Umbilical cable recovery load analysis     

闫澍旺  贾沼霖  封晓伟  李世涛 《中国海洋工程》2013,27(3):351-358

Umbilical cable is a kind of integrated subsea cable widely used in the exploration and exploitation of oil and gas field. The severe ocean environment makes great challenges to umbilical maintenance and repair work. Damaged umbilical is usually recovered for the regular operation of the offshore production system. Analysis on cables in essence is a two-point boundary problem. The tension load at the mudline must be known first, and then the recovery load and recovery angle on the vessel can be solved by use of catenary equation. The recovery analysis also involves umbilical-soil interaction and becomes more complicated. Calculation methods for recovery load of the exposed and buried umbilical are established and the relationship between the position of touch down point and the recovery load as well as the recovery angle and recovery load are analyzed. The analysis results provide a theoretical reference for offshore on-deck operation.  相似文献   

Stress Wave Propagation Analysis on Vortex-Induced Vibration of Marine Risers     

LI Hua-jun  WANG Chao  LIU Fu-shun  HU Sau-Lon James 《海洋工程》2017,31(1):30-36

To analyze the stress wave propagation associated with the vortex-induced vibration (VIV) of a marine riser, this paper employed a multi-signal complex exponential method. This method is an extension of the classical Prony''s method which decomposes a complicated signal into a number of complex exponential components. Because the proposed method processes multiple signals simultaneously, it can estimate the "global" dominating frequencies (poles) shared by those signals. The complex amplitude (residues) corresponding to the estimated frequencies for those signals is also obtained in the process. As the signals were collected at different locations along the axial direction of a marine riser, the phenomena of the stress wave propagation could be analyzed through the obtained residues of those signals. The Norwegian Deepwater Program (NDP) high mode test data were utilized in the numerical studies, including data sets in both the in-line (IL) and cross-flow (CF) directions. It was found that the most dominant component in the IL direction has its stress wave propagation along the riser being dominated by a standing wave, while that in the CF direction dominated by a traveling wave.  相似文献   

深部软岩巷道喷射钢纤维混凝土支护技术   总被引：12，自引：1，他引：12  

周宏伟  谢和平  董正亮  张志林  张敬书  方晓瑜 《工程地质学报》2001,9(4):393-398

针对深部软岩的基本特征, 提出了深部软岩巷道支护的新思路, 即改变现有的锚喷作业顺序, 并通过在素喷混凝土中掺入适量钢纤维的方法来改善混凝土的整体力学性能, 使之更好地适应软岩巷道大变形的需要。借助数值模拟, 进行了支护方案的对比分析, 并提出了合理的支护方案。  相似文献   

The contamination of former iron and steel works sites   总被引：3，自引：0，他引：3  

A. J. Harber  R. A. Forth 《Environmental Geology》2001,40(3):324-330

 Former iron and steel works sites are significant in terms of their size, number, degree of contamination, and their wide distribution in the United Kingdom. They are likely to have become chemically contaminated with a wide range of substances from the manufacture of iron and steel, and the many associated processes. Associated processes include coke-production, metal refining and finishing. Contamination by metals, inorganic and organic compounds, acids/alkalis and asbestos is common on such sites. The aim of this research was to draw together information on the contamination of former iron and steel works through a review of current literature and by the use of examples and case studies from the UK. The style of the paper is loosely based on an Inter-departmental Committee for Research in Contaminated Land (ICRCL) style guidance note, with case studies and examples. Received: 11 October 1999 · Accepted: 8 March 2000  相似文献   

武钢镁碳砖首次用于盛钢桶衬砖的侵蚀机理研究     

沈上越  苏良赫 《现代地质》1991,5(1):51-57

作者对我国武钢转炉盛钢桶镁碳砖的理化性能、使用条件,侵蚀情况等进行了详细的研究,在渣线处,它明显地优于镁砖.同时,在镁碳砖渐变带与反应带之间发现—镁铝尖晶石层,有延缓钢渣的锓蚀作用,并从热力学计算揭示了脱碳层及镁铝尖晶石层的形成,提出了增强衬砖寿命的具体改进措施,具有重要的理论和实际意义.  相似文献   

