中国城市轨道交通运营企业官方网站影响力评价

运用网络链接分析方法、网络影响因子测度方法和网络流量分析方法,对我国已运营轨道交通的各城市轨道交通运营企业官方网站的影响力进行了评价;同时将链接分析和网络影响因子测度结果与网络流量排名进行了比较.对当前网站建设进行了讨论并提出了建议.     

随机海况下的船体结构疲劳裂纹扩展

传统的疲劳问题一般都是采用S—N曲线及Miner累计损伤理论进行的,文章在基于断裂力学的基础上,通过权函数法来计算应力沿裂纹面的非线性效应力强度因子,鉴于船舶在海洋环境中受到载荷的随机性,充分考虑加载次序、过载峰和应力比等对裂纹扩展的影响,给出了船舶结构疲劳裂纹在随机载荷下的扩展寿命的计算过程。     

LNG运输船作为浮式储存装置的适应性评估研究

采用OCIMF方法和水动力分析法,对3万方LNG运输船靠泊码头作为FSU适应性评估进行了研究,运用AQWA软件并结合码头实际情况对已有系泊方案进行了优化设计。从碰垫选型、系泊方案分析、总管与软管连接兼容性和设备维护保养等方面评估了该轮作为FSU的适应性,并结合船舶、码头实际配备情况提出相应的建议措施,为作为FSU安全作业提供保障。     

环口板加强T形管节点抗冲击性能机理研究

为深入研究环口板加强后T形管节点的抗冲击性能,文章采用试验研究和有限元研究相结合的方法,对未加强和环口板加强T形管节点的抗冲击性能进行了比较研究,旨在确定环口板加强节点受冲击后的典型破坏模态;并通过对变形发展、局部变形和整体变形的区分、冲击力-位移关系曲线、能量耗散等分析,揭示环口板加强节点的抗冲击工作机理,研究环口板的局部加强作用,确定环口板加强方式的有效性,可为管结构抗冲击设计和加固维护提供参考。     

船首外飘砰击设计载荷直接计算

文章结合三维线性势流理论和砰击速度的长期分析方法,求解出船体外飘位置的设计砰击速度;以首垂线和静水面交点处的设计砰击速度为目标值,给出了用于确定船首外飘砰击设计载荷的等效设计波,进而得到了设计状态下船体外飘剖面与波面相对运动关系;将船体剖面与波面间的相对运动关系等效转化为船体剖面与静水面的相对运动,利用显式有限元方法实现了外飘剖面砰击设计载荷的预报。针对直接计算方法中涉及的设计砰击速度、砰击压力和砰击压力系数,对比分析了文中结果和相应的规范值或试验值,论证了文中船舶外飘砰击压力设计载荷直接计算方法的合理性。     

楔形与船首外飘剖面的砰击研究

文章通过分析MLM解析砰击模型,提出了一种更适用于大底升角楔形体砰击的半解析砰击模型。通过采用数值仿真技术对外飘剖面入水问题的研究,指出了现有规范方法存在的不足,并扩展了半解析方法来实现外飘剖面砰击压力峰值系数的预报。在楔形剖面与船首外飘剖面的入水砰击研究中,对比了半解析砰击模型和数值仿真技术的计算结果,验证了半解析方法的可行性。     

机载布放式AUV入水冲击仿真研究

机载布放式AUV是利用载机运送至特定海域上空,在一定条件下通过空投方式进入水下,完成预定工作的自主水下航行器。AUV入水时会受到巨大的载荷冲击,严重时会导致机体折断、元器件失灵,甚至引起弹道失控。为此,文章采用计算流体力学(Computational Fluid Dynamics,CFD)方法对机载布放式AUV的入水冲击问题进行了数值仿真研究。对不同入水速度、不同入水角度下AUV受力过程进行了计算,得出了不同入水条件下的速度响应曲线和压力响应曲线,可为机载布放式AUV的机体结构设计和投放条件研究提供参考。     

Evolving Narratives of Low-Carbon Futures in Transportation

Scenarios of low-carbon transport demonstrate that a vast range of different outcomes is possible and contingent on policy, technology and cultural developments. But a closer look indicates that different schools of thought suggest possible pathways diverging in their fine structure. This perspective reveals how three different scientific communities — integrated assessment modelers, transport-sector modelers, and place-based modelers — emphasize distinct solution domains. While integrated assessment models focus on fuel composition, transport-sector models put slightly higher emphasis on efficiency measures; in turn place-based research specifies idiosyncratic behavioral and infrastructural mitigation options that are likely to be beneficial in realizing local co-benefits. These specific local approaches could mitigate urban transport emissions by 20–50%, higher than that revealed in aggregate global models. We discuss differences in approach, possibilities for reconciliation, and the implications of normative assumptions. Targeted three-directional interactions would foster comprehensive understanding of possible low-carbon transportation futures.     

Model for the capacity of the urban signal intersection with work zone

Work zones exist widely on urban arterials in the cities that are undergoing road construction or maintenance. However, the existing studies on arterial work zones are very limited, especially on the work zones at urban intersections, although they have a severe negative impact on the urban traffic system. For the first time, this study focuses on how work zones reduce intersection capacity. A type of widely observed work zone, the straddling work zone that straddles on a road segment and an intersection, is studied. A linear regression model and a multiplicative model suggested by Highway Capacity Manual are proposed respectively to determine the saturation flow rate of the signal intersection with the straddling work zone. The data of 22 straddling work zones are collected and used to evaluate the performances of the proposed models. The results display that the linear regression model outperforms the multiplicative model suggested by Highway Capacity Manual. The study also reveals that reducing approach (or exit) lanes and the mixture of motor vehicles and non‐motor vehicles (and pedestrians) can significantly decrease the capacity of the intersection with straddling work zone. Therefore, in setting a straddling work zone, workers should try to ensure that the intersection approach and exit are unobstructed and set a separation for non‐motors and pedestrians to avoid mixed traffic flow. Copyright © 2016 John Wiley & Sons, Ltd.     

基于影响线的桥梁结构评定理论研究进展

阐述基于影响线的桥梁结构评定理论的研究进展,主要包括5方面内容：1）影响线及其1阶、2阶位置灵敏度分析用于定性判断损伤的存在与否;2）基于影响线的位置敏感性参数对损伤进行定位分析;3）基于影响线的有限元模型修正理论对损伤程度进行定量分析;4）利用影响线评定理论对结构进行评定;5）基于有限元模型修正的损伤函数理论对损伤发展趋势进行预测。这一理论涵盖了损伤评定理论体系的全部内容,为桥梁评定尤其是快速桥梁评定提供了新手段和新思路。