全球LNG船修理格局及2008年修理基本情况

随着世界各国对LNG这种清洁能源的需求日益扩大,作为LNG的运输工具,全球LNG船船队规模获得了前所未有的增长。当今全球LNG船修理中心主要分布在东南亚、中东和西欧三个地区,同时新进入者不断增多,企业间竞争日趋激烈。2008年,全球主要修船企业修理LNG船71艘。     

39 000 dwt 散货船总振动分析

利用NAPA软件强大的编程能力,应用迁移矩阵法开发了用于分析船体总振动固有频率和振型的工具箱。由此自动获取计算总振动所需的几何和工况数据,从而推出了将船体三维建模、装载工况与总振动分析结合起来协同设计新方法,并将此方法成功应用于一艘散货船的总振动分析。     

8 530 TEU集装箱船全船弯扭强度和舱口角疲劳强度分析

8 530 TEU集装箱船的船长和船舱大开口宽度都显著超过国内船厂以往建造的集装箱船,因此对该船的波浪诱导载荷、全船弯扭强度,以及舱口角的疲劳强度都作了认真研究。研究中建立全船有限元模型,用来分析波浪诱导载荷,计算船体结构应力水平等。在此基础上,选取3个典型的舱口角,建立精细有限元模型,利用热点应力法,计算舱口角热点应力范围和热点疲劳寿命。最后总结出该集装箱船的全船弯扭强度和舱口角疲劳强度的特点。     

自由站立式立管总体设计与分析

介绍自由站立式立管(FSHR)系统中各构件设计原则及其总体响应分析方法,根据算例总体设计参数,建立FSHR总体有限元模型,进行总体强度与疲劳分析.计算结果表明,其设计参数在各种工况下均满足强度要求,其中百年一遇海流载荷工况为最危险工况;其设计参数满足疲劳要求,运动疲劳和VIV疲劳最大损伤均出现在刚性主管顶部.     

全船有限元简化方法在总纵强度计算中的应用

采用全船有限元总强度计算的简化方法,阐述了具有长上层建筑、大开口、全通甲板的船舶在垂向弯矩作用下的总强度应力分布情况,提出了非常规结构船舶总强度计算方法,分析了上层建筑参与总强度的有效度。对有效避免波浪载荷及平衡力计算带来的总强度计算误差和庞大的计算工作量,缩短计算周期以及优化结构等提供指导。     

欠驱动船舶全局K指数航迹跟踪的级联反步法

研究一类欠驱动船舶的全局航迹跟踪问题。首先对船舶动态系统和期望动态系统分别进行全局微分同胚变换,得到航迹跟踪的误差动态方程,由此将航迹跟踪问题转化为误差动态系统的镇定问题,然后利用级联系统理论将误差动态方程的镇定问题分解为两个独立子系统的镇定问题。通过分别为子系统设计全局指数稳定控制律实现了欠驱动船舶的全局K指数航迹跟踪。仿真结果验证了所提方法的有效性。     

Dynamic response of a surface ship structure subjected to an underwater explosion bubble

Bubble load in a noncontact underwater explosion can cause the ship hull global response and local response. In current literature, the ship hull is usually simplified as a hull girder to analyze its global response. However, literature dealt with the local response of a 3-D surface ship hull subjected to an underwater bubble were limited. This investigation develops a procedure which couples the finite element method with doubly asymptotic approximation (DAA) method to study the problem of transient responses of a ship hull structure subjected to an underwater explosion bubble. Using a 3-D ship model as examples, the global and local responses of the ship model in vertical, transverse and longitudinal directions are performed in detail. The acceleration, velocity and displacement time histories are presented. The characteristics of both the global and local responses of the ship model are discussed. The numerical results show that besides global whipping response, the ship hull also sustains severe local responses in different directions subjected to underwater explosion bubble jetting, which should be taken into consideration.     

Fuzzy empty containers excess estimation as an economic indicator—the case of the north Adriatic port system

Today, approximately 90% of the world’s cargo is moved by ships and almost all general cargoes are transported in containers. Worldwide container traffic has increased over the last 20 years by 7% annually, and containerization has begun to seriously impact global trade patterns. As a result, container terminals have become very important nodes in the world’s supply chain. In this article, we have highlighted the link between the total and empty container traffic and the global economy. By way of example, we have analysed the empty container traffic in north Adriatic ports in the years before and during the global economic crisis and in a period of stability after the major economic slump. We used a fuzzy multicriteria algorithm to find out how the global crisis, which has affected ports, influences the number of excess empty containers at the terminals. We show that these factors, in particular the change of the global financial and economic situation, have different repercussions to the ports of the north Adriatic: less serious effects upon the ports that are well connected locally and substantial consequences for the ports that are well connected globally.     

