海上钢结构防腐蚀措施的研究     

李斌  石友强 《海岸工程》2007,26(2):53-56

针对海上钢结构严重腐蚀环境,分析了影响其腐蚀的主要因素,比较分析了钢结构常用的几种腐蚀防护方法。由于电弧喷涂复合涂层具有20 a以上的长效防腐寿命和涂层结合强度高、免维护等特点,因而成为海上钢结构防腐蚀的优选技术方案。还列举了国内外钢结构热喷涂防腐措施的应用实例及相关标准,对加强海上钢结构长效防腐的立法和推广应用提出了看法。  相似文献   

Reliability-Based Full-Life Cycle Optimum Design of Offshore Jacket Platform     

王立成  宋玉普 《中国海洋工程》2004,18(1):47-58

Based on the consideration of operation environment and structural property, an optimnm design model of offshore jacket platform is developed in this paper, namely, the reliability-based full-life cycle optimum design model. In this model, the time-dependent reliability assessment method for structural members is established by combination of the decrease, of sectional size and performance deterioration of material. The initial investment, maintenance cost and failure loss cost are assembled into the model. The total cost of the platform structure system in its full service period is chosen as the objective function, and the initial reliabilities of the layer elements partitioned in advance are taken as the design variables. Different models are obtained, depending on whether the system reliability eonstraint is considered or not. This optimum design model can result in the lowest full-life cost and the optimal initial layer reliability of an offshore jacket platform in the design of marine structures. The feasibility of this model is illustrated with an actual jacket platform in the Liaodong Gulf as an example.  相似文献   

Dynamic Load Identification in Time Domain   总被引：1，自引：0，他引：1  

Chu Liangcheng  Qu Natsi  Wu Ruifeng Lu Min  Yang Guojin Assistant  M. S.  Dalian University of Technology  Dalian Associate Professor  Dalian University of Technology  Dalian Professor  Dalian University of Technology  Dalian Engineer  Bohai Oil Company Senior Engineer  Bohai Oil Company 《中国海洋工程》1991,(3)

- In the time domain method the dynamic load is successfully identified when the accelerations, velocities and displacements or velocities and displacements of the structure are known. But in engineering practice or experiments usually only the acceleration response is recorded. In this paper an improved time domain method is proposed for dynamic load identification. In this method by using of Duhamel integral, only the acceleration response is required for load identification. As an application of the present method, the dynamic ice load on a Bohai offshore platform is identified based on some measured acceleration. The identified values of ice load are in good agreement with the measured ones.  相似文献   

A new look at the Rockall region, offshore Ireland     

J. Makris  A. Ginzburg  P.M. Shannon  A.W.B. Jacob  C.J. Bean  U. Vogt 《Marine and Petroleum Geology》1991,8(4)

A 700 km wide-angle reflection/refraction profile carried out in the central North Atlantic west of Ireland crossed the Erris Trough, Rockall Trough and Rockall Bank, and terminated in the western Hatton-Rockall Basin. The results reveal the presence of a number of sedimentary basins separated by basement highs. The Rockall Trough, with a sedimentary pile up to 5 km thick, is underlain by thinned continental crust 8–10 km thick. Some major fault block structures are identified, especially on the eastern margin of the Rockall Trough and in the adjacent Erris Trough. The Hatton-Rockall Basin is underlain by westward-thinning continental crust 22–10 km thick. Sedimentary strata are up to 5 km thick. The strata in the Rockall Trough and Hatton-Rockall Basin probably range in age from Late Palaeozoic to Cenozoic. However, the basins have different sedimentation histories and differ in structural style. The geometry of the crust and sediments suggests that the Rockall Trough originated by pure shear crustal stretching, associated with rift deposits and Cenozoic thermal sag strata. In contrast, the development of the Erris Trough, located on unthinned continental crust, was facilitated by shallow, brittle extension with little deep crustal attenuation. A two-layered crust occurs throughout the region. The lower crustal velocity in the Hatton-Rockall Basin is higher than that in the Rockall Trough. The velocity structure shows no indication of crustal underplating by upper mantle material in the region.  相似文献   

Two dimensional responses of fixed offshore platform in waves     

Toru Sawaragi  Masao Nochino 《Applied Ocean Research》1985,7(3):140-151

Responses of a four-legged offshore platform to wave forces are analysed by taking account of one torsional motion around the vertical axis which passes the centre of gravity of the structure, and two translational motions in the horizontal plane. Applying the spring-mass system with one degree-of-freedom to each mode of motion, a calculation method for predicting resultant dynamic displacements of the topdeck is developed. Both the inline force and the transverse force are considered as external forces. The calculated results are found to agree with experiments. Furthermore, the influence of seven important factors on the dynamic response is examined by the calculations. It is shown that the combination pattern of the direction factor of the transverse force is of importance in dynamic analysis.  相似文献   

Model Simplification and Parameter Modification for Offshore Platforms Using Experiment Data     

Xu Bin Tian Qianli Research Associate 《中国海洋工程》1993,(2)

- In this paper, a computation method has been developed so as to compare the finite element method (FEM) with the test results directly. The structure is divided into the "master" and "slave" degrees of freedom. The simplified model can be obtained with modal reduction. Then the design sensitivity analysis of the eigenvalues and eigenvectors has been carried out using the modal frequency and modal shape of the test. A two-story frame structure and a jacket model structure have been calculated. Meanwhile, the modified coefficient, the FEM computational and experimental values have been given. It has been shown that the FEM model modified using the test modal value is efficient.  相似文献   

数据库在荷兰海洋区测中的作用与地位     

王圣洁  陈鸿君 《海洋地质前沿》2002,18(8):23-28

荷兰海洋区测中十分重视数据库建设和信息化方法的应用，荷兰海洋区测数据库包括3类不同的层次，如项目级数据库Archive management system、部门级数据库IMKMG和企业级数据库DINO。数据库技术的使用保证了区调成果的重复利用（Re-use）和可持续使用（Sustainability），是荷兰区调顺利完成以及成果得以广泛应用的重要技术基础。  相似文献   

基于AutoCAD三维海洋平台结构模型实用技术研究     

彭辉  聂武 《海洋工程》2007,25(3):26-31

以一个常见桩腿结构为例,介绍使用AutoCAD建立海洋平台结构三维数字模型。提取结构零件属性、生成零件明细表、合并所有零件、构造整个桩腿结构三维实体模型。查询桩腿结构质量和质心,自动生成桩腿结构视图的方法和操作过程。说明基于通用软件进行海洋平台结构三维数字模型的开发与应用切实可行。  相似文献   

Lectotype Optimization of Offshore Platforms by Use of Three-Scale Fuzzy Analytical Hierarchy Process     

WANG Licheng 《中国海洋工程》2001,(2):153-164

A Three-Scale Fuzzy Analytical Hierarchy Process (T-FAHP) is proposed by introducing the Three-Scale Analytical Hierarchy Process (T-AHP) and the trapezoid fuzzy number. A multi-objective optimization model based on the T-FAHP is presented subsequently, in which many factors influencing the lectotype of offshore platform are taken into account synthetically, such as the original investment, the maintenance cost, the ability of resisting fatigue and corrosion, the construction period, the threat to the environment, and so on. With this method, the experts can give the relatively precise ranking weight of each index and at the same time the requirement of consistence checking can be met. The result of a calculation example shows that the T-FAHP is practical.  相似文献   

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