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Study on the general layout of semi-submersible offshore drilling platforms based on process flow 被引量:2
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作者 岳吉祥 綦耀光 +2 位作者 肖文生 杨磊 杨轶普 《Journal of Marine Science and Application》 2009年第2期117-122,共6页
The general layout of 6th generation semi-submersible drilling platforms is the main factor impacting the efficiency of their drilling operations. This paper provides a compound/integrated algorithm based on process f... The general layout of 6th generation semi-submersible drilling platforms is the main factor impacting the efficiency of their drilling operations. This paper provides a compound/integrated algorithm based on process flow that is aimed at improving efficiency, while giving attention to stability and safety at the same time. The paper describes the process flow of dual drilling centers and a hierarchical division of rigs based on the different modes of transportation of various drilling support systems. The general layout-centripetal overall arrangement spatially was determined based on drilling efficiency. We derived our modules according to drilling functionality; the modules became our basic layout units. We applied different layout algorithm to mark out the upper and lower decks. That is, the upper deck was designed based on the lowest transportation cost while the lower deck's calculations were based on the best-fit scope. Storage configurations in columns and pontoons were also considered for the layout design. Finally the center of gravity was taken into consideration and the general layout was adjusted accordingly, to result in an optimal center of gravity. The methodology of the general layout can provide a reference for implementation of domestic designs of semi-submersible rigs. 展开更多
关键词 semi-submersible drilling platform general layout drilling process flow layout optimization group technology
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Dynamic Response Analysis of Semi-Submersible Floating Wind Turbine with Different Wave Conditions
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作者 Mingzhen Jiang Guanghui Qiao +4 位作者 Jiwen Chen Xuemei Huang Leian Zhang Yongshuang Wen Yuhuan Zhang 《Energy Engineering》 EI 2023年第11期2531-2545,共15页
To address the problem of poor wave resistance of existing offshore floating wind turbines,a new type of semisubmersible platform with truncated-cone-type upper pontoons is proposed by combining the characteristics of... To address the problem of poor wave resistance of existing offshore floating wind turbines,a new type of semisubmersible platform with truncated-cone-type upper pontoons is proposed by combining the characteristics of offshore wind turbine semi-submersible floating platforms.Based on the coupled hydrodynamic,aerodynamic,and mooring force physical fields of FAST,the surge,heave,pitch,and yaw motions responses of the floating wind turbine under different wave heights and periods are obtained,and the mooring line tension responses are also obtained;and compare the dynamic response of the new semi-submersible platform with the OC4-DeepCwind platformat six degrees of freedom.The results show that different wave conditions have obvious effects on the heave and pitch motions of the new floating wind turbine,and fewer effects on the surge and yaw motions;the tensegrity response of the mooring system is more affected by the wave conditions;compared with the OC4-DeepCwind floating wind turbine,the pitch and roll response of the new floating wind turbine has been significantly reduced and has good stability. 展开更多
关键词 Floating wind turbine semi-submersible platform wave loading different wave conditions dynamic response
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Sensitivity Analysis of Air Gap Motion with Respect to Wind Load and Mooring System for Semi-Submersible Platform Design 被引量:5
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作者 霍发力 聂焱 +2 位作者 杨德庆 董刚 崔锦 《China Ocean Engineering》 SCIE EI CSCD 2016年第4期535-548,共14页
A design of semi-submersible platform is mainly based on the extreme response analysis due to the forces experienced by the components during lifetime. The external loads can induce the extreme air gap response and po... A design of semi-submersible platform is mainly based on the extreme response analysis due to the forces experienced by the components during lifetime. The external loads can induce the extreme air gap response and potential deck impact to the semi-submersible platform. It is important to predict air gap response of platforms accurately in order to check the strength of local structures which withstand the wave slamming due to negative air gap. The wind load cannot be simulated easily by model test in towing tank whereas it can be simulated accurately in wind tunnel test. Furthermore, full scale simulation of the mooring system in model test is still a tuffwork especially the stiffness of the mooring system. Owing to the above mentioned problem, the model test results are not accurate enough for air gap evaluation. The aim of this paper is to present sensitivity analysis results