钢悬链式立管与非线性海床土相互作用分析方法研究   总被引：1，自引：1，他引：0  

梁宁  黄维平  杨超凡 《海洋工程》2016,34(1):40-49

对基于大挠度柔性梁理论的立管动力分析程序CABLE 3D改编,将原程序中立管受到线性海床的弹性支撑力扩充为立管受到的海床垂向力充分考虑管土非线性相互作用,使新程序中立管与海床土的相互作用遵循p-y曲线。采用伽辽金方法在空间内离散立管的动态方程,最终采用Newmark-β法进行时域内迭代求解。利用改编后的新程序分别研究了立管与线性海床土和非线性海床土相互作用的对比以及不同垂荡幅值情况下立管的动态响应。研究表明,非线性海床土能够更加准确地模拟真实的管土相互作用,触地点区域的节点会经历不同的管土相互作用过程。  相似文献   

Analysis of Optimization for Preliminary Design of Multi-Component Mooring Systems     

余龙  谭家华 《中国海洋工程》2005,19(2):299-308

Multi-component mooring systems become widely used in deep water position-keeping of drilling and production platforms. However, versatile materials make it difficult to design appropriate mooring lines made of several segments. Based on catenary equations of a multi-component mooring line at a specific water depth, this paper establishes a minimum model for designing this kind of lines. The model is solved by Genetic Algorithm and Multi-Objective Planning respectively. The model is verified by its application to a practical mooring design assigranent-a quasi-static analysis for a largesemi-submersible. The optimal result is finally obtained with the aid of design graphs.  相似文献   

陡峭S形柔性管初始形状计算     

朱胜昌  甘锡林  杨显成 《海洋工程》1994,(1)

本文采用悬链线方程的解，推导出陡峭Ｓ形柔形管初始形状的计算公式，计算出柔性管的初始形状、张力和弯矩，与国外资料的实例计算进行对比表明，结果相当一致。  相似文献   

钢材在海水—海气变换界面区的腐蚀行为     

侯保荣  西方篤  水流徹 《海洋与湖沼》1995,26(5):514-519

于1993年9月通过对241A，24KU，SS41三个不同钢种极化曲线的测定，对镜层本身的氧化还原电流的测定及X线分析，研究在海水一海气交换界面区锈层在腐蚀中所起的作用。结果表明，海一气交换界面区的钢由于锈层本身的氧化还原反应，其阴极电流均较裸钢为大，这说明锈层的还原反应起着重要作用．根据锈层本身的还原时间和还原电位，可以在某种程度上评价钢材本身耐腐蚀性能的好坏。  相似文献   

Large deformation three-dimensional static analysis of deep water marine risers     

Michael M. Bernitsas  John E. Kokarakis  Asjhar Imron 《Applied Ocean Research》1985,7(4):178-187

The problem of static three-dimensional, nonlinear, large deformation response of a marine riser is formulated within small strain theory and solved numerically. This type of analysis is necessary, for the new generation of drilling and production risers. The mathematical model takes properly into account the effects of internal and external pressure and the complete nonlinear boundary conditions, without linearizing the follower forces. The extensibility or inextensibility condition is used as the constitutive relation in the tangential direction. Torsion and bending are coupled. The external load and the boundary conditions are deformation dependent. A solution method is developed based on an incremental finite element algorithm, which involves a prediction-correction scheme. In the correction phase deformation dependent quantities are updated. The extensibility or inextensibility condition is used to reduce the degrees of freedom of the system. The numerical results of the developed computer code compare very well with available semi-analytical and numerical solutions. Three numerical applications are used to demonstrate the importance of large deformation, nonlinear and three-dimensional analyses.  相似文献