【作者】 肖新标；

【导师】 金学松；

【作者基本信息】 西南交通大学 ， 载运工具运用工程， 2013， 博士

【摘要】 列车脱轨问题机理十分复杂,不确定的影响因素较多,是全世界铁路工业界难以解决的理论和技术问题。在车辆／轨道关键零部件失效和自然灾害等复杂环境状态下,高速列车运行安全性受到极大威胁,由其造成的重大脱轨事故并不少见。目前的车辆／轨道动力学理论方法难以描述复杂环境状态下高速列车动态行为、脱轨发生的瞬态过程、脱轨特征和机理。同时,全世界高速列车脱轨判别准则和安全评估准则不统一不完善、不科学,甚至不合理。现有的脱轨准则只考虑单一或少数影响因素,且被独立运用到列车安全评估中。因此,复杂环境状态下高速列车脱轨机理和安全运行评估研究有待进一步深入。论文受国家自然科学基金项目“复杂环境下高速列车动态脱轨机理的研究(50875218)”、“高速列车运行安全的关键科学技术问题研究(50821063)”和“四川省科技计划项目(2010JY0070)”等项目的资助,主要开展了以下几方面的研究工作：(1)建立了较为完整的高速列车动态脱轨机理研究模型,并发展了相应的数值程序。模型主要由五个子系统组成,分别是车辆系统动力学模型、轨道系统动力学模型、轮轨空间动态接触模型、车辆／轨道耦合界面激励模式和脱轨安全域评判新体系。对复杂环境状态,根据其特性,作为高速列车／轨道耦合动态系统的广义边界特性,体现在高速列车动态脱轨机理研究模型中。(2)改进了单节车和多节车车辆系统动力学模型。模型中,单节车辆由35个自由度的多刚体系统模拟；多节车辆考虑典型的8辆编组,每节车由42个自由度的多刚体系统模拟。忽略车辆系统所有部件的结构弹性变形,并假设车辆匀速运行,不考虑列车纵向的加、减速运动。车辆系统各连接部件简化为弹簧-阻尼连接单元,采用分段线性来模拟其非线性动力特性。(3)改进了三层(钢轨-轨枕-道床-路基)有砟轨道动力学模型和三维实体有限元板式无砟轨道动力学模型。轨下结构纵向被离散,离散原则以各轨枕支点为基元,考虑轨道刚度纵向不均匀变化特性。钢轨视为连续弹性离散点支承的无限Timoshenko梁,考虑钢轨的横向、垂向和扭转振动。有砟轨道中,轨枕简化为Euler梁模型,考虑轨枕的垂向弯曲振动和横向刚体运动,道床简化为垂向离散等效质量块。每个支撑单元采用双质量(轨枕和道床)三层(钢轨-轨枕-道床-路基)弹簧-阻尼振动模型。无砟轨道中,轨道板用三维实体有限元单元模拟,钢轨扣件和CA砂浆层用周期性离散的粘弹性单元模拟。(4)建立了轮轨空间动态耦合模型。模型中,轮轨接触点采用迹线法和最小距离法确定,考虑轨道系统动态响应和钢轨弹性变形对轮轨接触几何及轮轨耦合相互作用力的影响。轮轨法向力采用改进轮轨法向挤压量计算公式和Hertz非线性弹性接触理论求解。轮轨切向力采用Kalker线性理论计算,再以Shen-Hedrick-Elkins理论进行非线性修正。(5)提出和采用“跟踪窗户(Tracking Window)"新型车辆／轨道耦合激励模式。模型中,假设车辆匀速运动,忽略车辆／轨道系统纵向振动特性,车辆相对钢轨不移动,而轨下支撑结构,包括钢轨扣件、轨下垫层、轨道板、轨枕、道床及轮轨系统不平顺沿行车相反方向作相对运动,运动速度和行车速度相同。(6)补充完善了基于轮轨动态接触关系的轮轨接触点横向位置和车轮抬升量动态脱轨评判准则,提出和构建了脱轨安全域评判体系。其基本思想为,利用动力学模型计算各种关键因素对复杂环境状态下高速列车／轨道耦合系统动态响应的影响,结合几种常用的脱轨评价准则,确定不同评价准则下的脱轨安全界限,最终得到考虑多种影响因素及不同脱轨指标的列车脱轨与安全运行域,从而将其运用到高速列车的脱轨评价分析中。基于上述数值计算模型,针对复杂环境状态下高速列车脱轨问题,开展了轨道结构件失效、线路鼓胀、强风环境和地震环境等4方面的研究：(1)建立了轨道结构件失效下高速列车动态脱轨机理研究模型。计算分析了无砟曲线线路上,高轨、低轨和双侧扣件失效对车辆／轨道耦合系统动态响应和车辆脱轨安全性的影响,并对行车速度和扣件失效个数两个关键因素进行了脱轨安全性影响规律调查分析；计算分析了在有砟直线和有砟曲线线路上,轨下支撑失效对系统动态响应和车辆脱轨安全性的影响,对比分析了轨下支撑失效下脱轨临界工况和脱轨发生工况的车辆脱轨行为,调查分析了行车速度和扣件失效个数两个关键因素的影响规律,构建和分析了轨下支撑失效下高速列车的脱轨与安全运行域。(2)建立了鼓胀状态下高速列车动态脱轨机理研究模型。计算分析了直线有砟和曲线有砟两种轨道类型,线路鼓胀对车辆／轨道耦合系统动态响应和车辆脱轨安全性的影响,对比分析了线路鼓胀状态下脱轨临界工况和脱轨发生工况的车辆脱轨行为,调查分析了鼓胀幅值、波长和行车速度等关键因素的影响规律,构建和分析了线路鼓胀下高速列车的脱轨与安全运行域。(3)建立了强风状态下高速列车动态脱轨机理研究模型。计算分析了直线稳态横风、瞬态阵风和隧道出口瞬态阵风等典型强风环境下车辆／轨道耦合系统动态响应和车辆脱轨安全性,对比分析了强风环境下脱轨临界工况和脱轨发生工况的车辆脱轨行为,调查分析了风速、风向角和行车速度等关键因素的影响规律,构建和分析了强风环境下高速列车的脱轨与安全运行域。(4)建立了地震状态下高速列车动态脱轨机理研究模型。计算分析了横向、垂向和横-垂向地震波作用下车辆／轨道耦合系统动态响应和车辆脱轨安全性；对比分析了地震环境下脱轨临界工况和脱轨发生工况的车辆脱轨行为；调查分析了地震波频谱特性、地震波强度、横-垂向地震波比值和行车速度等关键因素的影响规律；构建和分析了地震环境下高速列车的脱轨与安全运行域。更多还原

【Abstract】 The mechanism of train derailment is quite complicated and involved in many uncertain influencing factors. Fully understanding and solving it is still a very difficult theoretical and technological project in railways all over the world. Now the environmental state of natural disasters and the failure of the key parts of railway vehicle and track is a threatening to the safety operation of high-speed trains, and in the past caused many serious derailment occurring. So far, the dynamical behavior and characteristics of high-speed operating trains in such a severe environmental state cannot be clearly described by using the existing coupling dynamics theories of railway vehicle and track, especially the transient process of derailing and its mechanism understanding. In addition, railways around the world have not reached a consensus on the widely used derailment criteria and operation safety estimating standards of high-speed trains. The railways of different countries and areas hire the different derailment criteria and operation safety estimating standards, some of which are deficient, unscientific and even unreasonable. People don’t understand their internal relations even if the application purposes of them are the same. The most of them consider a single influencing factor or few influencing factors only. Usually one or two of them is alonely used in evaluating the safety operation of high-speed trains and the obtained consequences have been doubted. Hence, it is very necessary to further make an investigation into the derailment mechanism of high-speed trains operating in the severe environmental state, the boundaries between derailment occurring and safety operation areas, and the internal relation and difference of the existing derailment criteria.The thesis is funded by the National Natural Science Foundation Projects of China’Study on Mechanism of High-speed Train Transient Derailment in Severe Environmental State (50875218)’and’Research on Key Problems of Science and Technology of High-speed Trains in Satety Operation (50821063)’, and’Science and Technology Planning Project in Sichuan Province (2010JY0070)’. The following researches were conducted.