轴承的型号、结构以及相应的车载和地面安全保证措施,汇总了轴承运行过程以及检修过程中的典型故障和主要失效模式,分析了轴承故障的产生原因,建议从车辆系统匹配设计角度确定旋转系统中轴承的边界载荷、顶层技术要求,优化轴承钢冶炼、热处理、机加工和组装等轴承制造工艺,以保证轴承产品质量一致性,进而避免轴承早期失效,为动车组安全运营,各系统旋转部件修程修制的制定和动车组用滚动轴承国产化提供借鉴和帮助。

动车组头车声固耦合模态分析及多目标优化

目前针对高速列车领域声固耦合共振现象的产生机理和影响因素尚缺乏深入探讨,并且基于声固耦合共振理论的车体优化设计也需进一步开展。该研究基于模态等效和质量等效原则建立动车组头车有限元模型,分别进行结构模态、声场模态和考虑内外声场影响的声固耦合模态分析。分析结果表明:结构模态频率符合头车设计规范;声场模态存在与结构模态相近的特征频率,为后续耦合共振优化提供依据;内外声场的耦合作用导致结构和声场系统的模态参数变化,论证了模态分析中考虑声固耦合因素的必要性。基于模态分析结果,对动车组头车结构进行了两项优化设计:以车体质量最小化为目标,车身厚度为设计变量,在满足一阶垂弯模态频率约束条件下进行车体减重设计;为避免耦合共振影响,提取结构和声场固有频率值接近的模态阶次,将二者的频率差最大化作为优化目标,引入车体减重设计模型,形成头车轻量化与舒适性指标同步提升的多目标优化体系。

温度和光照对动车组用矿物型变压器油荧光特性的影响

牵引变压器渗漏油检测是动车组运行故障检测的重要部分。动车组运行故障图像检测系统采集的近红外底板图像中渗漏变压器油痕迹与水迹的特征相似,致使列检员与图像识别算法均无法有效识别渗漏油痕迹,进而导致渗漏油故障的误报率高,影响列车的正常运行和检修效率。由于水不具有荧光特性,而矿物型变压器油具有紫外荧光特性,故可通过荧光成像将两者区分。另外,由于动车组运行季节、地域、时间段不同,致使渗漏的变压器油处于不同的环境条件中,进而影响渗漏油的荧光特性。而渗漏油的荧光特性决定荧光成像系统激发光源波长和成像波段的选取。因此,为了明确动车组用矿物型变压器油的荧光特性,以及两个主要环境因素温度、光照对荧光特性的影响,首先制备了不同温度、不同光照条件下的变压器油样本;而后,利用荧光光谱仪采集样本的三维荧光光谱,进而分析样本的荧光特性、温度和光照对荧光特征峰位置和强度的影响。结果表明,动车组用矿物型变压器油具有两个较强的荧光激发/发射峰,分别位于350/382 nm和350/402 nm;温度的升高引起荧光强度下降,但未改变荧光波峰位置;光照强度的增加与光照时间的延长都引起荧光强度下降,但未显著改变荧光波峰的位置;在动车组运行监测时间间隔内,温度和光照未显著改变油品的荧光特性。实验结果为荧光成像检测动车组用矿物型变压器油的渗漏故障提供了实验依据和数据支持。

高速动车组空气弹簧内部流场分析及其对动力学特性的影响

空气弹簧作为高速动车组二系悬挂中的重要元件,直接影响了车辆的运行品质,如何建立更加贴近实际的空气弹簧模型逐渐成为车辆动力学分析的重点。基于流体力学理论对空气弹簧内部气体方程进行了推导,依据动网格理论建立了空气弹簧流体力学模型,并通过台架试验验证了模型的准确性。探索了空气弹簧系统内部湍流的计算方法,研究了空气弹簧不同载荷下的刚度特性,进一步分析了空气弹簧的动态特性。研究空气弹簧系统结构参数对垂向特性的影响,通过对管路不同结构参数下Helmholtz共振频率的计算,得出当空气弹簧激振频率与Helmholtz共振频率相同时,会增大空气弹簧阻尼系数。不同连接管路直径下,频率在1.0~5.0 Hz内,随着频率的增大,动刚度明显增大,当频率大于5.0 Hz之后,动刚度逐渐减小并趋于水平;频率在0.5~5.0 Hz内,连接管路直径越小,阻尼系数越大且具有一定滞后性,当频率大于10.0 Hz之后,阻尼系数趋近于0。不同连接管路长度下,频率在1.0~7.0 Hz内,频率越大动刚度越大,当频率大于7.0 Hz之后,随着频率的增加,动刚度逐渐减小并趋于稳定;频率在1.0~9.0 Hz内,连接管路长度越短,空气弹簧阻尼系数越小。