【作者】 陈锐林；

【导师】 曾庆元；

【作者基本信息】 中南大学 ， 桥梁与隧道工程， 2008， 博士

【摘要】 强风中列车脱轨时有发生,轻则造成铁路运输中断,重则列车倾覆,造成车毁人亡的后果,社会影响极大。脱轨研究从来都是各国轨道交通领域的重大课题。国外对强风中列车的脱轨研究始于1879年12月28日的Tay铁路桥倒塌灾难,造成75人死亡,很多专家确信是当时正在桥上运行的列车脱轨后造成的桥毁人亡。2007年2月28日新疆列车在遭遇13级大风后发生脱轨、倾覆,造成了很大的社会影响。脱轨在我国铁路行车重大、大事故中的比例高达七成左右;随着我国高速客运专线建设的广泛展开,风对列车行车安全的影响越来越大,有时甚至处于支配性地位。保证列车安全运行更为重要。国内外学者对脱轨问题研究了一百多年,取得了很多很好的成果,然而尚有很多问题悬而未决。随着曾庆元院士列车脱轨能量随机分析理论的问世,很多问题迎刃而解。本文正是在列车脱轨能量随机分析理论的基础上考虑列车在风载荷作用下的脱轨分析,以期拓展该理论的应用范围,使其成为趋近于全天候的列车脱轨能量随机分析理论。此外,考虑到强风作用下列车脱轨往往伴随列车的倾覆,本文在对列车空气动力学进行详细分析计算的基础上,提出了一整套列车倾覆分析理论。本论文的主要研究如下:1.列车空气动力学方面要进行强风作用下列车脱轨分析,需要对列车空气动力学性能有全面的了解。因此本文对列车在横风作用下的绕流结构,受力特点,列车的风致振动进行了详细的理论分析、计算,并与试验结果进行了对比,证明了本文分析计算的正确性,其主要内容为:(1)通过对颤振进行详细的理论分析和计算,提出了由于列车断面较为钝化,其气动藕合作用应较弱,一般不会发生剧烈的经典颤振。又由于列车的颤振临界风速很高,故一般不用考虑颤振;(2)提出了作用在列车上的空气力,从数学上看,可看成是均值和脉动值之和;从空气动力学机理上来看是非常复杂的。对列车来说,主要包括:静风力,伴随卡门涡的释放而作用的脉动气动力和抖振部分;(3)将三维雷诺平均N-S方程(RANS)结合k-ε湍流模型,用有限体积法将控制方程离散求解。用SIMPLE法耦合压力-速度场。针对列车在不同风速下的气动力进行计算。模拟计算结果显示增大列车运行速度和横风速度,都会增大列车气动升力、气动阻力,并用呈加剧的趋势,均呈现出非线性现象。列车在高速、大横风情况下运行,以上两种非线性风险的影响将使得行车的安全性将受到极其严峻的挑战。(4)基于前沿追踪算法生成列车横断面绕流场的非结构动态网格划分,网格移动过程中,将网格看成实际结构,引入基于边的直系弹簧和基于顶点的扭转弹簧,从而对网格品质进行控制,防止崎变。采用非结构动态网格对计算流体域进行划分和移动,对流体控制方程做FVM构造,计算了列车横断面绕流。得出一些结论:列车横断面背风侧上下有很明显的脱离涡;列车迎风面是正压区,上、下表面和背风面均处于负压区中。当列车在倾覆过程中时,列车下表面处于正压区。(5)首次将抖振反应谱理论应用于列车的抖振分析中,计算出了车体和转向架的一阶升沉、横移和侧滚的抖振反应谱。2.强风作用下列车脱轨分析理论方面以列车脱轨能量随机分析理论为基础,通过对列车空气动力学性能的理论分析,计算,包括列车抖振反应谱的计算后,提出了一套风载荷下列车脱轨能量随机分析理论,从而使列车脱轨能量随机分析理论成为能判断无论有没有风都能适用的理论,第一次使列车脱轨能量随机分析理论能够适应列车脱轨计算的全天候应用,使列车脱轨能量随机分析理论趋于完善。同时创建了一整套列车倾覆分析理论。其主要内容包括:(1)对考虑风载荷的列车脱轨力学机理进行研究,提出了考虑风载荷的列车脱轨机理是列车-轨道(桥梁)时变系统(以下简称此系统)横向振动丧失稳定。(2)两种方法的提出,即提出了考虑风载荷的列车脱轨能量随机分析理论的时域法和频域法;(3)计算得到了各风速下的σ_p-v曲线,对原σ_p-v曲线进行了有益的扩充,使得列车脱轨能量随机分析理论成为趋近于全天候的理论;(4)建立了考虑风载荷的列车是否脱轨条件;(5)提出了考虑风载荷下列车是否脱轨第一、第二判别准则;(6)首次提出了列车倾覆条件和判据;(7)详细分析了列车倾覆过程绕流特性;(8)提出了加速倾覆的概念;(9)首次对遭遇13级大风的新疆列车脱轨与倾覆过程进行了分析,合理地解释了其脱轨的必然性和揭示了瞬间倾覆的原因;(10)对国内外多起强风中列车脱轨与倾覆进行了分析。计算结果均与实际情况一致,验证了本文提出的风载荷下列车脱轨能量随机分析理论与列车倾覆分析理论的正确性。更多还原

