高速铁路轨道动态质量管理方法

从线路几何尺寸异常突变和乘坐舒适度的要求更高等方面出发,分析高速铁路轨道动态质量管理面临的新问题;从检测数据对比、添乘检查确认和实时监控方面论述线路变化监控分析。针对高速铁路行车舒适度管理,提出建立高速铁路轮轨一体化轨道动态管理机制、加强轮轨关系不良分析和岔区轮轨不良分析措施;针对线路病害,提出加强线路几何尺寸不良与道床病害整治、道岔及线路钢轨修理措施,以期为我国高速铁路线路动态质量管理提供借鉴。     

几何参数对副构架径向转向架动力学性能影响的研究

比较了两种典型副构架径向转向架径向机构的不同点,通过分析副构架式径向转向架交叉杆水平面内的受力情况,建立转向架等效模型,解方程组得到其等效剪切刚度关于交叉杆横向安装跨距的函数表达式,分析出交叉杆几何参数对转向架动力学性能的影响,并通过SIMPACK仿真模型计算验证。     

柔性吊桥无应力初始状态的确定

为评估某柔性吊桥的承载力,笔者对其进行了空载状态几何形状测量和静载试验,并利用几何非线性有限元法对试验结果进行了数值模拟.着重探讨了利用结构现状参数,确定结构无应力初始状态的方法.有限元法的模拟结果与实测值的吻合证明了该方法的正确性.笔者建立的结构无应力初始状态确定方法,可用于大跨度索结构的有限元分析与设计.     

一种轮轨接触几何算法

提出并实现一种轮轨接触几何算法，可以检测铁道车辆系统动力学仿真在线计算时轮对与钢轨的刚性单接触斑、多接触斑和跳离情形．所得刚性接触斑可以为Hertz理论提供刚性穿透量和曲率，为非Hertz理论提供接触区域的法向间隙，为动力学仿真提供接触中心位置和法向方向．轮对与钢轨的计算机三维图形显示表明该算法是有效的．该算法已用于开发空间耦合的铁道车辆系统动力学仿真软件．     

Weather and road geometry impact on longitudinal driving behavior: Exploratory analysis using an empirically supported acceleration modeling framework

The objective of this paper is to quantify and characterize driver behavior under different roadway geometries and weather conditions. In order to explore how a driver perceives the rapidly changing driving surrounding (i.e. different weather conditions and road geometry configurations) and executes acceleration maneuvers accordingly, this paper extends a Prospect Theory based acceleration modeling framework. A driving simulator is utilized to conduct 76 driving experiments. Foggy weather, icy and wet roadway surfaces, horizontal and vertical curves, and different lane and shoulder widths are simulated while having participants driving behind a yellow cab at speeds/headways of their choice. After studying the driving trends observed in the different driving experiments, the extended Prospect Theory based acceleration model is calibrated using the produced trajectory data. The extended Prospect Theory based model parameters are able to reflect a change in risk-perception and acceleration maneuvering when receiving different parameterized exogenous information. The results indicate that drivers invest more attention and effort to deal with the roadway challenges compared to the effort to deal with the weather conditions. Moreover, the calibrated model is used to simulate a highway segment and observe the produced fundamental diagram. The preliminary results suggest that the model is capable of capturing driver behavior under different roadway and weather conditions leading to changes in capacity and traffic disruptions.     

冷天气起飞时的高度修正研究

对飞机在冷天气起飞时是否应该对高度进行修正问题进行了研究，通过理论分析和实际计算证明：由于冬季低温天气实际温度大大低于标准大气温度，几何高度可能比气压高度低几百英尺甚至更多。因此，冷天气起飞时应该对改平高度进行修正。文中给出了冷天气高度修正的通用计算方法，并以波音公司的图表为例介绍了冷天气高度修正方法。     

连续梁桥典型变形对轨道几何形位演变的影响

研究目的:连续梁桥变形引起的轨道几何形位演变直接影响线路运营速度和行车安全。轨道几何形位演变的有效防控是保证轨道平顺性的核心关键。以考虑两侧简支梁引桥及路基影响的3跨连续梁桥为研究对象,基于作者已建立的连续梁桥典型变形引起轨道几何形位改变的映射解析计算模型,定量化研究桥墩沉降,梁端横、竖向转角及梁体横、竖向错台等典型变形对CRTSⅡ型板式无砟轨道结构轨道几何形位改变的影响,并提出钢轨变形防控措施。研究结论:(1)钢轨变形量与连续梁桥变形幅值呈正比,具有明显"跟随性";(2)连续梁桥变形导致较大扣件力集中在梁缝处;(3)无论是桥墩沉降、梁端转角还是梁体错台,都会使在桥梁变形区域边界处的钢轨产生"上翘"的现象,且"上翘"值与桥梁变形幅值呈正相关,合理控制变形区域边界处的钢轨上翘,可保证线路高效安全运营;(4)本研究结论可为防治轨道几何形位演变提供理论依据。     

Sensitivity of the wheel–rail contact interactions and Dang Van Fatigue Index in the rail with respect to irregularities of the track geometry

This paper investigates the effects of the track geometry irregularities on the wheel–rail dynamic interactions and the rail fatigue initiation through the application of the Dang Van criterion, that supposes an elastic shakedown of the structure. The irregularities are modelled, using experimental data, as a stochastic field which is representative of the considered railway network. The tracks thus generated are introduced as the input of a railway dynamics software to characterise the stochastic contact patch and the parameters on which it depends: contact forces and wheelset–rail relative position. A variance-based global sensitivity analysis is performed on quantities of interest representative of the dynamic behaviour of the system, with respect to the stochastic geometry irregularities and for different curve radius classes and operating conditions. The estimation of the internal stresses and the fatigue index being more time-consuming than the dynamical simulations, the sensitivity analysis is performed through a metamodel, whose input parameters are the wheel–rail relative position and velocity. The coefficient of variation of the number of fatigue cycles, when the simulations are performed with random geometry irregularities, varies between 0.13 and 0.28. In a large radius curve, the most influent irregularity is the horizontal curvature, while, in a tight curve, the gauge becomes more important.     

六塔斜拉桥主梁制造阶段参数敏感性研究

为揭示大跨度多塔斜拉桥主梁制造参数对其结构力学行为的影响,并确定主梁关键敏感性参数对主梁成桥线形和拉索索力的影响情况。以嘉绍跨江大桥为研究对象,基于几何控制法的基本原理,建立考虑几何非线性效应的施工全过程有限元模型,根据主梁关键制造参数的误差统计结果,对比分析主梁制造参数变化对多塔斜拉桥力学行为的影响。结果表明:主梁自重和梁长参数变化时,对主梁成桥线形和拉索索力具有较大影响;主梁夹角参数变化时,对主梁成桥线形和拉索索力影响较小,但对主梁和索塔内力影响较大;在多塔斜拉桥中,当其中某塔主梁关键参数发生变化时,不仅对该塔的结构力学行为产生影响,而且对相邻各塔的结构力学行为均有一定程度的影响。     

两级增压涡轮几何参数对发动机性能的影响研究

基于涡轮通流模型,建立两级增压通流仿真平台,探讨了两级涡轮几何参数的改变对发动机性能的影响规律及原因,采用该平台对某车用两级增压柴油机进行仿真研究,并完成两级涡轮新的匹配设计.匹配结果表明,通过合理设计两级涡轮几何参数,可使该发动机低速扭矩提高7.4％,燃油消耗率降低6.9％.