固定式海洋平台的时域振动响应研究

近海结构的研究是海洋工程领域的重要专题。本文以Airy线性波理论和莫里森方程为基础推导平台结构的运动方程。将波浪力简化为二节点集中载荷,从动力学的角度分析结构的响应特征。以一简化的固定平台为算例,以不同的入射波为激励条件分析比较结构的位移响应、速度响应以及加速度响应。研究结果表明,随着入射波强度的增大,结构的振动变得更为剧烈,且结构的振动响应不仅与入射波的周期和波高有关,与波浪的形式也有一定的关系。     

波浪冲击作用下海洋结构物的动力响应

通过对海洋结构物在波浪冲击作用下动力响应的试验研究,分析了波浪冲击作用下结构物最大动力响应及出现的时间。基于Fourier变换的频谱分析,得到了波浪冲击荷载作用下平台结构的水平和竖向振动特性。当入射波频率接近平台水平固有频率时,在水平方向会产生共振。结构物模型竖向刚度较大,试验中竖向不发生共振。     

畸形波作用下张力腿平台的瞬时响应

应用Tromas等(1991)提出的新波理论的概念,建立了极限入射波浪模型,并把该模型引入到极限波浪与平台互相作用的水动力计算中.研究中应用大连理工大学海岸及近海工程实验室开发的频域波浪力分析程序WAFDUT1.4,得到结构的波浪力传递函数和水动力系数.通过平台运动方程在时域内计算得到运动响应和张力腿受力.最后,进一步研究了张力腿平台的刚度系数和波浪周期的改变对张力腿平台的运动响应和张力腿受力的影响.     

半潜式钻井平台波浪散射力与运动响应分析

文章对半潜式钻井平台(Semi-Submersible)在波浪作用下的散射波浪力和运动响应进行了分析研究,研究中采用了基于波浪辐射、绕射理论的三维有限水深格林函数方法.为了保证这种大型复杂海工结构物计算结果的高精度,研究中对于边界积分方程的离散求解采用了考虑几何对称性的高阶边界元算法.通过对计算结果的比较分析,对这种型式的钻井平台的波浪力和运动响应有了一个全面的认识,对结构设计有很好的参考价值.     

波浪冲洗对多浮冰耦合运动影响特性研究

冰缘区是开阔水域与海冰的交界区域,波浪与海冰的相互作用是决定该区域形态结构的主要因素.本文基于计算流体力学技术,采用速度入口造波方式建立二维数值波浪水池,利用动网格技术模拟多浮冰的耦合运动,在典型入射波参数范围内,研究了波浪中浮冰的垂荡和纵摇响应.同时,重点探究了波浪冲洗冰体表面现象,及其对浮冰耦合运动的影响,对比分析了有/无波浪冲洗冰体表面时的浮冰运动响应.数值结果表明:低密集度浮冰更容易产生波浪冲洗现象,且波浪冲洗对浮冰运动具有较明显的抑制作用.     

海底管跨涡激振动疲劳可靠性研究

本文考虑波浪水质点与管线振动间的相对运动速度以及波浪和海流的联合作用,对传统的波浪载荷计算方法进行了改进,引入了波浪激励载荷中的二阶平方阻尼项,从而建立了管跨段的非线性涡激振动方程.通过较为合理的化简,将非线性随机振动方程化为相应的线性随机振动方程.利用谱分析解法,由波浪谱推得海底管线的波浪力谱,作为振动方程的输入谱,计算得到相应的输出谱,进而确定位移和应变等各种响应随机过程的概率分布,最后结合可靠性分析理论确定管线的疲劳失效概率.     

基于极点配置的海洋平台粘弹性阻尼振动控制

对随机波浪激励的多自由度海洋平台模型进行动力分析,研究基于粘弹性阻尼器的海洋平台振动控制及阻尼器的位置优化,提出使用极点配置技术实现粘弹性阻尼器的优化定位;粘弹性阻尼器采用开尔文模型,将其对结构的作用看作是位移和速度的反馈控制.针对一海洋平台计算模型,在随机波浪载荷作用下进行平台振动响应分析及阻尼器的位置优化设计,结果表明采用极点配置技术设置粘弹性阻尼器,平台位移和加速度响应得到有效控制.     

自升式平台的自由振动计算方法研究

采用直接简化计算方法和三维有限元方法对某400 ft平台进行一阶自由振动频率的计算。两种方法均对泥面下3 m作简支处理,因三维有限元方法需较为准确地体现平台质量分布,所以直接简化计算方法在前期设计阶段表现的较为方便和有效。为工程设计者们在自升式平台自由振动的研究前期设计阶段确定波浪载荷对平台的动态响应影响提供依据和参考。     

船舶响应波浪激励的时域水弹性理论

本文提出了浮体与入射波之间汉体－结构相互作用的时域线性理论。在讨论中假设结构是弹性的，并用广义的分离变数法来描述，而流体则被描为有势的自由表面流的初始边界值问题。在描述可变形结构附近流体运动的数学公式中采用了广义界面边界条件。为了分析波浪诱导的单体船总体响应，将时域理论简化为细长体理论。     

波浪荷载作用下海洋平台半主动控制试验研究

为研究半主动控制方法对波浪荷载引起海洋平台振动控制的效果及特点,以一典型导管架式海洋平台为原型,根据动力相似准则按1∶50比例设计海洋平台结构模型,以磁流变阻尼器为半主动控制实现装置,优化设计半主动控制系统.在此基础上进行了规则波和不规则波2种工况下波浪水池模型试验,对平台在波浪荷载作用下的减振效果进行了研究.试验结果表明:磁流变阻尼器半主动控制系统能够对平台结构的振动进行有效地控制,且控制效果较稳定.     

