Tractor-semitrailer model for vehicles carrying liquids

This article presents a model for solving solid-fluid interactions in vehicles carrying liquids. A tractor-semitrailer model is developed by incorporating suspension systems and tire dynamics. Owing to the solid-fluid interaction, equations of motion for the vehicle system are coupled. To simplify the complicated solution procedure, the coupled equations are solved separately using two different codes. Each code is analyzed separately; but as the parameters of the two codes depend on each other, the codes must be connected at the end of each time step. To determine the dynamic behavior of the system, different braking moments are applied. As the braking moments increase, braking time decreases. However, it turns out that increasing the braking moment to more than a certain level produces no significant results. It is also shown that vehicles carrying fluids need a greater amount of braking moments in comparison to vehicles carrying solids during braking. In addition, as the level of the fluid inside the tanker increases, from one-third to two-third of the tanker's volume, the sloshing forces applied to the tanker's walls increase. It was also concluded that the strategy used in this article to solve for the solid-fluid interaction by incorporating vehicle dynamic effects represents an effective method for determining the dynamic behavior of vehicles carrying fluids in other critical maneuvers.     

论道路交通安全文化的建设

道路交通安全文化建设是提升当代道路交通安全管理水平的新途径。首先分析了道路交通安全文化的内涵,论述了道路交通安全文化建设的必要性,最后从战略、建设主体、建设渠道以及评价4个角度论述了道路交通安全文化建设对策。     

高速公路车速与交通安全

从运行车速、超速行驶、速度差以及限速等与车速有关的方面分析了车速与交通安全的关系,得出了相关的结论。     

连续下坡路段交通安全的改善措施

分析运营阶段连续下坡路段事故特征以及存在的突出问题,借鉴国内外典型连续下坡路段安全改造的经验,提出了一系列连续下坡路段的安全改善措施。道路管理部门可以合理运用这些措施,减少交通事故,提高连续下坡路段的安全性能。     

提前右转的科学性论证

分析了十字交叉路口直行车流和右转车流产生交通分流冲突的原因,以及因此而造成的交通事故隐患。为解决这个问题,笔者在借鉴国内外交通冲突技术(TCT)的理论研究成果的基础上,建立了十字路口直行车流和右转车流分流冲突模型,并用北京市火神庙十字路口的调查统计数据对模型进行了验证,从而在理论上证明了"提前右转"对于减少交通冲突,提高交叉路口安全的科学性,对于交叉路口设计和改造具有较强的指导意义。     

钢管混凝土拱桥整体稳定性分析

对某钢管混凝土拱桥不同的稳定性设计方案进行了介绍,利用有限元方法对钢管拱施工、成桥各阶段的整体稳定性进行了空间分析,并讨论了影响整体稳定性的因素,希望通过比选找出最佳的稳定性方案。     

不等时距GM(1,1)模型在预测输气管道腐蚀中的应用

根据等时距GM(1,1)模型建立了不等时距GM(1,1)预测模型,该模型可应用于利用腐蚀指标的原始数据来预测以后的输气管道腐蚀情况。验证表明:不等时距灰色模型扩大了等时距灰色模型的应用范围,在小样本的情况下同样可以做出较准确预测,为输气管道的防腐提供了可靠的依据。     

The Impact of Travel Time Information on Travelers’ Learning under Uncertainty

In this work, laboratory experiment was conducted in order to evaluate the effect of feedback on decision-making under uncertainty, with and without provided information about travel times. We discuss the prediction of travelers’ response to uncertainty in two route–choice situations. In the first situation travelers are faced with a route–choice problem in which travel times are uncertain but some external information about routes’ travel times is provided. The second situation takes place in a more uncertain environment in which external information about travel times is not provided, and the travelers’ only source of information is their own experience. Experimental results are in conflict with the paradigm about traveler information systems: As a consequence of information, the propensity of travelers to minimize expected travel time is not necessarily increased. Providing travelers with static information about expected travel times reveals an increase in the heterogeneity of travelers’ choices and reduces the maximization rate.     

Mixed Logit模型及其在交通方式分担中的应用研究

离散选择模型的典型代表Logit模型简洁易用的特点使其在经济、交通等领域得到了广泛的应用，但同时Logit模型的两个重要缺陷限制了其应用范围。在分析了Logit模型固有的两个缺陷和Mixed Logit模型的良好性质后，比较了Logit模型与Mixed Logit模型的差异，对Mixed Logit模型的算法进行了研究，并借助SAS统计软件提供的仿真算法给出了详细的工程实践应用范例。结果表明，Mixed Logit模型有着更丰富的物理含义，对个人出行交通方式选择行为的描述更符合实际。     

用于汽车纵向运动控制的传动系统模型简化与分析

针对汽车纵向运动控制系统特点，采用线性化方法对比分析传动系统各部件对系统传递性的影响，总结出适合汽车纵向运动控制的简化数学模型。并基于简化模型，应用灵敏度理论分析了系统传递特性对模型中各参数的敏感性。