基于有限元法的骨架式电动汽车车身可行性研究

本文基于国外某款微型车设计了骨架式电动汽车车身结构,通过有限元方法,分析了其静态刚度和模态特性。分析表明,其弯曲刚度大大高于参考弯曲刚度,扭转刚度略低于参考扭转刚度,但差别不大,一阶模态频率高于车身的振动频率范围。本文最终验证了该结构的基本性能均满足设计要求,为电动汽车车身的设计开发提供了一条科学、低成本的设计思路。     

扬子江客车WG6101EH节油基本原理及特点介绍

东风扬子江(WG6101EH)客车2007年4月在北京举办的CBFSC第二届中国客车节油大赛中获得了“大型高级城市客车节油型客车奖”,其成绩     

共赏阴极电泳车金旅展示"中国精品"

3月11日,上海2008 BAAV世界客车博览亚洲展会的金旅展台上,金旅大型客车整车车身阴极电泳线新闻发布会在这里拉开帷幕,经过整车阴极电泳打造的大客车全承载车身骨架也在这时被揭开其神秘的面纱.此项产品的发布标志着中国大型客车制造业的涂装工艺水平将提高到中档轿车的水平,达到国际客车生产一流的水平.     

基于有限元分析的新能源汽车侧面柱碰结构优化研究

文章针对侧面柱碰工况特点对汽车车身结构的传力路径进行了分析,并以某款新能源汽车为分析对象,采用HyperWorks软件搭建有限元仿真计算模型,对侧面柱碰工况车身的主要传力路径上的座椅横梁和中通道进行结构优化,使其车身侵入量和电池包的安全性能均得到明显改善.     

行走在目光的刀尖上——2007世界客车博览亚洲展览会获奖车型解读

BAAV2007年度客车大奖:厦门金龙XMQ6129Y作为整个展会首款揭幕的新车型,该车采用全承载式车身结构,利用骨架分散冲击力,提高了客车的安全系数,改善了车辆制动性能,提高车辆的行驶安全。国产客车中还不常见的挡风玻璃冷暖除霜雾系统、电动升降司机窗自动除霜功能、夜行倒车辅助灯等,体现对驾驶安全细节的周到考虑。     

输气管道站场应力分析

为确保管道在安装、试压、运行条件下安全,管道项目均应进行应力分析,以满足管道设计强度和柔性要求。文中以某输气管道工程输气站场为例,通过边界条件的简化处理并考虑埋地段与土壤的真实效应,在CAESARⅡ中建立了输气管道站场应力分析模型进行应力校核、清管工况应力分析。在安装工况、试压工况、运行工况以及清管工况条件下,站场应力模型满足应力校核需求,分析方法和结果也可以做为类似分析的参考。     

全承载客车：撑起中国客车安全的脊梁

安凯客车主持制定中国首个《客车全承载式车身结构要求》行业标准，随着该标准的即将出台，将规范我国全承载客车设计、生产、检测等各个环节，是中国全承载客车的“基本大法”，将指导中国全承载客车的未来发展     

箱型拱桥排架墩柱及横墙施工力学特性分析

拱桥的受力特征具有较大的特征性,在施工过程中对应力应变控制较为严格,通过对箱型拱桥施工安全风险响应研究,可具有针对性地加强施工过程的安全措施,增大其施工安全可靠度。以某箱型拱桥为例,基于有限元软件MIDAS对拱上排架墩柱及横墙进行数值计算分析,获取其施工力学特性。经计算可知在设置风缆后,拱肋稳定性增强;受力状况改善,最大拉应力与最大压应力均减小,最大压应力与最大拉应力小于材料的强度标准值,验证了结构施工其的安全稳定性。     

2012北京国际车展 纳威司达IC Bus展示美式校车典范

美国的校车一直被公认为世界上最安全的客车,除去醒目的黄色车身,以及车头、车尾顶部的黑色"SCHOOLBUS"("校车")标识,其安全特性更体现在车身及车厢内部的诸多细节设计。以纳威司达此次展出的两款ICBusTMCE系列校车(分别为18座和54座)为例,其底盘高度高于普通客车,可有效将碰撞产生的冲击力转移至车底;车身左侧配有停车标志牌,车身前后均配有警示灯;整个车身采用加强型钢结构,车头及车尾的保险杠均由厚实钢材制成,且在每侧车身各安装了     

美国客车专家纵论客车设计美学

从2002年下半年到2003年6月,国内客车业的几家明星企业金龙、宇通、中大先后面向社会及高校开展了客车设计大赛,大赛内容不仅包括客车车身造型设计、车身图案设计还包括了客车的内饰设计.从设计要求来看,各项设计都需要出众的美学知识,而开展客车设计大赛也反映了我国客车企业对客车美学的注重程度正在加强.     

