Finite Element Analysis of Deformed Legs of Offshore Platform Structures     

LIU  Chuntu 《中国海洋工程》2002,16(3):311-320

The element stiffness matrix of the equivalent beam or pipe element of the deformed leg of the platform is derived by the finite element method. The stresses and displacements of some damaged components are calculated, and the numeri-cal solutions agree well with those obtained by the fine mesh finite element method. Finally, as an application of this method, the stresses of some platform structures are calculated and analyzed.  相似文献   

Human activities in UK offshore waters: an assessment of direct, physical pressure on the seabed   总被引：1，自引：0，他引：1  

Eastwood  P. D.; Mills  C. M.; Aldridge  J. N.; Houghton  C. A.; Rogers  S. I. 《ICES Journal of Marine Science》2007,64(3):453-463

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MATLAB在海底管线阴极保护电场计算中的应用          下载免费PDF全文

胡舸  向斌  张胜涛 《海洋科学》2007,31(12):34-37

海洋钢结构阴极保护电场的数值模拟仿真和计算是当前海洋腐蚀、阴极保护研究和工程实践中一个重要的研究方向。研究海底管线的腐蚀状态就必须准确测定管线表面的电位分布,而实际测量中深海管线表面电位分布难以直接测量。构建了海水中钢管线的阴极保护数学模型,采用以边界元法为基础的数值计算方法,利用Matlab开发了均匀电解质中电位分布的计算软件,实测中通过对腐蚀电场海水区域环境电场的测量,就可实现不接触测量管线表面电位的目的。最后通过海洋实测验证了计算结果的可靠性,证明了基于Matlab的数值仿真计算引入阴极保护设计中是行之有效的。  相似文献   

Fouling in offshore areas southeast of the Zhujiang (Pearl) River Delta, the northern South China Sea     

Yan Tao  Yan Wenxi  Dong Yu  Liang Guanhe  Yan Yan  Wang Huajie 《海洋学报(英文版)》2003,22(2):201-211

Abstract-In order to understand the type and extent of marine fouling in offshore areas southeast ofthe Zhujiang (Pearl) River delta, within the period form May 1986 to June 1987, two biologicalbuoys were deployed at water depths of 95 m and 113 m located in 114 km and 160 km off the coast ofHong Kong, respectively. Moreover, the fouling community of a Marex hydrological buoy located in115 m depth water 172 km off Hong Kong was also surveyed. The results show that a total of 78species were collected and identified. The panels exposed for 3 months were mainly dominated bystalked barnacles Conchoderma hunteri and Lepas anatifera and hydroids Orthopyxis sp. As for thebuoys, including the subsurface buoy, and their mooring systems exposed for 6 and 12 months, respec-tively, some hard foulers such as common oysters, pearl oysters, acorn barnacles and bryozoans werealso found. The compositions of fouling communities also varied greatly with depth.  相似文献   

Assessment of Fatigue Strength of An Offshore Floating Production and Storage Unit     

LIU  Jiancheng 《中国海洋工程》2002,16(1):41-49

The procedure of assessment of structural fatigue strength of an offshore floating production and storage and offloading unit(FPSO) in this paper. The emphasis is placed on the long-term prediction of wave induced loading, the refined finite element model for hot spot stress calculation, the combination of stress components, and fatigue damage assessment based on S-N curve.  相似文献   

质心分析法在小沙洲动态演化分析中的应用--以江苏辐射沙洲亮月沙为例     

刘永学  张忍顺  李满春 《海洋通报》2004,23(1):69-75

在遥感(RS)、GIS技术的支持下，根据1973—2000年江苏盐城幅卫片，对江苏辐射沙洲外围小沙洲的动态趋势研究方法进行了探讨。在小沙洲轮廓边缘叠合比较的基础上。引入了形态学中质心的概念，并将之运用到辐射沙洲北部的亮月沙沙洲中。研究结果表明：(1)通过对外围小沙洲进行质心分析，可较好地揭示小沙洲的动态变化趋势。(2）亮月沙在整体南退的趋势下，同时还叠加了较为明显的东西摆动韵律，共可分为6个阶段。本文还对亮月沙动态变化趋势原因进行了讨论。  相似文献   