【Abstract】 Train derailment in strong wind happens frequently in the world, which wil bring big social impact. Train derailment wil lead to interupption of railway traffic, even result in catastrophe. Research of train derailment has been an important subjeet in railway transportation all over the world. The abroad started to research the theory of train derailment since collapse of Tay bridge, which happened in the evening of 28 December 1879. The Tay Bridge Disaster killed 75 persons. Many experts believe that train derailment results in collapse of Tay bridge. An train traveling through level 13 winter winds derailed and overturned in Xinjiang,China in 28 February 2007. which makes bad social impact in China. Train derailment have occupied 70% in all grave and serious accidents. With the widely-developed construction of the high speed railway line for passenger traffic, The influences of wind on the safety of train operation are becoming more and more important, even are top dog. The problem of train derailment has been studied for as long as more than one century and a great number of achievements have been made. However, many problems are up in the air yet. With Zeng’s analysis theory of random energy coming forth, many problems can be readily solved. In this dissertation,the analysis of train derailment in wind loads is studied based on analysis theory of random energy. Application range of Zeng’s theory can be opened up. One of contribution in this dissertation is making analysis theory of random energy become all weather theory. Further more, considering that goes with train overturn, a complete set of analysis theory of train overturn put forward. The main contents and contributions of the dissertation are as follows.1. On Train AerodynamicsIt is necessary demand that you have complete understand on train aerodynamic performances if you tend to analyse train derailment in strong wind. So characteristics of flow around train and aerodynamic forces on train and wind induced vibration of train are analysed and computed particularly in this dissertation. Theories and methods applied in this dissertation is proved to be validity after the consistency between numerical results and test results have been testified. The main contents and contributions on train aerodynamics of the dissertation are as follows.(1) Detailed academic analysis for train flutter has been done in the dissertation. Duing to non-streamline the transect of train, classical flutter will not take place. Flutter critical wind speed of train is very high, so flutter will not be considered in the dissertation.(2) It is considered that aerodynamic forces acted on train is composed of average and fluctuating part in the view point of math, but it is complicated for mechanism of aerodynamics. aerodynamic forces acted on train are mainly involved of static wind forces, fluctuating aerodynamic forces induced by Karmen eddies and buffet forces.(3) The three-dimensional Reynolds-averaged Navier-Stokes equations (RANS), combined with the k-E turbulence model,were solved using finite volume technique. The pressure-velocity fields were coupled using the SIMPLE algorithm. At each iteration the pressure correction was obtained by solving a velocity divergence-derived Poisson-like equation. With the computed aerodynamic forces, the formula of the limit speed which train passes curved rail in side wind ,was deduced in this paper, and applied to analyse the influences on aerodynamic forces to the limit speed. results of numerical investigations show aerodynamic lift and overtune moment increase more and more rapidly along with train speed and wind speed. The enhancement trends show nonlinear phenomena,enhance risk in the course of train movement. When train travels in high speed and encounters huge side wind, the influence involved by nonlinear risk increment extremly impair safety of train.(4) Unstructured dynamic meshes on fluid field around are generated based on frontal track algorithm. Meshes are looked as quasi-structure when Meshes are moving. Lineal spring attached to line and torsional spring attached to vertex are intrduced to prevent mesh quatity becoming bad. Fluid control equations are discretized by FVM technique. Numerical result for flow around the intsect of train has been gained. The following conclusions can be drawn. Obvious disppached eddies can be observed at upside and downside of leeward surface. Windward surface of train is in the place of positive pressure district. Top surface, bottom surface and leeward surface is in the place of negative pressure district. When train is in the process of overturn, bottom surface is in the place of positive pressure district.(5) For the first time, buffeting responses spectrum is applied to analyse buffeting responses of train. One order heave, lateral and roll buffeting responses spectrum for train body and bogie are computed in this dissertation.2. On analysis theory of train derailment in strong wind Based on analysis theory of random energy of train derailment, analysis theory of random energy of train derailment in wind is suggested in this dissertation after detailed academic analysis for train aerodynamics, including buffeting responses analysis was done. Thus, application range of analysis theory of random energy of train derailment is extended to all weather, i.e. common atmosphic wind field. One aim in this dissertation is for the purpose of enable origin theory further to tend to the consummation. After the first aim has been fulfilled, another aim, i.e. a whole set of analysis theory of train overturn is put forward,also. The main contents and contributions on train derailment and overturn theory of the dissertation are as follows.(1) The train derailment mechanism, which is the result of losing stability in lateral vibration status of train-track(bridge)time-varying system, is proposed in this dissertation.(2) Two kinds of methods are put forward, namely,time-domain method and frequency-method method for the theory of random energy of train derailment involved of wind loads are put forward.(3) With calculated results from former, curveσ_p-v is extended to in different wind speed,which make all-weather theory of random energy of train derailment.(4) Train derailment condition involved of wind is set up in this dissertation.(5) First and second discriminative rule of train derailment in wind is proposed in this dissertation.(6) Condition and discriminative rule of train overturn is put forward for the first time in this dissertation.(7) Characteristics of flow around train and aerodynamic forces on train in the process of train overturn is laboured.(8) The concept of train speedup overturn is put forward for the first time in this dissertation.(9) The process of Xinjiang train,which encountered level 13 winter winds, derailment and overturn is analysed. Derailment and overturn inevitability is explained in reason. The secret of train instant overturn is opened up for the first time in this dissertation.(10) Many cases of train derailment and overturn in strong wind, which occurs frequently in China and other countries of the world, are analysed in this dissertation. All the calculated results conform with the actual status, so the feasibility of the theory of energy random analysis involved of strong wind for train detailment and analysis theory of train overturn are verified.更多还原