一种基于APDL语言的船舶波浪压力自动加载方法

针对全船结构强度直接计算中,波浪加载较为麻烦的问题,提出了一种ANSYS环境下的波浪压力自动加载的方法。该方法将三维水动力程序计算的船体表面的波浪压力经过插值算法转换到有限元结构单元上,压力数据文件读入ANSYS实现了自动加载。最后,利用该自动加载方法对一艘穿浪双体船进行加载。结果表明,该方法将波浪载荷计算和结构强度分...     

波浪对船舶轴系的影响

考虑到波浪易造成大尺度柔性船体变形,进而对轴系造成较大影响,基于PCL语言对船舶有限元模型编制智能划分水线处单元及高效计算、加载波浪力的程序,对某大型散货船有限元模型加载Ariy波浪压力,计算分析波浪力在不同迎浪角度及不同相位对船舶轴系的影响。     

基于PCL语言的波浪压力自动加载方法

提出了一种基于PCL(Patran command language)语言的波浪压力自动加载方法.其基本思想是,将单元分为完全在水线以下以及横跨水线的两种类型,第一类单元在加载时直接施加单元压力,对于第二种类型的单元,考虑了部分受压的影响,将四边形单元转化为三角形单元,得到了单元节点力.并对加载的具体实施过程及相关的PCL函数进行了较为详细的说明.最后,利用该自动加载方法对滚装船进行了加载.结果表明,文中的自动加载方法将压力计算与压力施加有机地联系了起来,有效地解决了加载的效率的问题,不仅缩短了加载数据的时间,而且避免了数据录入错误的发生,为有关人员对结构物进行强度有限元分析时进行载荷施加提供了自动化的方法.     

基于水动力—结构模型的VLGC强度和疲劳分析

超大型全冷式液化气船（VLGC）是国际上公认的设计及建造技术难度最大的船型之一,VLGC波浪载荷是船舶设计计算分析的重要载荷,准确的评估波浪载荷对船舶强度的设计非常重要。论文从DNV先进的水动力计算软件HydroD对VLGC船满载和压载工况下的波浪载荷进行了计算,得到了VLGC船相应工况下的运动响应和短期预报、长期预报值,并把计算出的波浪载荷传递到全船结构有限元结构模型中,加载分析得到了VLGC船的应力分布,对相应地方做了适当改进和加强,并对典型节点进行疲劳强度分析,得到了典型节点的疲劳寿命。对VLGC船整个波浪载荷传递到有限元模型的这一套流程做了分析和研究,也为进一步应用水动力方法计算其它船型的结构强度和疲劳寿命打下了良好的基础。     

波浪作用下弹性海床孔隙水应力响应的数值模拟

基于二维动力Biot固结理论,描述了海床土骨架的应力、应变和时间的本构关系,从Galerkin加权余量法出发建立了以土骨架位移u和孔隙水压力p表达的u-p形式的有限元方程,并采Wilson-θ直接数值积分法求解时域内动力方程。数值计算结果表明,在波浪作用下,海床孔隙水压力的计算值与实测值基本吻合,用文中的理论计算模型描述沙床对波浪荷载的响应是可靠的。     

集装箱船在波浪下的结构动态崩溃数值仿真研究

船舶遭遇大波浪载荷后极可能产生结构崩溃事故,集装箱船具有甲板大开口,在大波浪下更容易产生结构动态崩溃.文章提出一种联合三维势流理论和非线性有限元的数值仿真方法用于计算集装箱船在波浪下的结构崩溃响应,采用势流理论计算船体的波浪载荷,采用非线性有限元计法计算结构的崩溃响应,实现波浪载荷由水动力模型至有限元模型的映射,以典型...     

基于设计波法的舰船整船有限元强度分析

基于谱分析法对舰船剖面波浪载荷进行长期预报并确定设计波参数.利用有限元软件MSC.Patran 建立了全船有限元模型,通过PCL语言实现设计波波浪压力对船体湿表面有限元网格的自动加载.对2个设计波下的整船有限元进行分析,结果表明:整船分析不仅能真实表现舰船整体总纵变形和应力水平,还能充分考虑局部载荷对结构响应的影响.另外,基于三维水动力理论分析船体运动和剖面载荷进而确定设计波参数的过程,克服了传统经验公式估算载荷所导致的结果的不确定性和强度校核的不合理性.     

浅水超大型FPSO脉动压力研究

随着浅水超大型FPSO在渤海湾海域的广泛应用,水深对波浪诱导载荷的影响成为新的热点课题.文章推导了有限水深复合格林函数,结合三维势流理论用于计算浅水FPSO的水动力特性.采用开发的程序计算了一艘浅水300KDWT FPSO的脉动压力.计算结果表明浅水脉动压力与深水脉动压力的分布规律明显不同.     

随机波浪作用下砂质海床中的孔隙水压力响应

本文以动弹性固结理论和线性渗流理论为基础，建立了求解随机波浪作用下饱和砂质海床中孔隙水压力响应的有限元方程，并用Wilson-θ法进行动力响应求解。海床可为具有任何边界条件的分层分块介质，作用波浪可为任何形态的随机波浪。忽略波浪和海床的动态相互作用，海床面上的波浪压力可先按各种波浪理论进行计算，之后作为边界塔荷载作用于海床。计算孔隙水压力与模型实验的量测值吻合较好。通过计算讨论分析了砂质海床中的孔隙水压力响应。     

基于谱分析法的船舶结构疲劳强度评估

本文采用基于谱分析法的直接计算法对某船舶结构进行疲劳强度评估。基于三维势流理论与北大西洋海况对该船舶进行水动力分析,得到了满载巡航工况下的波浪压力分布和舱段端面的水平弯矩、垂直弯矩、横向扭矩。同时根据船舶具体结构形式和数值计算的可行性对船体结构进行适当简化,并选用合适类型的单元对船舶结构进行离散,从而得到了船舶三舱段有限元模型。将波浪压力、惯性力、端面弯矩等载荷施加到舱段有限元模型上,得到了典型热应力点的疲劳强度应力值,然后通过谱分析法估算出疲劳寿命。研究结果可为该船舶初步设计阶段的结构优化提供有益参考和借鉴。     

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;     

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。     

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）.     

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.     

桥梁防撞设施物理模型试验

物理模型试验是预报防撞设施所受撞击力及优化设计方案的主要方法之一。结合杭州湾大桥柔性防撞设施及东海大桥独立式防撞体设计方案,阐述了船—防撞体撞击试验的基本原理、方法、试验方案及相关试验结果。提出了柔性防撞系统的优化方案。试验结果表明,该方案经济有效,可供预报类似桥梁防撞设施撞击力时参考。     

印尼某电厂码头水工建筑物设计

印尼某电厂项目码头水工建筑物包括码头、防波堤和护岸等主要组成部分。在该项目水工建筑物的设计过程中,综合考虑当地的自然条件、施工能力和材料来源等因素,不断优化结构选型和结构断面。根据不同使用要求,护岸分别采用直立式和斜坡式2种结构型式,推荐的设计方案节省投资、施工方便,可供同类工程设计参考。     

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.     

开放式数据挖掘系统模型

目前国内已经出现了少量的数据挖掘相关产品。国内数据挖掘软件无论从数量还是质量上比较，都与国外软件存在着较大的差距。随着数据仓库技术的普及，数据挖掘应用的需求越来越强烈，如何缩短这种差距，研发数据挖掘软件产品成为国内业界的一个重要问题。通过引用目前国际通用数据挖掘标准技术来构建开放式的数据挖掘系统模型，该系统模型从可扩展性、可重用性、易用性等方面得到了加强。