of air gap motion with respect to the mooring system and wind load for the design of semi-submersible platform. Though the model test results are not suitable for the direct evaluation of air gap, they can be used as a good basis for tuning the radiation damping and viscous drag in numerical simulation. In the presented design example, a numerical model is tuned and validated by ANSYS AQWA based on the model test results with a simple 4 line symmetrical horizontal soft mooring system. According to the tuned numerical model, sensitivity analysis studies of air gap motion with respect to the mooring system and wind load are performed in time domain. Three mooring systems and five simulation cases about the presented platform are simulated based on the results of wind tunnel tests and sea-keeping tests. The sensitivity analysis results are valuable for the floating platform design. 展开更多
关键词 mooring system air gap semi-submersible platform radiation damping viscous drag
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Wave load computation in direct strength analysis of semi-submersible platform structures 被引量:7
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作者 ZHANGHai-bin RENHui-long DAIYang-shan GEFei 《Journal of Marine Science and Application》 2004年第1期7-13,共7页
A wave load computation approach in direct strength analysis of semi-submersible platform structures was presented in this paper. Considering the differences in shape of pontoon, column and beam, the combination of ac... A wave load computation approach in direct strength analysis of semi-submersible platform structures was presented in this paper. Considering the differences in shape of pontoon, column and beam, the combination of accumulative chord length cubic parameter spline theory and analytic method was adopted for generating the wet surface mesh of platform. The hydrodynamic coefficients of platform were calculated by the three-dimensional potential flow theory of the linear hydrodynamic problem for platform with low forward speed. The equation of platform motions was established and solved in frequency domain, and the responses of wave-induced loads on the platform can be obtained. With the interpolation method being utilized, the pressure loads on shell elements for finite element analysis (FEA) were converted from those on the hydrodynamic computation mesh, which pave the basis for FEA with commercial software.A computer program based on this method has been developed, and a calculation example of semi-submersible platform was illustrated.Analysis results show that this method is a satisfying approach of wave loads computation for this kind of platform. 展开更多
关键词 semi-submersible platform wave loads mesh-generating direct strength analysis
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Dynamic Performance of a Semi-Submersible Platform Subject to Wind and Waves 被引量:3
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作者 ZHU Hang OU Jinping 《Journal of Ocean University of China》 SCIE CAS 2011年第2期127-134,共8页
By applying experimental and numerical simulations, the motion performance of a semi-submersible platform with mooring positoning system under combined actions of wind and waves is studied. The numerical simulation is... By applying experimental and numerical simulations, the motion performance of a semi-submersible platform with mooring positoning system under combined actions of wind and waves is studied. The numerical simulation is conducted by the method of nonlinear time domain coupled analysis, and the mooring forces are calculated by the piecewise extrapolating method. The scale in the model experiment is 1:100, and the mooring system of the model is designed with the method of equivalent water-depth truncation by comparing the numerical and the experimental results, the platform motion and mooring forces subject to wind and waves are investigated. The results indicate that the numerically simulated mooring forces agree well with the experimental results in static equivalent field, but show some difference in dynamic equivalent field; the numerically simulated platform motions coincide well with the experimental results. The maximum motion of the platform under operating conditions is 20.5 m. It means that the horizontal displacement is 2% less than the water depth, which satisfies the operating requirements. 展开更多
关键词 semi-submersible platform WIND WAVES numerical simulation experimental simulation
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Investigation of the Hydrodynamic Performance of a Novel Semi-Submersible Platform with Multiple Small Columns 被引量:1
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作者 SONG Xiancang WANG Shuqing +1 位作者 LI Huajun LI Tao 《Journal of Ocean University of China》 SCIE CAS CSCD 2019年第1期108-122,共15页
