Virtual durability test rigs for automotive engineering

In recent years so-called ‘virtual test rigs’ have become more and more important in the development process of cars and trucks. Originally, the idea was to substitute expensive durability tests with computer simulation. Meanwhile, the focus has changed towards a more cooperative usage of numerical and laboratory rig simulation. For many safety critical issues laboratory tests remain indispensable. In early development stages, when no physical prototypes are available yet, numerical simulation is used to analyse and optimise the design. In this paper, we show how to build numerical simulation models of complex servo-hydraulic test systems and their test specimen using multi-body simulation for the mechanics in combination with simulation models for the hydraulics and controls. We illustrate this at two industrial application examples: a spindle-coupled passenger car suspension rig and a tyre-coupled full vehicle rig. We show how the simulation models are used to design and optimise better test rigs and to support the test rig operation by preparing the physical tests with new specimen, i.e. by performing numerical simulations including numerical drive file iteration before the physical tests start.     

基于分形插值方法的城市轨道交通车站客流拟合与仿真

城市轨道交通车站客流量的变化具有复杂的非线性特点,通过对某些车站一天的客流量时间序列的分析,发现其客流量的变化具有自相似性,并且满足某种拟周期性。本文采用迭代函数系统模型描述城市轨道交通车站客流量的变化特征,用计算机自动求解该迭代函数系统的相关参数,在此基础上采用分形插值的方法模拟产生动态的客流。通过与实际客流调查数据的对比分析可以看出,该方法模拟产生的客流不仅与实际客流较好地吻合,而且能更好地描述客流的非线性特征。     

An assessment of the performance of the European long intermodal freight trains (LIFTS)

Intermodal rail/road freight transport has always been considered as a competitive alternative to its road freight counterpart in the European medium- to long-distance corridors (markets). Such consideration has been based on the increasing competitiveness of some innovative rail services and the existing and prospective performance of both modes in terms of the full social – internal or operational and external – costs. The most recent innovation of rail technologies and related services launched by some European railway companies, still at the conceptual level, is the Long Intermodal Freight Train (LIFT). This is supposed to be a block train operating in long-distance corridors (markets) with a substantial and regular freight demand.This paper develops analytical models for assessing the performance of the LIFTs, the already-operating Conventional Intermodal Freight Trains (CIFTs), and their road counterpart as well. The performance consists of the full – internal (private) and external – costs of the door-to-door delivery of loading units – containers, swap-bodies, and semi-trailers. The internal costs embrace the operational costs of the transport (rail and road) and intermodal terminal operators. The external costs include the costs of the impacts of door-to-door delivery of loading units on society and the environment. These negative externalities include noise, air pollution, traffic accidents, and congestion.The models are applied to a simplified version of intermodal and road transport system using inputs from the European freight transport sector. The aims are to compare the full costs of particular modalities in order to investigate the potential of the LIFTs as compared with the CIFTs in improving the internal efficiency of the rail freight sector and its competitiveness with respect to its road counterpart. In addition, the paper attempts to assess some effects on the potential modal shift of EU (European Union) transport policies on internalizing transport externalities.     

高黎贡山隧道1号竖井设计及分析

为了满足高黎贡山隧道竖井施工任务要求，综合隧道所处环境及竖井能力需求，按照竖井井口、井筒、井下3方面统筹考虑的总体设计思路，提出高黎贡山隧道1号竖井设计关键问题的解决方案： 1）根据井口地形、地貌条件及提升设备、井口车场布置要求，合理布置井口场坪； 2）根据竖井功能定位，竖井宜采用主副井模式； 3）根据井下施工的出渣量、材料数量、人员进出量等综合考虑竖井断面尺寸； 4）当地质条件、水文地质条件允许时，竖井宜采用短段掘砌混合作业法施工，设置模筑混凝土井壁； 5）竖井提升设备宜按井下施工期间的要求考虑，建井期间各设备之间能力应匹配； 6）竖井施工能力应满足井下施工期间出渣、进料要求，并留有富余； 7）井底车场应结合运输方式及进料、出渣等功能要求确定； 8）竖井安全保障应首要解决地下水问题。目前高黎贡山隧道1号竖井主井已完成建井，结果表明铁路隧道竖井按照以上设计方法及思路是可行的。     

深圳地区软粘土变形参数研究

根据深圳地区15个软土处理工点的4000多组试验数据,对软土的物理指标和变形指标进行统计分析。结果表明:压缩系数、变形模量和压缩指数的变异系数很大,其算术平均值的误差较大,不宜直接用于工程计算;含水量的变异系数很小,且与压缩参数有良好的相关性,可以较好地推算软土变形参数。因此,建议在实际工程中,如果没有软土的变形实验数据,可以直接根据软土的含水量进行估算;对于有实验数据的情况,将实验得到的变形参数和根据土样含水量估算的变形参数进行比较,剔除与估算参数相差较大的试验数据,将余下的数据取平均作为所需要的变形参数。     

基于安全库存管理的钢板采购订单优化

为合理安排钢板采购，有效降低库存占用，开展基于安全库存管理的钢板采购订单（Purchase Order，PO）优化研究。基于钢板采购流程和采购目标，分析钢板安全库存影响因素。根据钢板管理业务流程，阐述钢板安全库存管理流程，对钢板PO进行优化，帮助船厂更好地实现钢板管理。     

基于FSA的舰艇安全风险决策研究

舰艇装备系统结构复杂,在使用过程中,存在着各方面的安全风险。FSA是一种帮助制定合理的规则和提供可能的风险控制方案的综合性评价工具。当以维修作为风险控制的主要手段时,可以优化FSA循环的步骤,采取并行的方式,解决保障资源有限的维修决策问题。     

碳纤维布与钢板复合加固钢筋混凝土梁刚度分析

碳纤维布与钢板复合加固是一种新型的加固方法,可应用于桥梁等大跨度梁的加固。本文对12根碳纤维布与钢板复合加固钢筋混凝土梁进行了试验研究,结果表明,碳纤维布与钢板复合加固方法可较大幅度地提高钢筋混凝土梁的截面刚度,减小其变形。在试验研究的基础上,分析钢筋混凝土梁在碳纤维布与钢板复合加固后截面刚度的变化规律,并运用刚度解析法对截面刚度进行了计算,同时结合相关试验资料的统计分析,提出复合加固梁截面刚度的简化计算公式。其计算结果与试验结果吻合较好,可为实际工程应用提供参考。     

基于令牌环网络拓扑结构的地铁电动客车网络监控系统

列车网络控制系统目前已经成为城市轨道车辆控制的主要方案之一,该系统将车辆主要电气设备的监控信息通过网络连接的终端融合在一起,便于设备控制、维护和司机操作。本文介绍基于ARCnet网络技术以及令牌环传输协议的网络监控技术,最后介绍地铁电动客车的网络基本构成和节点控制方案。     

矿物掺合料对除冰盐环境下混凝土氯离子扩散中劣化效应系数的影响

采用化学分析方法,测定了高强混凝土(HSC)和高性能混凝土(HPC)在3种氯盐环境中的自由氯离子分布规律。根据F ick第二扩散定律和相关公式计算了混凝土中氯离子扩散的劣化效应系数(K)。结果表明:在除冰盐环境下,不掺掺合料的HSC存在劣化现象;掺加粉煤灰(FA)的HPC不存在劣化现象;掺加硅灰(SF)能减小混凝土的劣化程度,掺量为5%时效果最佳;双掺硅灰和粉煤灰(SF FA)的HPC不存在劣化现象。