客车车架结构设计与分析

文章根据客车车架设计理论和某长途客车底盘参数,设计出适用于客车底盘总成布置的三段式车架,并应用有限元分析软件Ansys WorkBench进行车架静力学分析,同时根据分析结果对车架薄弱部位进行了改进设计。     

Estimating the bus user time benefits of implementing a median busway: Methodology and case study

This paper presents a general framework to estimate the bus user time benefits of a median busway including the effects on travel time and access time. Unlike previous models, we take into account the effects of geometry and the interaction with the demand structure. Models for predicting the bus in-vehicle time benefits of a median dual carriageway busway against mixed traffic condition on 2 and 3 lanes roads are estimated using data from a case study in Santiago (Chile), using a bus travel time model empirically estimated and considering different base case situations, including mixed traffic operations and bus lanes. Results of the application show that the expected in-vehicle time savings of a median busway might be reduced by access time losses due to increased walking distances and road crossing delays. Also, that net time benefits can vary significantly according to the base situation and the structure of demand considered. These findings point out to the need of including a wider set of impacts when studying the benefits of median busways, beyond in-vehicle time savings only. The empirical work presented here is completely based on passive data coming from GPS and smartcards, what makes easier and cheaper to conduct this type of analysis as well as to do it with a comprehensive scope at an early stage of the development of a BRT project. This framework can be extended to other types of dedicated bus lanes provided that a corresponding bus travel time savings model is available.     

A structured flexible transit system for low demand areas

Public transit structure is traditionally designed to contain fixed bus routes and predetermined bus stations. This paper presents an alternative flexible-route transit system, in which each bus is allowed to travel across a predetermined area to serve passengers, while these bus service areas collectively form a hybrid “grand” structure that resembles hub-and-spoke and grid networks. We analyze the agency and user cost components of this proposed system in idealized square cities and seek the optimum network layout, service area of each bus, and bus headway, to minimize the total system cost. We compare the performance of the proposed transit system with those of comparable systems (e.g., fixed-route transit network and taxi service), and show how each system is advantageous under certain passenger demand levels. It is found out that under low-to-moderate demand levels, the proposed flexible-route system tends to have the lowest system cost.     

连续刚构桥健康监测数据的采集和处理

文章根据连续刚构桥的构造和受力特点,介绍了某连续刚构桥健康监测系统的数据采集方式和定时采集制度,同时对应力、挠度和加速度数据的后期处理方法进行了探讨,为其他同类桥梁的健康监测提供依据。     

营运大客车正面碰撞乘员伤害的研究

客车发生正面碰撞事故约占客车碰撞事故的50%~60%。利用LS-DYNA软件,建立了包括假人、安全带和安全气囊在内的大客车车体有限元模型,对不同速度下营运大客车的正面碰撞特性进行了模拟仿真计算,分析了无任何保护措施、佩戴安全带及佩戴安全带且安全气囊起爆三种事故形态下乘员头部HPC值、胸部压缩量和大腿骨轴向接触力等伤害值。研究结果表明,安全带对于驾驶员的保护意义重大,为营运大客车乘员保护设计以及合理制定营运大客车正面碰撞法规提供数据参考。     

A connected-vehicle-based dynamic control model for managing the bus bunching problem with capacity constraints