This paper presents a novel semi-submersible(SEMI) platform concept, called the multiple small columns(MSC) SEMI that improves upon the hydrodynamic performance of the conventional SEMI. Unlike the conventional SEMI, ... This paper presents a novel semi-submersible(SEMI) platform concept, called the multiple small columns(MSC) SEMI that improves upon the hydrodynamic performance of the conventional SEMI. Unlike the conventional SEMI, the proposed MSC SEMI utilizes multiple small circular columns to support the deck and a large pontoon that increases the structural displacement. The novelty of the MSC SEMI is its reduction of the hydrodynamic load on the structure and suppression of its motion response, particularly in the heave direction. The MSC SEMI has the advantages of increasing the added mass, radiation damping, and natural period of the structure. A comprehensive investigation of the hydrodynamic performance of the novel MSC SEMI is conducted in both the time and frequency domains with a special focus on the resulting hydrodynamic load and motion response. Numerical simulation results demonstrate that the MSC SEMI concept can reduce the hydrodynamic load and motion response and improve the hydrodynamic performance of SEMIs as expected. 展开更多
关键词 semi-submersible platform MULTIPLE SMALL COLUMNS HYDRODYNAMIC performance coupled dynamic analysis
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Structural Stress Monitoring and FEM Analysis of the Cutting Operation of the Main Bracket of A Semi-Submersible Platform 被引量:1
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作者 KOU Yu-feng YANG Jian-min +3 位作者 XU Sheng-wen PENG Tao LIU Jun WU Zhuo-wei 《China Ocean Engineering》 SCIE EI CSCD 2019年第6期649-659,共11页
For a semi-submersible platform in repair, the eight old main brackets which connect columns with pontoons need to be replaced by new ones. In order to ensure the safety of the cutting operation of the old main bracke... For a semi-submersible platform in repair, the eight old main brackets which connect columns with pontoons need to be replaced by new ones. In order to ensure the safety of the cutting operation of the old main bracket and calculate the initial stress condition of new main bracket, the structural stress monitoring of eight key spots is carried out, and then the calibrated finite element model is established according to the field monitoring results. Before cutting the main bracket and all associated structures, eight rectangular rosettes were installed, and a tailored cutting scheme was proposed to release the initial stress, in which the main bracket and associated column and pontoon plates were partly cut. During the cutting procedure, the strains of the monitoring spots were measured, and then the structural stress of the monitored spots were obtained. The stress variation characteristics at different spots during the initial cutting operation were shown and the initial stress condition of the monitored spots was figured out. The loading and support conditions of the semi-submersible platform were calibrated based on the measured initial stress condition, which made the finite element model more credible. The stress condition with the main bracket and associated structures being entirely cut out is analyzed by the Finite Element Method (FEM), which demonstrates the cutting operation to be safe and feasible. In addition, the calibrated finite element model can be used to calculate the initial stress condition of the new main bracket, which will be very helpful for the long-term stress monitoring on the main bracket. 展开更多
关键词 semi-submersible platform main bracket cutting operation field stress monitoring FEM analysis
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A Prediction Method of Internal Solitary Wave Loads on the Semi-Submersible Platform 被引量:1
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作者 ZHANG Jing-jing CHEN Ke +1 位作者 YOU Yun-xiang HAN Pan-pan 《China Ocean Engineering》 SCIE EI CSCD 2022年第3期464-473,共10页
An investigation into the prediction method for internal solitary waves(ISWs)loads on the columns and caissons of the semi-submersible platform found on three kinds of internal solitary wave theories and the modified ... An investigation into the prediction method for internal solitary waves(ISWs)loads on the columns and caissons of the semi-submersible platform found on three kinds of internal solitary wave theories and the modified Morison Equation is described.The characteristics of loads exerted on the semi-submersible platform model caused by the ISWs have been observed experimentally,and the inertial and drag coefficients in Morison Equation are determined by analyzing the forces of experiments.From the results,it is of interest to find that Reynolds number,KC number and layer thickness ratio have a considerable influence on the coefficients.The direction of incoming waves,how-ever,is almost devoid of effects on the coefficients.The drag coefficient of columns varies as an exponential function of Reynolds number,and inertia coefficient of columns is a power function related to KC number.Meanwhile,the drag coefficient of caissons is approximately constant in terms of regression analysis of experimental data.The results from different experimental conditions reveal that the inertia coefficient of caissons appears to be exponential correlated with upper layer depths. 展开更多
关键词 semi-submersible platform Morison equation model test ISWs COEFFICIENTS
