双层舷侧结构碰撞损伤过程研究

采用非线性动态响应分析方法,对船舶双层舷侧结构的碰撞损客 研究。研究中,结构材料采用线性强化弹性模型并计入了应变速率引起的材料强化,考虑了碰撞面的接触 与摩擦。     

湿陷性黄土地区公路构造物地基处理

针对湿陷性黄土地区土质的勘探、试验、湿陷等级确定、构造物类别划分等几个方面提出了湿陷性黄土公路构造物地基处理时应注意的一些问题并提出改进措施。     

沥青混凝土路面永久变形预测研究综述

作为沥青混凝土路面的主要损坏现象之一，车辙是在交通荷载反复作用下产生竖向永久变形的积累。在总结回顾车辙形成机理和影响因素的基础上，对现有永久变形预测方法进行了综述和简要评价，并重点讨论了SHRP预测模型，为我国的沥青混凝土路面设计提供参考。     

波形钢腹板PC组合箱梁结构设计与试验研究

通过对大尺寸波形钢腹板PC组合模型箱梁进行的设计和试验研究,得到一些有价值的结果,为波形钢腹板PC组合箱梁桥的设计和施工提供经验。结果表明,采用贴角焊将分段波形钢板连接成整体是可行的。波形钢腹板的纵向正应变值比混凝土顶板、底板小得多,数值上接近于零。试验梁的破坏形态为典型的弯曲破坏。     

高速公路交通生成预测的改进灰色马尔可夫模型

高速公路交通生成预测是进行高速公路网规划不可缺少的环节,传统的预测方法需要考虑人口、土地利用等因素,过程显得极为复杂。而灰色预测模型可以在基础资料缺乏的条件下可建立模型进行预测,但对于高速公路交通生成量这一类随机性、波动性较大的数据,使得拟合较差,预测精度降低。针对这些不足进行改进,提出改进的灰色马尔可夫预测方法。最后将该预测模型应用于高速公路网规划交通生成预测中,取得了良好的效果。     

基于动量定理的汽车碰撞事故再现模型抗扰性分析

基于摄动理论，应用3种常用的数学方法对基于动量定理建立的汽车碰撞事故模型的抗扰性进行分析。结果表明：对于特定模型在复杂的扰动条件下，采用不同的数学方法，处理效果截然不同。通过理论分析，建立了解决此类问题的方法，给出了数学表达式。经过对代表车型的实际分析，验证了该方法的有效性。     

Real-time capable vehicle-trailer coupling by algorithms for differential-algebraic equations

The real-time simulation of vehicle trains requires an accurate and numerically feasible representation of the vehicle-trailer coupling. Although the equations of motion for the chassis instances can be reduced to systems of ordinary differential equations, additional constraints on the relative motion of vehicle and trailer are introduced when considering the hitch. In this article, we present a strategy for the simulation of vehicle-trailer combinations, where the algebraic constraints of the coupling are treated explicitly. Although this approach allows exact modeling of the respective joint geometry and realistic calculation of the coupling forces, a suitable numerical algorithm is required in order to solve the resulting differential-algebraic system of index 3 in real-time. The implementation in a commercial vehicle dynamics program is discussed and real-time simulation results are shown, which prove its feasibility for different coupling joints and demanding driving maneuvers.     

沥青路面结构补强设计中的“反常现象”分析

利用极值理论和驻点分析方法,通过对沥青路面结构设计参数的分析,找出了产生"反常现象"的详细原因及其影响因素,并根据极值理论提出了"反常现象"时土基驻点弹性模量的具体求解方法。在沥青路面结构补强设计的实际工程中,这些结论为如何避免反常现象的发生提供了理论依据,并为沥青路面结构补强优化设计提供了理论依据。     

Modeling Travel Time Under ATIS Using Mixed Linear Models

The objective of this paper is to model travel time when drivers are equipped with pre-trip and/or en-route real-time traffic information/advice. A travel simulator with a realistic network and real historical congestion levels was used as a data collection tool. The network included 40 links and 25 nodes. This paper presents models of the origin-to-destination travel time and en-route short-term route (link) travel time under five different types and levels of advanced traveler information systems (ATIS). Mixed linear models with the repeated observation's technique were used in both models. Different covariance structures (including the independent case) were developed and compared. The effect of correlation was found significant in both models. The trip travel time analysis showed that as the level of information increases (adding en-route to the pre-trip and advice to the advice-free information), the average travel time decreases. The model estimates show that providing pre-trip and en-route traffic information with advice could result in significant savings in the overall travel time. The en-route short-term (link) travel time analysis showed that the en-route short-term (link) information has a good chance of being used and followed. The short-term qualitative information is more likely to be used than quantitative information. Learning and being familiar with the system that provides the information decreases en-route short-term delay.     

大断面衬砌台车在遂渝线龙凤隧道中的应用

文章介绍了遂渝铁路龙凤隧道大、变断面衬砌台车的结构设计组成、变断面方法和台车结构计算,其研究成果对同类隧道的施工具有参考价值。