一种混合优化的全局路径规划算法

针对全局路径规划研究中遗传算法存在搜索范围广而导致收敛速度慢的问题,本文提出一种混合优化的全局路径规划方法,完成对图像读取、处理后使用A*算法预处理缩小可行区域从而提高收敛速度。所提出的混合优化规划方法主要优化遗传算法的初始种群,在不影响最终路线的情况下,缩小初始种群的搜索范围,提高算法进行全局路径规划的速度,快速有效的规划出全局路线。另外本文给出一种评价体系对规划结果进行定量的避障评价,评价结果能够以数值形式对规划结果进行综合评价,评价结果显示通过混合优化算法规划出的路径具有更佳的安全性。     

60客位海景观光船结构强度计算和校核

由于工作于水下,水下观光船大量使用钢化玻璃结构,使船体强度的校核很难用常规规范的方法或舱段有限元方法,为此,运用有限元分析软件MSC.Patran/Nastran对60客位海景观光船进行全船有限元建模,根据规范计算波浪和运动载荷,对模型进行加载,计算得到全船包括钢化玻璃结构在内的应力分布和相对变形情况.     

基于粒子群优化的聚类入侵检测算法

为了在入侵检测中有效地克服传统的K均值算法易陷入局部极小值的缺点,使算法具有较好的全局收敛性,将粒子群优化算法应用于入侵检测,给出了基于粒子群优化的K均值聚类算法．通过理论分析及实验,验证了基于粒子群优化K均值聚类算法的有效性．对KDD CUP99数据集仿真,实验结果表明,该算法在入侵检测中能获得理想的检测率和误检率．     

薄膜型LNG船全船结构屈服和疲劳强度分析

以某薄膜型液化天然气（Liquefied Natural Gas,LNG）船的结构设计为例,开展全船屈服强度校核和基于精细网格的有限元疲劳强度分析。针对5种典型装载状态,基于美国船级社（American Bureau of Shipping,ABS）全船强度直接计算指南,采用ABS-DLA/SFA系列软件,用三维波浪载荷预报程序对波浪随机载荷进行长期预报。基于预报结果,针对每种装载状态计算15个设计波参数组,求解全船结构在各载荷组合工况下的应力分布,继而完成屈服强度校核。以甲板机械室与穹顶甲板相交处的关键节点区域的节点设计为例开展细网格局部强度分析,并通过各种改进设计解决应力集中问题。针对2种常用典型操作装载状态及营运于北大西洋海区疲劳寿命满足40a的要求,基于ABS全船疲劳强度直接计算指南计算2个典型细化位置热点应力传递函数,通过谱分析得到疲劳累积损伤和疲劳寿命,完成疲劳强度校核。采用的全船强度和疲劳分析方法和思路适用于其他超大型船舶的结构分析。     

全球典型中转港发展格局、特征及趋势研究

全球海运的发展催生出以转运货物形式服务于周边区域和远洋运输的中转港,它们在全球贸易及运输体系中占据重要地位,形成了明显的特征格局。在中转港形成因素及分类研究的基础上,总结全球范围中转港发展格局和发展特征,探讨不同区域中转港的发展趋势。结果表明,当前全球航运格局重心在亚太地区,国际中转港主要分布在远东-西欧-北美主航线,而扼守关键区位则容易催生出中转大港。同时,未来各区域的中转港发展将随着经济全球化与国际贸易的深入发展而变动,并受船舶大型化、服务软环境等显著影响。     

Connectivity analysis of the global shipping network by eigenvalue decomposition

ABSTRACT

Maritime shipping necessitates flexible and cost-effective port access worldwide through the global shipping network. This paper presents an efficient method to identify major port communities, and analyses the network connectivity of the global shipping network based on community structure. The global shipping network is represented by a signless Laplacian matrix which can be decomposed to generate its eigenvectors and corresponding eigenvalues. The largest gaps between the eigenvalues were then used to determine the optimal number of communities within the network. The eigenvalue decomposition method offers the advantage of detecting port communities without relying on a priori assumption about the number of communities and the size of each community. By applying this method to a dataset collected from seven world leading liner shipping companies, we found that the ports are clustered into three communities in the global container shipping network, which is consistent with the major container trade routes. The sparse linkages between port communities indicate where access is relatively poor.     

