住建部行业标准《城市地下道路工程设计规范》编制研究

为规范我国城市地下道路工程设计,统一设计标准,通过国内外相关地下道路的规范及研究成果归纳、已有成熟设计经验总结以及专题研究等多种途径,研究编制了《城市地下道路工程设计规范》,就其设计原则、几何线形、出入口、交通设施、附属设施及防灾等与地面道路存在差异的方面作了规定。从总体技术路线、规范框架体系、规范特点及新颖性三方面阐述了该规范的研究框架。该规范的编制将填补我国当前城市地下道路工程领域规范的空白,对未来提高城市地下道路工程设计质量,保障运营安全等具有重要意义。     

基于车辆平顺性分析的橡胶衬套动态特性建模

橡胶衬套的动态特性与载荷的激振频率、幅值等因素相关,其模型的准确性影响车辆平顺性的仿真精度。建立了包含材料弹性、粘弹性与弹塑性的橡胶衬套动态模型,分别采用多项式、分数导数与Bouc-wen模型描述橡胶衬套的弹性、频率相关性及振幅相关性。通过参数辨识确定衬套模型参数并进行仿真,验证了所建模型的准确性。     

停车让行交叉口机动车接受间隙和拒绝间隙分布特征

为了给出停车让行交叉口机动车的临界间隙值,调查了上海市不同区域(中心区、郊区等)和不同类型(十字形、T形)的14个交叉口,提取各交叉口不同流向(主路左转、支路直行、支路左转)交通流之间的穿越行为特征数据.基于Raff方法和极大似然估计法,对接受间隙和拒绝间隙数据进行统计分析,从而获得了不同类型交叉口不同流向的临界间隙值,将实测值与HCM2010中的推荐值进行比较.统计分析结果表明:T形交叉口和十字形交叉口的接受间隙和拒绝间隙明显不同,其中342型交叉口各流向的接受间隙和拒绝间隙值明显大于322型交叉口各流向的接受间隙和拒绝间隙值;支路左转车流的实测值大于HCM2010的推荐值,而其他流向的实测值均小于HCM2010推荐值;不同区域的交叉口各流向临界间隙值不同,越靠近外环,机动车临界间隙越大.     

钢管混凝土拱桥地震响应分析的参数研究

松岙大桥主桥为260 m的钢管混凝土提篮拱桥,以该桥为研究背景分析桥梁结构的地震时程响应,应用MAT-LAB语言编写了3个程序:人造地震动、采用频域积分法将加速度时程转化为位移时程、由确定的加速度时程求其加速度反应谱,并采用SAP2000为计算平台对上述几种情况下的桥梁地震响应做了对比分析。分析结果显示,大跨度桥梁对于不同的地震波、采用不同的阻尼算法、是否考虑结构的行波效应、是否考虑结构的几何非线性其地震响应差别较大,在分析中应针对具体的桥梁结构确定合理的参数与求解方法。     

拼焊车门内板冲压成形性分析

首先介绍了采用不等厚拼焊板的车门内板在冲压成形过程中出现的问题;接着对缺陷区域进行主应变测量和安全成形裕度预测.结果表明,车门内板出现破裂和起皱的主要原因是拉延筋阻力不足和厚、薄两侧板料的流动阻力不均.最后提出采取局部调整拉延筋阻力和压边力等措施来改善车门内板冲压成形性.     

基于六通道道路模拟机的重型汽车路面激励再现试验

利用INSTBON六通道道路模拟机对三轴式重型汽车进行了路面激励再现研究.介绍了路面激励再现的基本原理,分析了在道路信号采集与处理、试验系统频响特性识别、迭代运算及迭代质量评价等环节遇到的问题.以安徽定远汽车试验场的鱼鳞坑路面为例进行了模拟迭代试验,经过23次迭代后各测点的迭代误差均小于10%,即模拟响应与道路响应的功率谱密度基本吻合,实现了对实际路面激励的模拟.     

基于ACCESS的斜拉桥病害数据库系统开发

针对目前高速公路桥梁管理系统无法对悬索桥、斜拉桥的上部、下部结构的重点部位提供病害管理的情况,依据斜拉桥桥梁养护检测中的病害特点及类型,利用ACCESS工具开发出斜拉桥病害数据库,提供病害录入、查询、统计、分析等功能,解决了斜拉桥重点部位病害动态管理的问题.     

基于逆向工程再设计的汽车电动内藏天窗研发

以汽车电动内藏天窗为基础模型,利用逆向工程技术,建立了CAD模型;运用快速成型技术进行校核、验证和装配,完善该模型;在分析内藏天窗的基本结构和工作原理的基础上,论述了再设计的思路和实现措施,提出该内藏天窗模型与汽车顶篷匹配的解决办法,最终设计出特定车型的原厂配套内藏天窗.     

Adaptive neuron control using an integrated error approach with application to active suspensions

This paper proposes a new neuron control strategy for an active vehicle suspension system, with the emphasis on the study of multivariable and uncertain suspension characteristics. The novelty of this strategy is in the use of integrated error, which consists of multiple output errors in the regulated plant. By combining the integrated error approach with the traditional neuron control (TNC), integrated error neuron control (IENC) is presented. It provides a direct control to the multiple outputs of the control plant simultaneously. Taking a quarter-car model as an example, the proposed control strategy is applied and comparative simulations are carried out with various vehicle parameters and road input conditions. Simulation results prove the effectiveness and robustness of the proposed IENC method. In addition, the newly proposed neuron scheme provides a simple yet efficient new possibility for the control of a class of uncertain multivariable systems similar to an active vehicle suspension.     

Transient characteristics of emissions during engine start/stop operation employing a conventional gasoline engine for HEV application

In this paper, we investigate the transient characteristics of combustion and emissions during engine start/stop operations in hybrid electric vehicle (HEV) applications. Hydrocarbon (HC) emissions during the initial 2^nd∼9^th cycles are found to be significantly greater when the engine is quickly started under the original engine calibration mode. Lower intake manifold absolute pressure (MAP) was also found to cause larger residual gas dilution and poor combustion, resulting in a higher HC concentration when the cranking speed was increased. The post-catalyst HC concentration was found in the way of initially decrease and then to increase again as the cranking speed was increased. A lowest concentration value was achieved at a cranking speed of 1000 r/min. Engine shut-down by fuel cut-off was shown to produce lower emissions than shut-down by ignition cut-off as one can avoid misfire of the last fuel injection cycle. The fuel deposited during the stop process seems to impact engine restart enrichment mostly during the initial 0.7 s for this engine, whose performance is dominated by the MAP transition characteristic and the time coefficient for fuel vaporization in this time period