Energy-saving operation approaches for urban rail transit systems

With the accelerated urbanization in China, passenger demand has dramatically increased in large cities, and traffic congestion has become serious in recent years. Developing public urban rail transit systems is an indispensable approach to overcome these problems. However, the high energy consumption of daily operations is an emerging issue due to increased rail transit networks and passenger demands. Thus, reducing the energy consumption and operational cost by using advanced optimization methodologies is an urgent task for operation managers. This work systematically introduces energy-saving approaches for urban rail transit systems in three aspects, namely, train speed profile optimization, utilization of regenerative energy, and integrated optimization of train timetable and speed profile. Future research directions in this field are also proposed to meet increasing passenger demands and network-based urban rail transit systems.     

Coupling analysis method for a large-scale structure exposed to synchronous hoisting loads

Large-scale synchronous hoisting equipment is widely used in the construction field. A coupling analysis method for global and local structures exposed to synchronous hoisting loads under working conditions is presented. An integrated analysis flow based on virtual prototyping is provided for the coupling analysis process with different design and simulation software tools, which includes project design, CAD and CAE model-building and interchange, data coupling and analysis. The theoretical basis of finite element analysis for synchronous hoisting loads is deduced. A practical case of the coupling analysis for a large-scale structure exposed to synchronous hoisting loads is studied and validated. The coupling analysis method can well improve the analysis level and efficiency to predict the mechanical effects in an operating situation.     

论城市轨道交通的衔接与发展

我国城市公共交通领域已经进入了一个快速发展的建设时期,以北京城市轨道交通规划为例,分析当前我国城市轨道交通在规划、建设及运营方面存在的问题,借鉴国际大都市轨道交通在规划、建设、运营方面的轨道交通方式、客流出行换乘方便、整合既有各种资源、交通带动城市发展的经验,提出了应建立综合协调机制、完善轨道交通规划、打造综合交通枢纽的优化原则,以及利用国有铁路资源实现轨道交通换乘与衔接具体建议。     

Enhancing resilience assessment and bus bridging service design for large-scale rail transit systems under disruptions

This paper proposes a more computationally efficient approach for resilience assessment of rail transit system under disruptions. An improved linear programming model is developed to depict commuter flows and estimate system statuses. To address the computational challenge caused by the complexity of system, a four-step approach is proposed based on the proposed commuter flow model. In the first step, Origin-Destination (OD) pairs are divided into smaller groups and their flows under normal conditions are estimated by the proposed model separately, with the assumption that the railway capacity is sufficient relative to demand. Next, overall system statuses under normal conditions, including commuters on each train and spare capacities of each train are calculated by integrating results obtained in the first step. In the third step, system statuses under disruptions are estimated. In this step, we assume that unaffected commuters will not change their routes and flows of all affected commuters are estimated by a modified commuter model with given spare space of trains. Based on these outputs, several critical measures are introduced and calculated to quantify the resilience, resistance, and recovery ability of rail network systematically. We also demonstrate how our approach could be used to facilitate design and evaluation of bus bridging service. The proposed approach is demonstrated on the core part of Hangzhou rail transit network.     

复合QRD型轨道交通声屏障的设计及性能分析

低频噪声绕射问题是目前声屏障设计亟需解决的难题,随着数论扩散体的应用,出现了在声屏障上使用二次余数扩散体（Quadratic Residue Diffusers,QRD）的尝试。但是,由于环境的影响,其工程适用性并不强。以声学传播特性为基础,结合数论扩散体原理并考虑材料使用量提出了一种新型声屏障。用Lms.virtrual.lab软件,采用自动匹配层（Automatic Matched Layer,AML）有限元方法并考虑声振耦合,验证了其应用于轨道交通时优于扩散体复合T型声屏障及传统倒L声屏障的降噪性能,尤其在低频段降噪效果明显,有较高的工程适用性和现实意义。     