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Conceptual Design of a Deep Draft Semi-Submersible Platform with a Moveable Heave-Plate 被引量:2
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作者 ZHU Hang OU Jinping ZHAI Gangjun 《Journal of Ocean University of China》 SCIE CAS 2012年第1期7-12,共6页
Based on the principle of turned mass damper(TMD) systems,the conceptual design of semi-submersible platform with a moveable heave-plate(MHS) has been put forward.The heave motion response amplitude operator(RAO) and ... Based on the principle of turned mass damper(TMD) systems,the conceptual design of semi-submersible platform with a moveable heave-plate(MHS) has been put forward.The heave motion response amplitude operator(RAO) and viscous damping of the MHS platform are calculated by iteration,and the coupling stiffness between the MHS hull and the heave-plate is optimized to decrease the maximum heave motion response of the MHS hull under 10-year survival conditions in the South China Sea.The nu-merical results indicate that the heave motion RAO of the MHS hull can be decreased in the range of predominant wave frequencies,which may provide some reference to the heave motion control of offshore platforms. 展开更多
关键词 semi-submersible platform heave-plate TMD MHS platform
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Application of a Newly Built Semi-submersible Vessel for Transportation of a Tension Leg Platform 被引量:1
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作者 Dagang Zhang WeiyingSun Zhixia Fan 《Journal of Marine Science and Application》 2012年第3期341-350,共10页
Transportation of tension leg platform (TLP) structures for a long distance has always been associated with the use of a heavy semi-transport vessel. The requirements of this type of vessel are always special, and t... Transportation of tension leg platform (TLP) structures for a long distance has always been associated with the use of a heavy semi-transport vessel. The requirements of this type of vessel are always special, and their availability is limited. To prepare for the future development of South China Sea deepwater projects, the China Offshore Oil Engineering Corporation has recently built a heavy lift transport vessel-Hai Yang Shi You 278. This semi-submersible vessel has a displacement capacity of 50k DWT, and a breath of 42 meters. Understanding the vessel's applicability and preparing it for use in future deepwater projects are becoming imminent needs. This paper reviews the current critical issues associated with TLP transportation and performs detailed analysis of the designed TLP during load-out and transportation. The newly built COOEC transportation vessel HYSY 278 was applied to dry transport of the TLP structure from the COOEC fabrication yard in Qingdao to an oil field in South China Sea. The entire process included the load-out of the TLP structure from the landsite of the fabrication yard, the offloading and float-on of the platform from the vessel, the dry transport of the TLP over a long distance, and the final offloading of the platform. Both hydrodynamic and structure analysis were performed to evaluate the behavior of the transport vessel and TLP structure. Special attention was paid to critical areas associated with the use of this new vessel, along with any potential limitations. The results demonstrate that HYSY 278 can effectively be used for transporting the structure with proper arrangement and well-prepared operation. The procedure and details were presented on the basis of the study results. Special attention was also given to discussion on future use based on the results from the analysis. 展开更多
关键词 dry transport HYSY 278 tension leg platform (TLP) structure heavy semi-submersible transportvessel floating structure
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Effect of Failure Mode of Taut Mooring System on the Dynamic Response of A Semi-Submersible Platform
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作者 WANG Teng HAO jun-jie +2 位作者 WU Xiao-ni LI Ye WANG Xiao-tong 《China Ocean Engineering》 SCIE EI CSCD 2021年第6期841-851,共11页
Mooring system failure can lead to largely different dynamic response of floating structures when compared to the response under the condition of intact mooring system.For a semi-submersible platform with taut mooring... Mooring system failure can lead to largely different dynamic response of floating structures when compared to the response under the condition of intact mooring system.For a semi-submersible platform with taut mooring system under extreme environmental conditions,the typical mooring system failure includes anchor line breaking failure due to the broken anchor line,and the anchor dragging failure caused by the anchor failure in the seabed soil due to the shortage of the anchor bearing capacity.However,study on the mooring failure caused by anchor failure is rare.The current work investigates the effect of three failure modes of taut mooring system on dynamic response of a semi-submersible platform,including one line breaking failure,two lines breaking failure,and one line breaking with one line attached anchor dragging failure.The nonlinear polynomial mooring line model in AQWA was used with integrating the load and displacement curve from the anchor pulling study to characterize the anchor dragging behavior for mooring system failure caused by the anchor failure.The offsets of the platform and the tension of mooring lines were analyzed for mooring system failure with 100-year return period.It is found that the mooring failure of one line breaking with one line attached anchor dragging is a case between the other two mooring failures.The traditional mooring analysis considering only the damaged condition with one line breaking is not safe enough.And the simple way of mooring analysis of two lines breaking is too conservative for the costly offshore engineering. 展开更多
