侧风环境下车辆动态响应研究

文章为了研究侧风环境下车辆动态响应,建立了二自由度车辆动态模型,并对车辆横摆角速度和侧向速度等指标进行了推导,给出了计算公式,编制了计算程序。以货车和轿车作为实例进行了计算和分析。研究结果表明:气动中心位于质心之后对行车安全最有利;货车受侧风的影响较大,轿车受侧风的影响较小。     

Sea space capacity and operation strategy analysis system

Sea space planning and congestion management is receiving more attention. However, little work on sea space capacity and strategy analyses can be found in the literature. Compared to other transportation systems, a sea space system has some special features that require consideration. The system capacity also depends on the pattern of traffic using the system. In this paper, we model a sea space as a directional network and capacity models for berthing areas, anchorage areas, fairways and their intersections, as well as the entire sea space system are developed. These models can be used to compute capacity for any given traffic pattern which can be extracted from vessel trip records or from traffic forecasts. To implement these models, a software system called Sea Space Capacity and Strategy Analysis System (SCSAS) has been developed in Visual C + + and is now being used in Singapore.     

超大跨度跨海大桥高程控制网研究与应用

针对当前沿海地区连岛工程跨度大的特点, 文章提出一种基于 GPS 和测量机器人 5km 超大跨度高程传递方法, 对竖直角和边长精度之间的关系进行了分析研究, 得出了竖直角越接近 90°, 边长对高差影响越小, 竖直角在一定范围内完全可以使用 GPS 方法; 并对观测方案进行优化处理, 提高了观测精度和作业效率, 完成了超大跨度高程传递, 满足国家二等水准精度要求。     

The role of access and egress in passenger overall satisfaction with high speed rail

Passenger satisfaction is critical to ridership growth of high speed rail (HSR). Each HSR trip includes at least four segments: access to HSR stations, waiting, line-haul, and egress from HSR stations. Satisfaction with any segment influences the HSR passenger experience. Previous studies often focus on passenger satisfaction with the line-haul segment, but overlook the effects of all four segments on overall HSR satisfaction, especially access and egress. Using a path analysis on the data collected from the Shanghai-Nanjing HSR corridor in 2016, this study explores the influence of access and egress segments on overall HSR satisfaction and the correlates of satisfaction with HSR access and egress segments. We find that HSR line-haul satisfaction dominates overall HSR satisfaction; HSR access and egress satisfaction together have an equivalent effect. Travel time and route familiarity are important to both access and egress satisfaction. Mode choice affects satisfaction with HSR egress, with egress by car carrying the largest utility of egress satisfaction, followed by rail transit, taxi, and then bus. Thus, to improve HSR experience, traveler information service and the integration of HSR with urban transportation system are critical.

     

Travel choices in alcohol-related situations in Virginia

Transportation - Using survey data from 3004 respondents aged 21 and older in Northern Virginia, Richmond, and the Tidewater area, this paper identifies factors associated with respondents’...     

我国行人过街绿闪信号的设置方式与路权分析

在行人过街交通信号中加入绿闪信号已经是国内较为常见的设置方式,但是绿闪信号究竟代表什么含义、其时长应该如何设置和计算,目前尚无统一定论。本文首先整理了绿闪信号在我国的设置现状,接着分析了国内涉及到绿闪信号的相关法规标准,然后对比了其他典型国家或地区的行人过街清空信号设置方式,总结出"绿闪"、"红闪"和"持续红灯"三种主要的设置类型,并对其进行了相应的优劣势分析。最后,从行人清空信号期间的人行横道路权争议入手,综合上述分析结果,提出了较为适宜我国现状的行人清空信号设置方法,并对健全完善我国行人清空信号设置规范提出了建议。     

13000 DWT多用途重吊船总布置与稳性研究

为满足日益重型化、大型化的货物运输要求,配置2台450 t重型吊机,并对总布置进行针对性研究,优化货舱和载货平台设计获得超大的载货空间,通过优化分舱、合理选取敞口模式下的吃水与初稳性高等措施,成功解决总布置设计带来的破舱稳性、重货失落稳性、敞口航行稳性等方面的难题,对类似船型的开发具有借鉴意义。     

“一带一路”中老泰铁路运输风险评价及保费研究

随着“一带一路”设施联通建设的不断推进,作为泛亚铁路中线工程的中老泰铁路也是其中重要的一部分。为研究一带一路中老泰铁路货物运输风险以及相关保费计算,本文首先采用层次分析法得到铁路货物运输过程中存在的政治因素、气候因素、运维因素和自然力因素的风险以及不同风险因素组合的权重;其次基于N-K模型对风险进行耦合,并且结合权重计算风险耦合值,根据风险耦合值划分风险区间,不同风险区间对应的附加费率不同,最后利用保费计算公式可以得到保险费用。本文末以中老泰铁路运输水果为例,基于不同风险因素的耦合得到15个风险耦合值,并计算保费,得出不同风险下的保费结果。     

接触压力分布对预应力弯曲孔道摩阻损失的影响

基于弹性接触分析,指出预应力筋与弯曲孔道的接触压力为非均匀分布.为探讨压力分布状况对摩阻力的影响,提出余弦、二次抛物线及椭圆等3种非均匀分布假设,分别推导了各自的接触压力表达式及摩阻力计算公式,并与均匀分布下摩阻力计算值进行了比较分析.结果表明,接触压力均匀分布假设并不会导致桥规预应力摩阻损失公式对摩阻损失的低估;当孔道转角较小时,该公式是适用的.     

压弯复杂应力下焊趾局部应力-应变研究

通过对模拟结合壳典型部位的焊接试件进行加载试验,分析了压应力对局部应力应变特征的影响,结果显示,焊趾处名义应力相同条件下,局部应力应变值与施加的载荷形式有关.同时,对此试件进行的弹塑性有限元分析,得到了与试验结果基本吻合的规律.由此得出,压应力与弯曲应力的比值较小时,对焊趾处局部应力应变产生的影响可忽略;比值较大时,产生的影响不可忽略.