宁波轨道交通1号线声屏障设计中的若干问题研究

在国内的同期城市轨道交通声屏障建设工程中,宁波轨道交通1号线规模最大、投资最多,特别是大量应用了全封闭的声屏障措施,由此带来的诸多问题需要在设计过程中研究解决。结合工程特点,提出了声屏障设计的任务、原则和重点,并进行了若干专题研究。景观造型专题中,采取了多项景观设计措施,并对三种桥面布置方案作了对比分析;根据性能特点,选择了适当的声屏障材料;在全封闭声屏障性能研究中,分别对内部热环境、排烟和声学效果进行了分析,并给出了综合的解决方案。最后介绍了1号线的声屏障设计方案。声屏障实施后的测试结果达到设计预期降噪量,满足环保要求。该工程对国内城市轨道交通声屏障设计具有示范作用。     

高架轨道桥梁新型橡胶减振支座的减振效果分析

为减小列车在高架轨道桥梁上运行引起的环境振动,开发了一种新型橡胶减振支座。此新型支座采用高阻尼厚层橡胶块倾斜布置的设计方案,在实现竖向减振的同时还可以提供较大的横向水平刚度;为研究这种新型支座的减振效果,建立了上部质量块-橡胶减振支座-桥墩体系有限元模型,采用竖向扫频激振的方式对其减振效果进行数值模拟;设计了一系列工况对影响新型支座减振效果的因素进行分析。研究表明:激振力幅值对新型支座的振动插入损失无影响,但增大桥墩高度会导致新型支座的振动插入损失减小;当激振力幅值取140 kN、桥墩高度取6 m时,新型支座的振动插入损失为17.53 dB;在满足承载力的情况下,增大橡胶块的倾角、增大橡胶块中橡胶层总厚度、减少橡胶层数的划分,可以降低新型支座的压缩刚度,进而提高新型支座的减振效果。     

现代轨道交通刹车材料的发展与应用

分析了轨道交通车辆用盘形制动装置中闸片/制动盘组成的摩擦副的工作条件及其对材料的要求,介绍了铸铁闸片、树脂基闸片、铁基和铜基粉末冶金闸片的性能特点及适用领域,重点分析了粉末冶金闸片各组元的功能及摩擦磨损性能调控机制.基于制动盘热斑形成机理,阐明了闸片形状与排布对制动盘热源分布的影响规律.阐述了铸铁、铸钢、锻钢、金属基复合材料和C/C复合材料制动盘的研究进展,并指出了现代轨道交通刹车材料设计与制造的研究热点及研究方向.     

中外轨道交通噪声标准探析

轨道交通作为当下人们出行的主要方式,缓解了城市交通压力,降低了能耗,但由此带来的噪声污染是限制其发展的主要原因。目前,世界各国都在探索降低轨道交通噪声的方法,制定适宜本国的噪声标准。以波哥大地铁1号线项目为研究背景,对主要国家的轨道交通噪声标准从测点位置、计算方法、计权方式等方面进行对比分析,同时进行噪声实测,根据不同噪声标准进行信号处理。结果表明,对同一噪声信号,各标准的等效连续声级相同,而随时间变化的声压级因时间计权不同而有所差异,根据这一分析结果提出适合波哥大地铁项目的设计噪声标准,为轨道交通噪声评价提供参考,也为中国建筑企业拓展海外项目提供依据。     

基于容差分析的武器装备体系耦合风险仿真研究

武器装备体系的耦合程度是衡量武器装备体系整体作战能力的一个重要指标。文中通过容差分析对武器装备性能的耦合风险进行了研究，通过实例对产生武器装备体系耦合风险的武器装备性能容差进行了模拟仿真，实例证明是有效的。     