关键词 taut mooring system failure semi-submersible platform dynamic response anchor dragging line breaking
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Predictive Control and Implementation of Mooring Automatic Positioning System for Deepwater Semi-Submersible Platform
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作者 Tao Sun Wenbin Gui +1 位作者 Zhigang Yu Zhimin Gao 《Intelligent Control and Automation》 2014年第4期233-244,共12页
The automatic positioning control of mooring system for deepwater semi-submersible platform has become a key issue in the research and development field of deep-sea resources. The Dual-Stage Actuator (DSA) proposed in... The automatic positioning control of mooring system for deepwater semi-submersible platform has become a key issue in the research and development field of deep-sea resources. The Dual-Stage Actuator (DSA) proposed in this paper can replace the single actuator to achieve the high speed and high precision positioning by cooperative control. The relative model and control algorithm of motion trajectory (CAMT) are designed and validated, which proves that the method proposed in this paper is effective. 展开更多
关键词 DEEPWATER semi-submersible platform MOORING System AUTOMATIC Positioning ANCHOR Predictive Control
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Implementation of Mooring Automatic Positioning System for Deepwater Semi-Submersible Platform Based on Dual-Stage Actuator
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作者 Tao Sun Wenbin Gui +1 位作者 Zhigang Yu Zhimin Gao 《Open Journal of Modelling and Simulation》 2014年第2期67-76,共10页
The automatic positioning control of mooring system for deepwater semi-submersible platform has become a key issue in the research and development field of deep-sea resources. The Dual- Stage Actuator (DSA) proposed i... The automatic positioning control of mooring system for deepwater semi-submersible platform has become a key issue in the research and development field of deep-sea resources. The Dual- Stage Actuator (DSA) proposed in this paper can replace the single actuator to achieve the high speed and high precision positioning by cooperative control. The relative model and control algorithm of motion trajectory (CAMT) are designed and validated, which proves that the method proposed in this paper is effective. 展开更多
关键词 DEEPWATER semi-submersible platform MOORING AUTOMATIC Positioning Dual-Stage Actuator (DSA) HIGH Speed and HIGH Precision the Control Algorithm of Motion TRAJECTORY (CAMT)
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Hydrodynamic Comparison of a Semi-submersible,TLP,and Spar:Numerical Study in the South China Sea Environment 被引量:5
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作者 Binbin Li Kun Liu +1 位作者 Gongwei Yan Jinping Ou 《Journal of Marine Science and Application》 2011年第3期306-314,共9页
The South China Sea contains tremendous oil and gas resources in deepwater areas. However, one of the keys for deepwater exploration, the investigation of deepwater floating platforms, is very inadequate. In this pape... The South China Sea contains tremendous oil and gas resources in deepwater areas. However, one of the keys for deepwater exploration, the investigation of deepwater floating platforms, is very inadequate. In this paper, the authors studied and compared the hydrodynamics and global motion behaviors of typical deepwater platforms in the South China Sea environment. The hydrodynamic models of three main types of floating platforms, e.g. the Semi-submersible, tension leg platform (TLP), and Truss Spar, which could potentially be utilized in the South China Sea, were established by using the 3-D potential theory. Additionally, some important considerations which significantly influence the hydrodynamics were given. The RAOs in frequency domains as well as global motions in time domains under time-varying wind, random waves, and current in 100-y, 10-y, and 1-y return period environment conditions were predicted, compared, and analyzed. The results indicate that the heave and especially the pitch motion of the TLP are favorable. The heave response of the Truss Spar is perfect and comparable with that of the TLP when the peak period of random waves is low. However, the pitch motion of Truss Spar is extraordinarily lar^er than that of Semi-submersible and TLP. 展开更多
关键词 semi-submersible Spar tension leg platform (TLP) South China Sea HYDRODYNAMICS