Global warming and severe weather activity

The concentration of atmospheric CO₂ has been significantly increasing mainly due to human consumption of fossil fuels since the middle of the 18th century. Although the recent increases of CO₂ could possibly give rise to some warming, serious problems remain unresolved in relation to the concept of global warming. The focus of this paper is directed at two areas: the first is the credibility of the global warming prediction, and the second is the long-term trend in severe weather activity associated with global warming. The global warming during the last century has been confirmed by observational data. The magnitude of the warming averaged globally is about 0.6°C during the last century, and is consistent with the computed increase in CO₂ concentration. The observational data indicate a large degree of hemispheric asymmetry; the warming of the Northern Hemisphere is slower and sometimes temporarily interrupted comparing with that of Southern Hemisphere. It is an open question why this hemispherical asymmetry is of opposite sense to the results of numerical simulations for the increases in CO₂ concentration. This question may possibly be resolved by consideration of the climatic effects of increases in anthropogenic aerosol levels in the troposphere in addition to greenhouse gas effects. One question raised by global warming is whether the frequency and intensity of extreme weather events have shown a long-term increased in association with global warming. Since extreme weather such as torrential rainfall and tropical cyclones are relatively small-scale, short-lived phenomena, they cannot be successfully simulated using general circulation models (GCM) at the present time. Furthermore, the limited period of the available observational data makes it difficult to produce any meaningful results with conventional statistical methods. A new statistical method, which was proposed by the present author and a colleague, is applied to the maximum daily precipitation data, and significant evidence is found for an interdecadal increasing trend in the intensity of extremely heavy rainfall. It is argued that the most likely cause of this trend is global warming. With regard to the relation between global warming and tropical cyclone activity, no significant results have yet been obtained either by numerical simulation or statistical analysis of historical data. Recent research analyzing historical data on the relation between tropical cyclone intensity and sea surface temperature has emphasized that the warmer sea surface accompanied by global warming could increase the maximum possible intensity of cyclones, although no appreciable change would be seen in the average intensity of regular storms. Presented at the International Conference on Technologies for Marine Environment Preservation (MARIENV’95), Tokyo, Japan, September 24–29, 1995.     

集束塔式立管总体疲劳分析方法研究

考虑到集束塔式立管比单根塔式立管在总体疲劳分析时更加复杂,利用＂等效＂理论方法对集束塔式立管进行处理,建立集束塔式立管有限元模型,提出集束塔式立管总体疲劳（包括运动疲劳和VIV疲劳）的分析方法,并通过实际的案例给出相关计算结果,证明该方法是正确和合理性的。     

Spatial pattern of the global shipping network and its hub-and-spoke system

Port system is a research focus of transport geography, and most studies believe carriers are important factors in the development and concentration of the port system. Since the 1990s, carriers have played an important role in organizing the global shipping network and reorganizing the port system. But there isn’t a perfect method to evaluate carriers’ influence and the roles of each port in the maritime shipping networks. In this paper, we use the monthly schedule table of international carriers to describe and model the spatial pattern of the global shipping network and identify its hub-and-spoke system. The result shows that a hierarchical structure exists in the global shipping network. The North Hemisphere, especially the East Asia and the Southeast Asia, is a dominant region of the worldwide shipping network. East Asia, Southeast Asia, Northeast Europe, and East coast of the USA are the concentration regions of worldwide shipping lines. The ports of Hong Kong, Singapore, Shenzhen, Shanghai, and Kaohsiung etc have advanced capacity for maritime shipping and high potentials for being hub ports in the global shipping network. Today, the worldwide shipping network is transforming from the multi-port calling system to 44 regional hub-and-spoke systems. Meanwhile, the sub-networks with hub ports of Antwerp, Singapore, and Hong Kong have become the most important ones and dominate the whole global shipping network.     

水下传感器网络覆盖优化算法

针对水下传感器网络随机部署时节点分布不均匀、网络覆盖率不高问题,提出一种基于改进全局人工鱼群算法的网络覆盖优化算法。优化算法以覆盖率为目标函数自适应调整人工鱼移动步长,同时在向最优人工鱼靠拢过程中引入权重系数,提高算法寻优精度和收敛速度。实验结果表明,与遗传算法和鱼群算法相比较,该改进算法优化了网络覆盖率,加快了算法收敛速度,提升了网络性能。     

深水半潜式钻井平台总体强度分析及冰载荷下结构评估

本文主要概述了某深水半潜式钻井平台的特点,按照DNV的相关规范,采用了有限元法和设计波法,建立了总体有限元模型,分析了在风暴自存工况下的总体屈服强度和屈曲强度,并进行了冰载荷作用下的结构评估。可得到结论,总体屈服强度和屈曲强度是满足的。本文可以为以后同类平台的总体强度分析提供借鉴。     

全球供应链视角的东亚港口物流服务绩效与趋势分析*

东亚港口基于旺盛的贸易运输需求而在全球供应链体系中崛起,同时也因为港口拥挤等问题而存在降低贸易成本的空间。首先从全球供应链视角解析港口物流服务格局,突出了东亚地区、特别是中国港口的地位,评价港口物流的综合绩效和竞争状态,然后对发展趋势做出预测。研究发现：东亚港口将通过持续投资实现供给需求的动态平衡;日本地震引致的全球供应链重组将使港口物流服务发生结构性变化,东亚将加强跨国港口物流合作以满足区域经济一体化的要求。