空间热载荷作用下星载天线耦合动态影响分析

为了研究空间热载荷对星载天线刚柔耦合多体系统的扰动,根据抛物反射面几何特征,采用壳体单元有限元离散化法,并考虑壳体厚度方向上的温度变化,建立了有限元列式的热传导方程;引入与应变能有关的耦合项,利用拉格朗日法推导了星载天线系统的大范围刚柔耦合动力学方程,研究了温度载荷对星载天线多体系统的动力学特性影响。仿真结果表明:空间热效应引起了动态的温度载荷,与结构变形发生耦合,诱发耦合颤振,加剧柔性反射面的弹性振动,造成卫星姿态和天线指向的扰动,严重影响了星载天线的指向精度。结论对星载天线指向精度的分析与控制具有重要的理论价值及工程实际意义。     

流冰撞击力作用下列车–简支梁桥耦合振动分析

建立撞击荷载作用下列车‐桥梁系统动力分析模型,将现场实测的流冰撞击力时程作为系统的撞击荷载。通过计算机仿真分析,对流冰撞击作用下高速铁路桥梁的动力响应及其对桥上列车运行安全的影响进行研究。采用自编程序模拟列车过桥的全过程,计算分析7 m×24 m简支箱梁桥在流冰撞击力作用下动力响应及桥上高速列车的动力响应。计算结果表明,在实测流冰撞击力作用下,桥梁横向加速度以及车辆脱轨系数和轮重减载率等行车安全指标在列车速度250 km/h以上时超过容许值,说明流冰撞击作用对车桥系统耦合振动响应具有较大的影响。     

跨座式轻轨车与连续轨道梁空间振动分析

摘 要：提出了一种跨座式轻轨车与连续轨道梁空间耦合振动时域分析方法。桥梁采用常规有限单元模拟,跨座式轻轨车采用弹簧阻尼相连的多刚体模拟,可方便考虑走行轮、导向轮、稳定轮下轨道不平顺的影响,直接建立轻轨车－桥梁时变系统的空间振动方程,采用直接积分法同时求解轻轨车、桥梁的空间动力响应,并编制了相应的计算分析程序。以一联3×30 m的双线连续轨道梁为例,计算了轻轨车以不同车速通过双线轨道梁时全过程车桥动力响应。探讨了不同车速、单线行车、双线对开等不同工况对车桥动力响应的影响。计算结果表明：在设计行车速度下,轻轨车可安全舒适通过该连续轨道梁;桥梁具有良好的整体刚度。该方法可运用于跨座式轻轨车与其它大跨度桥梁的空间振动分析。     

地基土-两层偏心结构相互作用体系平扭耦联参数分析

为研究地基土－两层偏心结构相互作用体系的地震反应,本文对平扭耦联问题进行了参数分析。利用拉格朗日能量法建立了土－两层偏心结构相互作用体系平扭耦联运动方程,求得频域内解析解,并编制MATLAB程序,确定了影响两层偏心结构平扭耦联的主要参数,详细分析了扭平频率比Ω、偏心率B、偏心楼层位置和地基土特性等参数对相互作用体系弹性地震反应的影响规律,以及对平扭耦联程度的影响状况,得到了一些与刚基上偏心结构平扭耦联反应不同的参数影响规律,为工程计算和设计提供参考。     

高速列车悬挂系统连续混合控制策略的设计与仿真分析

在传统开关型半主动控制方法的基础上,提出了一种线性连续型天棚-加速度阻尼(skyhook-acceleration driven damping,SH-ADD)控制算法,用于提高半主动悬架在中高频区域内的控制效果。以国内某型高速动车组列车为原型,建立了两自由度1/4车横向动力学模型,用于设计改进的线性连续型SH-ADD半主动控制策略。以乘坐舒适性为控制目标,分别采用单频谐波激励和宽频轨道不平顺激励进行仿真,对不同控制策略作用下的系统振动特性进行对比分析。采用整车模型对控制算法进行了舒适度验证。研究结果表明:相比改进前的控制策略,新型半主动控制策略在高频范围内的振动控制效果更好。     