This paper describes a connected-vehicle-based system architecture which can provide more precise and comprehensive information on bus movements and passenger status. Then a dynamic control method is proposed using connected vehicle data. Traditionally, the bus bunching problem has been formulated into one of two types of optimization problem. The first uses total passenger time cost as the objective function and capacity, safe headway, and other factors as constraints. Due to the large number of scenarios considered, this type of framework is inefficient for real-time implementation. The other type uses headway adherence as the objective and applies a feedback control framework to minimize headway variations. Due to the simplicity in the formulation and solution algorithms, the headway-based models are more suitable for real-time transit operations. However, the headway-based feedback control framework proposed in the literature still assumes homogeneous conditions at all bus stations, and does not consider restricting passenger loads within the capacity constraints. In this paper, a dynamic control framework is proposed to improve not only headway adherence but also maintain the stability of passenger load within bus capacity in both homogenous and heterogeneous situations at bus stations. The study provides the stability conditions for optimal control with heterogeneous bus conditions and derives optimal control strategies to minimize passenger transit cost while maintaining vehicle loading within capacity constraints. The proposed model is validated with a numerical analysis and case study based on field data collected in Chengdu, China. The results show that the proposed model performs well on high-demand bus routes.     

Integrating bus services with mixed fleets

Conventional bus service (with fixed routes and schedules) has lower average cost than flexible bus service (with demand-responsive routes) at high demand densities. At low demand densities flexible bus service has lower average costs and provides convenient door-to-door service. Bus size and operation type are related since larger buses have lower average cost per passenger at higher demand densities. The operation type and other decisions are jointly optimized here for a bus transit system connecting a major terminal to local regions. Conventional and flexible bus sizes, conventional bus route spacings, areas of service zones for flexible buses, headways, and fleet sizes are jointly optimized in multi-dimensional nonlinear mixed integer optimization problems. To solve them, we propose a hybrid approach, which combines analytic optimization with a Genetic Algorithm. Numerical analysis confirms that the proposed method provides near-optimal solutions and shows how the proposed Mixed Fleet Variable Type Bus Operation (MFV) can reduce total cost compared to alternative operations such as Single Fleet Conventional Bus (SFC), Single Fleet Flexible Bus (SFF), Mixed Fleet Conventional Bus (MFC) and Mixed Fleet Flexible Bus (MFF). With consistent system-wide bus sizes, capital costs are reduced by sharing fleets over times and over regions. The sensitivity of results to several important parameters is also explored.     

The Intermittent Bus Lane signals setting within an area

Intermittent Bus Lane (IBL) used for bus priority is a lane in which the status of a given section changes according to the presence or not of a bus in its spatial domain: when a bus is approaching such a section, the status of that lane is changed to BUS lane, and after the bus moves out of the section, it becomes a normal lane again, open to general traffic. Therefore when bus services are not so frequent, general traffic will not suffer much, and bus priority can still be obtained. This measure can be operating at a single city block, but if all related control parameters along bus lines are considered together, more time gains can be obtained. In this paper, the basic structure and operation of IBL around a single intersection are briefly introduced, then the construction of an objective function and its relationships with the related priority control parameters along one bus line and their simplifications are described. Finally the calculations of the priority control parameters when there are several connected bus lines within an area and some simulation results are discussed.     

A methodology for planning bus service

A methodology to assist transportation planners in designing bus services is developed. The methodology is most relevant for use in locations where bus service of the type being studied does not currently exist and therefore no information is available on past choice behavior, or in instances when transferability of travel models estimated in another location is difficult. The methodology assesses the sensitivity of bus service characteristics upon intended bus usage using survey data collected in Orange County, California, by the Orange County Transit District (OCTD). The methodology is based on a nonparametric statistical test developed by Kolmogorov and Smirnov.Scenarios describing hypothetical operations of bus service are presented to survey respondents who indicate their intended levels of bus usage under each situation. Significant differences between the response distributions associated with pairs of scenarios are identified and potential ridership levels, as bus operations become more favorable, are assessed. Various user segments are then identified on the basis of their levels of intended bus usage and the corresponding marketing implications associated with each segment are discussed.     

船用控制台电磁兼容结构设计探讨

随着现代计算机网络技术和智能控制技术的不断进步,对电气控制设备箱体电磁兼容的要求越来越高。本文结合某电磁兼容控制台提出了一种电磁兼容的台体结构设计与同行探讨:设计横截面呈"U"字形及平面矩形的不锈钢框架,与碳钢材料台体壳壁门框孔处以焊接形式固定,配置电磁兼容密封材料,形成完整的电磁兼容结构。实践证明:电磁干扰测试和电磁敏感度测试符合设备正常工作要求,结构简洁,可靠性好,便于MACAD制造。