Errata

正In the paper"Influence of Fouling Assemblage on the Corrosion Behaviour of Mild Steel in the Coastal Waters of The Gulf of Mannar,India"in Vol.12,No.4,Page:509,References were lost,and the two authors’biographies were identical.The correct text is shown below.We apologize to the authors and our readers for any inconvenience caused by the errors.     

Journal of Marine Science and Application 2014 Sum. Contents

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第34届海洋、离岸及极地工程国际会议(英文)

正St.John's,Newfoundland,Canada,May 31-June 5,2015 OMAE2015 is the ideal forum for researchers,engineers,managers,technicians and students from the scientific and industrial communities from around the world to: meet and present advances in technology and its scientific support;     

33rd International Conference on Ocean,Offshore and Arctic Engineering （OMAE2014）

正San Francisco,California,June 8-13,2014.OMAE 2014 is the ideal forum for researchers,engineers,managers,technicians and students from the scientific and industrial communities from around the world to:·meet and present advances in technology and its scientific support;·to exchange ideas and experiences whilst promoting technological progress and its application in industry·to promote international cooperation in ocean,offshore and arctic engineering.In line with the tradition of excellence of previous OMAE conferences,more than 900 technical papers are planned for presentation.Outreach for Engineers Specialty Forum This Specialty Forum is designed for students and professionals who may not be familiar with the Ocean and Offshore industry,as well as those who have just recently specialized in this field.     

联合作战计划和执行系统

全球指挥控制系统(GCCS)实施当前美国海军网络中心战信息基础设施的联合计划网络。联合作战计划和执行系统(JOPES)支持GCCS实现联合计划。JOPES有两类计划：时间不限的精密预案计划生成作战计划、方案计划或职能计划；时间敏感的危机行动计划生成作战命令或战役方案。前者在和平时期创建的作战计划是后者的计划基础，加速应付危机的能力。     

Recent progress on wave induced loading measurements in warships

Recent measurements of wave induced hull strain and flexure in RN warships are presented together with the derivation of the current design criteria for extreme hull girder bending loads. The history of the development of the shipboard instrumentation used is given and recent developments to improve the quality and ease of analysis of the data are described. An unexpectedly high transverse asymmetry in the longitudinal strains measured in destroyers is shown to be the result of a combination of vertical and lateral bending in oblique seas. Finally recent theoretical comparisons between the loading of Deep-Vee hulls and conventional UK rounded bilge hulls are presented which demonstrate the higher loading experienced by this type of hull form.     

The 11th International Conference on Hydrodynamics (ICHD 2014)

正19–24 October 2014 SingaporeCONFERENCE THEMES The overall aim of the ICHD Conference is to provide a forum for participants from around the world to review,discuss and present the latest developments in the broad discipline of hydrodynamics and fluid mechanics.The first International Conference on Hydrodynamics(ICHD)was initiated in 1994 in Wuxi,China.Since then,9 more ICHD conferences were held subsequently in Hong Kong,Seoul,Yokohama,Tainan,Perth,Ischia,Nantes,Shanghai and St Petersburg.Evidently the ICHD conference has become an important event among academics,researchers,engineers and operators,working in the fields closely related to the science and technology of hydrodynamics.The 11th ICHD will be held in Singapore in 2014.     

第十二届深水操作会议和展览会(英文)

正November 4-6,2014Moody Gardens HotelConvention Center/Galveston,TX The Deepwater Operations Conference and Exhibition is celebrating its 12th anniversary this year.This growing event will continue the tradition of excellence in addressing operational challenges involved in developing deepwater resources.We will return to the Moody Gardens Hotel and Convention Center on November 5-7,2014 in Galveston,Texas.     

Eastbound or westbound ?

In terms of equal sailing distances, where is the inflexion when ships depart from ports in the Asian Continent to New York via Suez and/or Panama？
The answer is China South Port Group （Hong Kong, Shenzhen and Guangzhou）.     

Impact of regulation on the performances of long-distance transport services: A comparison of the different approaches in Sweden and Norway

Despite the many socio-economic similarities between Sweden and Norway, differences in jurisdiction, organisation, cooperation, and financing of long-distance passenger train and coach services have led to the development of four distinctively different ways of serving the markets. This paper describes how the train and coach markets have developed in the two countries, with emphasis on regulatory and industrial structure and a couple of performance variables.Looking at passenger rail, both countries separated infrastructure from operation over a decade ago. However, while Norwegian rail is characterised by an almost monopoly supplier, rail services in Sweden are partly decentralised to the responsibility of county authorities and are widely subjected to competitive tendering. The rest of the network is about to be opened up for on-the-track competition. Swedish Rail (SJ) has spent the last decades consolidating its core business (passenger rail) and sold out its other businesses. In contrast, the Norwegian state rail (NSB) has expanded its business to become a major bus operator and property owner, with extensions also into the Swedish market.The coach industry was more recently deregulated in both countries. The Swedish coach market is dominated by privately owned companies operating services to and from Stockholm. In Norway, state-owned NSB is a major coach operator on medium distance routes, and is also the largest partner of Nor-Way Bussekspress which totally dominates long-distance coach services. Further, the Norwegian coach market is characterised by cross-ownership and cooperation which has enabled an extensive route network which covers most of Norway.We find distinct differences in achievements in the two modes and in the two countries. Swedish rail services have succeeded in winning market shares and in renewing and developing both infrastructure and service levels to a greater extent than the Norwegian model. On the other hand, the Norwegian coach market seems to be more developed and efficient compared to its Swedish counterpart.The paper concludes with a discussion on the possible links between the different approaches and the performance observed, with the aim to stimulate further and more detailed research on some important issues.