传感器优化配置的修正逐步累积法   总被引：1，自引：0，他引：1  

刘娟  黄维平 《中国海洋大学学报(自然科学版)》2003,33(3):476-482

讨论了模态实验中传感器的配置问题。利用结构振型矩阵转置的 QR分解得到传感器的初始配置。以模态置信度 MAC矩阵的最大非对角元为目标函数 ,利用本文提出的修正逐步累积法得到传感器的配置 ,并提出传感器配置必须结合优化效果和经济性 2方面综合考虑  相似文献   

加拿大海洋调查设备与方法     

杨金玉  张志珣 《海洋地质前沿》2003,19(1):5-8

总结了加拿大地调局在开展近海陆坡及大陆架地质、地球物理调查和其他综合海洋调查工作时通常使用的专门的调查仪器和设备，包括调查船、定位系统、测深设备、侧扫声纳设备、取样取心设备、地震调查设备、水下摄影设备及其他设备以及相关的调查技术；总结了我们在海洋地质调查方面与加拿大的差距。  相似文献   

Dating of Dissolved Iodine in Pore Waters from the Gas Hydrate Occurrence Offshore Shimokita Peninsula,Japan: 129I Results from the D/V Chikyu Shakedown Cruise     

Hitoshi Tomaru  Udo Fehn  Zunli Lu  Rika Takeuchi  Fumio Inagaki  Hiroyuki Imachi  Ryosuke Kotani  Ryo Matsumoto  Kan Aoike 《Resource Geology》2009,59(4):359-373

Iodine concentration and radioisotopic composition (¹²⁹I/I) were measured in the pore waters from the gas hydrate occurrence in the forearc basin offshore Shimokita Peninsula, north-eastern Japan, to determine the source formation of I and accompanying hydrocarbons. Iodine concentrations correlate well with the alkalinity and SO₄ patterns, reflecting degradation stages of I-rich buried organic matter, rapidly increasing in the sulfate reduction interval, and becoming constant below 250 meters below the seafloor with an upwelling flux of 1.5 × 10⁻¹¹ µmol cm⁻² year⁻¹. The ¹²⁹I/I ratios of 300 × 10⁻¹⁵–400 × 10⁻¹⁵ in deep pore waters suggest ages for iodine and hydrocarbon sources as old as 40 Ma. These ages correlate well with the coaly source formations of the Eocene age thought to be responsible for the conventional natural gas deposits underlying the gas hydrate stability zone. Similar profiles are observed in ¹²⁹I/I ratios of pore waters in the gas hydrate stability zone from the forearc basin in the eastern Nankai Trough, offshore central Japan, where pore waters are enriched in I and reach ages as old as ∼50 Ma through the sediment column. At the outer ridge site along the trough, on the other hand, relatively younger I are more frequently delivered probably through thrusts/faults associated with subduction. The nature of source formations of I and hydrocarbons in the offshore Shimokita Peninsula has a more terrestrial contribution compared with those in the Nankai Trough, but these formations are also considerably older than the host sediments, suggesting long-term transport of I and hydrocarbons for the accumulation of gas hydrates in both locations.  相似文献   

中国东部海区科学钻探工程CSDP-02井钻探效率统计分析          下载免费PDF全文

翟育峰  张英传  田志超 《探矿工程》2019,46(12):13-17

CSDP-02井是中国东部海区科学钻探工程2井,该井采用五开结构,完井井径98 mm,完井井深2843.18 m,历时504 d,创造了海洋科学钻探全取心井深世界纪录。本文介绍了该井的施工过程,对该井的钻进时间、钻探效率和回次进尺长度进行了系统的统计与分析。通过分析,对影响海上深部科学钻探效率的海况、后勤保障等因素进行了简单的阐述,为提高海上深孔钻探施工效率提供了参考依据。  相似文献