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Numerical and Experimental Study on Hydrodynamic Performance of A Novel Semi-Submersible Concept 被引量:2
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作者 GAO Song TAO Long-bin +2 位作者 KOU Yu-feng LU Chao SUN Jiang-long 《China Ocean Engineering》 SCIE EI CSCD 2018年第2期144-156,共13页
The Multiple Column Platform(MCP) semi-submersible is a newly proposed concept, which differs from the conventional semi-submersibles, featuring centre column and middle pontoon. It is paramount to ensure its structur... The Multiple Column Platform(MCP) semi-submersible is a newly proposed concept, which differs from the conventional semi-submersibles, featuring centre column and middle pontoon. It is paramount to ensure its structural reliability and safe operation at sea, and a rigorous investigation is conducted to examine the hydrodynamic and structural performance for the novel structure concept. In this paper, the numerical and experimental studies on the hydrodynamic performance of MCP are performed. Numerical simulations are conducted in both the frequency and time domains based on 3D potential theory. The numerical models are validated by experimental measurements obtained from extensive sets of model tests under both regular wave and irregular wave conditions. Moreover, a comparative study on MCP and two conventional semi-submersibles are carried out using numerical simulation.Specifically, the hydrodynamic characteristics, including hydrodynamic coefficients, natural periods and motion response amplitude operators(RAOs), mooring line tension are fully examined. The present study proves the feasibility of the novel MCP and demonstrates the potential possibility of optimization in the future study. 展开更多
关键词 multiple column platform(MCP) semi-submersible platform numerical simulation model test response amplitude operators(RAOs)
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Strength Analysis on Brace Structure for Semi-Submersible in Consideration of Wave Slamming 被引量:2
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作者 HUO Fa-li YAO Zhi +2 位作者 ZHANG Jian WANG Jun-wei DONG Bin 《China Ocean Engineering》 SCIE EI CSCD 2018年第5期536-545,共10页
Slamming on bracings of column stabilized units shall be considered as a possible limiting criterion under transit condition based on the requirements in DNV-OS-C103. However, the wave slamming loads under survival co... Slamming on bracings of column stabilized units shall be considered as a possible limiting criterion under transit condition based on the requirements in DNV-OS-C103. However, the wave slamming loads under survival condition were ignored for the strength analysis of the brace structures in many semi-submersible projects. In this paper, a method of strength analysis of brace structure is proposed based on the reconstruction and extrapolation of numerical model. The full-scale mooring system, the wind, wave and current loads can be considered simultaneously. Firstly,the model tests of the semi-submersible platform in wind tunnel and wave tanker have been carried out. Secondly,the numerical models of the platform are reconstructed and extrapolated based on the results of model tests. Then, a nonlinear numerical analysis has been conducted to study the wave slamming load on brace in semi-submersible platform through the reconstructed and extrapolated numerical model. For the randomness of wave load, ten subcases under each condition have been carried out. The value of the 90% Gumble distribution values of the ten subcases are used. Finally, the strength on brace structure has been analyzed considering the wave slamming. The wave slamming loads have been compared between the survival condition and transit condition with the method. The results indicate that wave slamming under survival condition is more critical than that under transit condition.Meanwhile, the wave slamming is significant to the structural strength of the brace. It should be overall considered in the strength analysis of the brace structure. 展开更多
关键词 semi-submersible platform wave slamming brace structure structural strength
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Semi-submersible Offshore Coupled Motion in Irregular Waves
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作者 Baoji Zhang Ying Wang 《Journal of Marine Science》 2020年第2期27-37,共11页
In order to predict the hydrodynamic performance of semi-submersible offshore platform accurately,based on CFD theory,continuous equation and N-S equation as the control equation,RNG type k-εmodel as turbulence model... In order to predict the hydrodynamic performance of semi-submersible offshore platform accurately,based on CFD theory,continuous equation and N-S equation as the control equation,RNG type k-εmodel as turbulence model,using the finite difference method to discretize the control equation,using the Semi-Implicit Method for Pressure Linked Equation(SIMPLE)algorithm to solve the control equation,using the VOF method to capture the free surface.The numerical wave tank of irregular wave is established,and the wave force and motion response of the semi-submersible platform under irregular wave are studied.Based on the Jonswap spectrum density function,for a certain area of two irregular waves(South China sea,a-ten-year return period,a-hundred-year return period)sea condition,five wave direction Angle(0°,30°,45°,60°,90°),a total of 10 kinds of conditions of the motion response of semi-submersible platform are simulated,through analysis and comparison of simulation results,the influence law of wave angle,wave period and wave height on platform motion is obtained.Compared with the experimental values,the results of heave and pitch are close to the experimental data under the sea condition of 2,0 degree wave angles.The research results in this paper can provide reference for the design and motion response prediction of practical semi-submersible offshore platforms. 展开更多