Vertical dynamic responses of a simply supported bridge subjected to a moving train with two‐wheelset vehicles using modal analysis method

The vertical dynamic responses of a simply supported bridge subjected to a moving train are investigated by means of the modal analysis method. Each vehicle of train is modelled as a four‐degree‐of‐freedom mass–spring–damper multi‐rigid body system with a car body and two wheelsets. The bridge, together with track, is modelled as a simply supported Bernoulli–Euler beam. The deflection of the beam is described by superimposing modes. The train and the beam are regarded as an entire dynamic system, in which the contact forces between wheelset and beam are considered as internal forces. The equations of vertical motion in matrix form with time‐dependent coefficients for this system are directly derived from the Hamilton's principle. The equations of motion are solved by Wilson‐θ method to obtain the dynamic responses for both the support beam and the moving train. Compared with the results previous reported, good agreement between the proposed method and the finite element method is obtained. Finally, the effects of beam mode number, vehicle number, beam top surface, and train velocity on the dynamic responses of the entire train and bridge coupling system are studied, and the dynamic responses of beam are given under the train moving with resonant velocity. Copyright © 2005 John Wiley & Sons, Ltd.     

土-偏心结构相互作用平扭耦联反应参数分析

建立了一种土一偏心结构相互作用简化模型，研究了考虑土一结构相互作用因素后结构平扭耦联反应。采用拉格朗日能量法推导了结构的运动方程，并结合算例，用振型分解法对结构的平扭耦联反应进行了分析，讨论了扭平频率比、偏心率和土一结构相互作用影响系数对结构平扭耦联反应的影响。计算结果表明，土一偏心结构相互作用体系与刚性地基上结构有明显差别，且随着地基土的变软，这些差别更为明显。     

兰州某地铁站蒸发冷却通风降温系统测试与应用研究

介绍了兰州某地铁站蒸发冷却通风降温系统,通过对该系统中机组进出风温度、站厅站台公共区环境温湿度、空气品质的实际测试,分析出该系统在实际运行过程中的情况.同时,对该系统中现存的一些问题,进行了分析说明,并提出了后期的优化改进措施.最终的测试结果表明,该蒸发冷却通风降温系统的运行情况较好,车站内公共区的降温效果良好,为以后...     

Image analysis to reveal crack development using a computer simulation of wear and rolling contact fatigue

Plastic flow of near‐surface rail material under contact loading is a feature of rail–wheel contact, and severe flow typically leads to both wear, and the initiation and development of small surface‐breaking cracks. This paper presents results from a ratcheting based computer simulation, which has been developed to allow the simultaneous investigation of wear, crack initiation and early crack propagation. To identify repeatably small crack‐like flaws, image analysis is applied to the visual representation of the wearing surface generated by the model. This representation shows a good similarity to traditional micrographs taken from sections of worn surfaces. The model clearly reveals the interaction of wear with crack development, processes which are linked because wear truncates surface‐breaking cracks, and can completely remove small surface‐breaking cracks.     

Limit analysis of viscoplastic flows using an extended general algorithm sequentially: convergence analysis and validation

The paper presents the extension of a general algorithm to limit analysis of viscoplastic flow problems. Based on the concept of sequential limit analysis, the paper treats viscoplastic flow problems as a sequence of limit analysis problems. In the formulation, a general plane-strain problem involving incompressible rigid-viscoplastic materials was stated in the upper bound formulation. The von Mises yield criterion was employed to model the yield behavior. In each step of a deformation sequence, limit load was computed by using a combined smoothing and successive approximation (CSSA) algorithm. Especially, the extended CSSA algorithm was shown to be unconditionally convergent by utilizing the Hölder inequality. Finally, numerical and analytical studies of a thick-walled cylinder under internal pressure were performed to demonstrate the applicability and accuracy of the computational procedure presented here. It is found that the computed limit loads are rigorous upper bounds and agree very well with the analytical solutions.