(1) A whole model of the transient derailment mechanism of high-speed train and its matching computational code are developed. This model considers the five subsystems:a railway vehicle, a track, wheel/rail in transient rolling contact, the boundary excitations of the vehicle/track coupling system and a new system of estimating safety operation of high-speed trains. According to the characteristics of the defined severe environmental state, they are included in the dynamics model of a high-speed train coupled with a track as general boundary conditions.(2) The developed model of railway vehicle considers both single vehicle and multi-vehicles. The single vehicle model has35degrees of freedom and the multi-vehicle model considers8vehicles with42degrees of freedom for each vehicle, which are the rigid multi-body models. All the parts of the vehicle in service neglect their deformation, the operation speed is assumed to be a constant and the accelerations and decelerations of the vehicle parts are also ignored in the modeling. The connections between the parts are replaced with the equivalent spring/damper systems. The nonlinear connections are characterized with piecewise linearities.(3) This thesis improves the ballasted track dynamics model with three layers (rails-sleepers-ballast) and the slab track dynamics model which uses the finite element method to model the slabs. The infrastructure of the rails is treated as a discrete system with sleeper supporter units, in which the variation of the track stiffness along the track is considered. A pair of rails is modelled by using the finite Timoshenko beam with discrete supporters which takes the vertical and lateral motions and rotation of the rail into account. In modeling the ballasted track, a sleeper is treated as the Euler beam the vertical and lateral motions and rolling of which are considered. The ballast bed is replaced with equivalent discrete mass bodies. Each support unit of the track consists of dual-mass (sleeper and ballasted body) and three-layer spring-damper system (rail-sleeper-ballast bed-roadbase). In modelling the slab track, the slab is modeled by using three-dimensional solid finite elements, the fasteners and the CA screed are replaced with periodically discrete viscoelasticity unit systems.(4) A new spatial calculation model of wheel/rail in transient rolling contact is developed, in which the wheel/rail contact points are still determined based on the traditional "tracing method" and the traditional "minimum distance method ". The model considers the effect of the track transient responses on the wheel/rail contact geometry and the interaction of the wheel/rail. The normal forces are calculated by using the improved formula of wheel/rail normal approaching and the nonlinear spring based on Hertzian contact theory. The wheel/rail tangent forces are determined by using the model of Shen-Hedrick-Elkins.(5) In the modelling a train operating along a track a "Tracking Window" technique is adopted to simulate the train moving with respect to the track (tangent and curved tracks) at a constant speed. This is a new vehicle/track interaction model. In this model, the constant speed of the train is available and it is assumed that the infrastructure of the rails moves at a constant speed of the train with respect to the train that is assumed to be in a static state in the window. The longitudinal motion variation of all the parts of the vehicle and the track is neglected. The infrastructure contains fasteners, slabs or sleepers, ballast, CA layer replacement, subgrade and irregularity between wheel/rail.