关键词 semi-submersible offshore platform CFD method Irregular waves Motion response Wave force
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Fuzzy Optimum Model of Semi-Structural Decision for Lectotype Optimization of Offshore Platforms 被引量:10
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作者 陈守煜 伏广涛 +1 位作者 王建明 刘刚 《China Ocean Engineering》 SCIE EI 2001年第4期453-466,共14页
In the process of concept design of offshore platforms, it is necessary to select the best from feasible alternatives through comparison and filter. The criterion set, used to evaluate and select the satisfying altern... In the process of concept design of offshore platforms, it is necessary to select the best from feasible alternatives through comparison and filter. The criterion set, used to evaluate and select the satisfying alternative, consists of many qualitative and quantitative factors. Therefore, the selection is a problem of multicriteria and semi-structural decision-making. Different from traditional methods in semi-structural decision-making, a new framework and methodology is presented in this paper for evaluation of offshore platform alternatives, First, the criterion set is established for the evaluation of alternatives. Next, the approach is studied to construct the relative membership degree matrix, in which both qualitative and quantitative factors are consistent with the uniform calculating standard. And then a new weight-assessing method is developed for calculation of the weights based on the relative membership degree matrix. Finally, a multi-hierarchy fuzzy optimum model is adopted to select the satisfying offshore platform alternative. A case study shows that the new framework and methodology are scientific, reasonable and easy to use in practice. 展开更多
关键词 offshore platform lectotype optimization semi-structure relative membership degree matrix weightvector fuzzy optimum
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Semi-Active Control of Wave-Induced Vibration for Offshore Platforms by Use of MR Damper 被引量:8
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作者 李华军 土树青 秘春艳 《China Ocean Engineering》 SCIE EI 2002年第1期33-40,共8页
The objective of the present research is to examine the effectiveness of the lateral vibration control of wave-excited response of offshore platforms with magneto-rheological (MR) damper. In this study, the offshore p... The objective of the present research is to examine the effectiveness of the lateral vibration control of wave-excited response of offshore platforms with magneto-rheological (MR) damper. In this study, the offshore platform is simplified to be a singled degree-of-freedom (SDOF) system by extracting the first vibration mode of the structure. The external 'generalized' wave force is determined with a white noise via a designed filter. A semi-active control method based on optimal control theory is proposed considering that the yield stress of the MR damper can he varied continuously within a certain range. The dynamics of SDOF structure coupled with the MR damper is investigated. Numerical simulation demonstrates that the MR damper with this control strategy can significantly reduce the maximum responses and the root-mean-square (RMS) values. 展开更多
关键词 semi-active control offshore platform vibration reduction wave loading magneto-rheological damper
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Semi-Active TLCD Control of Fixed Offshore Platforms Using Artifical Neural Networks 被引量:2
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作者 李宏男 霍林生 《海洋工程:英文版》 2003年第2期277-282,共6页
In this paper, the control method for fixed offshore platforms using semi-active tuned liquid column damper (TLCD) is presented. The equation of motion for the platform-TLCD control system is given and the semi-active... In this paper, the control method for fixed offshore platforms using semi-active tuned liquid column damper (TLCD) is presented. The equation of motion for the platform-TLCD control system is given and the semi-active control strategy is established. A back propagation artificial neural network (ANN) is used to adjust the orifice opening of TLCD because of the nonlinear motion of liquid in TLCD. The effectiveness of the control method is verified by numerical examples. 展开更多
关键词 fixed offshore platform tuned liquid column damper semi-active control neural network
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