轨道交通站场BIM设计建模探索

轨道交通站场BIM设计专业软件较为欠缺,为了提高设计效率,统一设计标准及数据格式,基于Bentley的基础图形平台Microstation进行二次开发,对站场设计构件进行对象化、实体化处理,并提出站场股道设计、路基设计、构件设备库等BIM设计方面的技术路线和解决思路.研究表明,在参考股道位置的基础上,软件可自动化生成站...     

牵引供电系统串并联电容调压交互影响分析

本文在分析串联电容和并联电容补偿调压原理和特性的基础上,定量分析了串联电容和并联电容共同调压时的交互影响,指出串并补之间存在交互影响的根本原因是并补使流过串补的无功电流减少,串补使系统的等效阻抗降低.仿真研究表明:负荷电流大小和串联电容补偿度是影响串并补交互影响的关键因素:串并补共同作用可以降低系统电压的波动范围.     

软土地基高速公路扩建中新老路堤相互作用数值分析

采用弹塑性有限元方法分析了老路边坡开挖和加宽部分路堤填筑对老路变形特性的影响。计算结果表明：原有路堤边坡削坡和台阶开挖将会使得老路中心的竖向沉降略有增加，坡脚侧向位移回缩，且不同开挖方式对原有路堤影响不同；加宽部分路堤的填筑将会使得老路中心上抬，路肩点发生较大附加沉降，引起老路路肩与路中心之间产生过大的附加差异沉降，明显加大路面横坡，极易导致对老路路堤、路面的拉裂，降低道路等级，必须采用合适的软基处理方案对加宽部分软基进行处理。另外，宽路堤的变形特性不同于窄路堤，其沉降呈中央小两边大的形式，并且最大沉降位置随路堤高度的增加向路堤中央移动，了解宽路堤变形的这一特性有助于其软基处理方案以及加固效果监测方案的优化。     

INFLUENCE OF ETHANOL ON TOXICOKINETICS OF ACONITINE

ＩＮＦＬＵＥＮＣＥＯＦＥＴＨＡＮＯＬＯＮＴＯＸＩＣＯＫＩＮＥＴＩＣＳＯＦＡＣＯＮＩＴＩＮＥＸｕＷｅｉ；ＨｕＢｉｎｇｗｅｉ；ＣｈｅＸｉａｎｇｍｉｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＴｏｘｉｃｏｌｏｇｙ，ＦａｃｕｌｔｙｏｆＦｏｒｅｎｓｉｃＭｅｄｉｃｉｎｅ，Ｘｉ...     

Appraising large-scale investments in a metropolitan transportation system

A package of large-scale investments in the transportation infrastructure in the Stockholm metropolitan region is currently being proposed. It contains new investments in the railway and subway systems as well as new links in the road system. This paper deals with the issue of appraising this kind of investment program. One major problem is the lack of a unique standard method, and it is argued that several tools should be used in a practical evaluation of large-scale investments in the transportation system.Four different approaches are presented and related to each other. First, one study uses a network-based mode-split/assignment model with a fixed trip matrix. The second study is complementary, as its aim is to also trace the impacts on the spatial distribution of population and jobs by applying an integrated transportation and land use model. Third, the long-run effects of the investments on regional economic growth are discussed within the framework of regional production functions. Fourth, an alternative approach is used, in which benefits from the investments are assessed through their estimated influence on aggregate land values.Abbreviations RA Reference Alternative - IP Investment Proposal - IMREL Integrated Model of Residential and Employment Location - RPFM Regional Production Function Model An earlier version of this paper was presented at the 31th European Congress of the Regional Science Association, Lisbon, August 1991.     

Application of plastic framing requirements for polar ships

A new International Association of Classification Societies (ICAS) standard for Polar Ship design, in the form of a Unified Requirement is being developed by an international committee with representatives from many classification societies and with the active participation of many polar nations. The framing structural requirements have been developed by a combination of analysis of existing rules and ships, finite element analysis and analytical solutions of plastic collapse mechanisms. This paper describes the use of the rule formulae in designs. The formulae contain interactions between shear and bending and give the designer options and flexibility in satisfying the strength requirements. Effective design requires knowledge of the effects, and the possible approaches to reach a satisfactory design.     

新型160 km·h~(-1)集装箱专用平车动力学性能分析

针对研制中的时速160 km新型快速集装箱专用平车存在的横向运动稳定性差、对线路的动力作用相对较大等问题,提出如下4项改进措施优化车辆设计.①采用增大车体抗扭刚度和侧滚转动惯量的侧墙结构;②一系悬挂采用单拉杆加钢弹簧结构的弹性定位方式;③适当减小二系悬挂的横向刚度;④选择常接触弹性旁承参数时兼顾车辆的横向运动稳定性和曲线通过性能.建立平车与轨道动态相互作用分析模型,并采用机车车辆-轨道耦合动力学仿真分析软件分析改进后时速160 km新型快速集装箱专用平车的动力学性能.仿真结果表明:改进后的时速160 km新型快速集装箱专用平车具有良好的横向运动稳定性、曲线通过件能和直线运行平稳性,轮轨动力作用较低;以时速50 km侧向通过12#固定辙叉道岔和以时速160 km通过轨道低接头时,对线路的动力作用均满足设计规范要求.     

重庆轨道交通单轨系统弓网配合的研究及改造

重庆轨道交通2号线跨座式单轨交通系统在弓网配合方面出现集电器滑块磨耗不均匀问题,分析其形成的原因,提出接触网拉出值改造方法,并讨论改造后的效果。     

刚性接触网磨耗分析

以国内第一条采用刚性接触网的广州地铁2号线为例,通过分析发现开通后的6年时间里,出现最严重的问题就是接触线的磨耗.阐述磨耗产生的原因,对如何缓解磨耗提出建议.     

基于桥梁基准有限元模型的列车-桥梁空间耦合振动分析

以武汉天兴州公铁两用大桥为研究背景,基于大桥通车前环境振动试验得到的模态识别参数对依据设计图纸建立的桥梁初始有限元模型进行修正,建立反映桥梁真实动力行为的基准有限元模型。基于该基准有限元模型,建立大桥列车—桥梁空间耦合振动方程,采用模态综合法,进行单线行车、双线并行和双线对开工况下的列车—桥梁空间耦合振动分析,并对车辆运行的舒适性和安全性进行评估。结果表明,在上述各工况下,列车通过该桥时,车辆的各项动力学性能指标值均满足规范规定要求,列车行驶的安全性和平稳性均较好;桥梁中跨跨中最大横向位移为1.52 cm,最大竖向位移为10.5 cm,相应的竖向、横向挠跨比分别为1/4 800和1/33 158,均满足铁路桥梁检定规范要求,说明该桥具有足够的横向和竖向刚度。