(6) In estimating the dynamical behaviour and the safety operation of a high-speed train, two more derailment criteria are put forward based on the lateral location of wheel/rail contact point and the wheel rise with respect to the rail, which are obtained through the calculation by using the improved model of wheel/rail in transient rolling contact. A new evaluation system for estimating the safety operation and the derailment occurring of high-speed trains in severe environmental state is developed. The basic idea of the estimating system is that the effect of the key influencing factors in changing on the dynamical behavior and derailment occurring process of a high-speed train operating in several severe environmental state is numerically reproduced by using the transient derailment model of a high-speed train with a track, in which the safety operation area, the derailment occurring area and their boundaries are obtained through the detailed numerical calculation. These areas are constructed by using the key influencing factors and the limits of all the considered derailment criteria in the present paper and their internal relationships are shown clearly in these areas. They are very useful for estimating the safety operation of high-speed trains.Using the above models and methods analyze the dynamical behavior and derailment occurring process of a high-speed train operating in several severe environmental states which includes fastener failure, track buckling, strong crosswind and earthquake.(1) The transient derailment model of high-speed vehicle operation under the condition of fastener failure is developed, and used to analyze the effect of the failure of fasteners on the dynamical behaviour, the safety operation and the derailment occurring of a high-speed vehicle. The analysis considers the cases that the failure of different fasteners occurs, respectively, on the high rail, the low rail and both the high and low rails of the tangent and curved ballasted tracks. In the analysis, the two key influencing factors are, respectively, the number of the failed fasteners and the operation speed of the vehicle, which are used to construct the safety operation and derailment occurring areas and their boundary of the vehicle, and also the limits of all the considered derailment criteria shown in the areas.(2) The transient derailment model of high-speed vehicle operation under the condition of track buckling is developed, and used to analyze the effect of the track buckling on the dynamical behaviour, the safety operation and the derailment occurring of a high-speed vehicle. The analysis considers the2cases that the buckling occurs, respectively, on a tangent and curved ballasted tracks. In the analysis, the three key influencing factors are, respectively, the wavelength and amplitude of the track buckling and the operation speed of the vehicle, which are used to construct the safety operation and derailment occurring areas and their boundary of the vehicle, and also the limits of all the considered derailment criteria shown in the areas.(3) The transient derailment model of high-speed vehicle operation under the condition of strong crosswind is developed, and used to analyze the effect of strong crosswind on the dynamical behaviour, the safety operation and the derailment occurring of a high-speed vehicle operating on a tangent track. In the analysis, the three key influencing factors are, respectively, the wind speed, the wind angle and the operation speed of the vehicle, which are used to construct the safety operation and derailment occurring areas and their boundary of the vehicle, and also the limits of all the considered derailment criteria shown in the areas.(4) The transient derailment model of high-speed vehicle operation under earthquake is developed, and used to analyze the effect of earthquakes on the dynamical behaviour, the safety operation and the derailment occurring of a high-speed vehicle operating on a tangent track. In the analysis, the four key influencing factors are, respectively, the earthquake intensity, the direction of earthquake wave propagation, the vehicle speed, and earthquake spectrum characteristics. The former three factors are used to construct the safety operation and derailment occurring areas and their boundary of the vehicle, and also the limits of all the considered derailment criteria shown in the areas.更多还原