Construction crane vessels make use of dynamic positioning(DP)systems during the installation and removal of offshore structures to maintain the vessel’s position.Studies have reported cases of instability of DP syst...Construction crane vessels make use of dynamic positioning(DP)systems during the installation and removal of offshore structures to maintain the vessel’s position.Studies have reported cases of instability of DP systems during offshore operation caused by uncertainties,such as mooring forces.DP"robustification"for heavy lift operations,i.e.,handling such uncertainties systematically and with stability guarantees,is a long-standing challenge in DP design.A new DP method,composed by an observer and a controller,is proposed to address this challenge,with stability guarantees in the presence of uncertainties.We test the proposed method on an integrated cranevessel simulation environment,where the integration of several subsystems(winch dynamics,crane forces,thruster dynamics,fuel injection system etc.)allow a realistic validation under a wide set of uncertainties.展开更多
For a large floating vessel in waves,radiation damping is not an accurate prediction of the degree of roll unlike other degrees of freedom motion.Therefore,to get the knowledge of roll motion performance of deepwater ...For a large floating vessel in waves,radiation damping is not an accurate prediction of the degree of roll unlike other degrees of freedom motion.Therefore,to get the knowledge of roll motion performance of deepwater pipelay crane vessels and to keep the vessel working safety,the paper presents the relationship between a series of dimensionless roll damping coefficients and the roll response amplitude operator(RAO).By using two kinds of empirical data,the roll damping is estimated in the calculation flow.After getting the roll damping coefficient from the model test,a prediction of roll motion in regular waves is evaluated.According to the wave condition in the working region,short term statistics of roll motion are presented under different wave parameters.Moreover,the relationship between the maximal roll response level to peak spectral wave period and the roll damping coefficient is investigated.Results may provide some reference to design and improve this kind of vessel.展开更多
在海底管道铺设项目中,需要S-lay型铺管系统和J-lay型铺管系统完成铺管任务。分别对两个系统进行合理的空间布置设计,将其集成于同一艘深水起重铺管船。对双铺管系统协同作业进行设计,使两个系统共享管段预制线、共享弃置与回收(Abandon...在海底管道铺设项目中,需要S-lay型铺管系统和J-lay型铺管系统完成铺管任务。分别对两个系统进行合理的空间布置设计,将其集成于同一艘深水起重铺管船。对双铺管系统协同作业进行设计,使两个系统共享管段预制线、共享弃置与回收(Abandonment and Recovery,A&R)绞车系统,实现优势互补、提高铺管作业效率。展开更多
Current installation costs of offshore wind turbines(OWTs) are high and profit margins in the offshore wind energy sector are low, it is thus necessary to develop installation methods that are more efficient and pract...Current installation costs of offshore wind turbines(OWTs) are high and profit margins in the offshore wind energy sector are low, it is thus necessary to develop installation methods that are more efficient and practical. This paper presents a numerical study(based on a global response analysis of marine operations) of a novel procedure for installing the tower and Rotor Nacelle Assemblies(RNAs) on bottom-fixed foundations of OWTs. The installation procedure is based on the inverted pendulum principle. A cargo barge is used to transport the OWT assembly in a horizontal position to the site, and a medium-size Heavy Lift Vessel(HLV) is then employed to lift and up-end the OWT assembly using a special upending frame. The main advantage of this novel procedure is that the need for a huge HLV(in terms of lifting height and capacity) is eliminated. This novel method requires that the cargo barge is in the leeward side of the HLV(which can be positioned with the best heading) during the entire installation. This is to benefit from shielding effects of the HLV on the motions of the cargo barge, so the foundations need to be installed with a specific heading based on wave direction statistics of the site and a typical installation season. Following a systematic approach based on numerical simulations of actual operations, potential critical installation activities, corresponding critical events, and limiting(response) parameters are identified. In addition, operational limits for some of the limiting parameters are established in terms of allowable limits of sea states. Following a preliminary assessment of these operational limits, the duration of the entire operation, the equipment used, and weather-and water depth-sensitivity, this novel procedure is demonstrated to be viable.展开更多
基金supported by the Program of China Scholarship Council(CSC)(20167720003)the Special Guiding Funds Double First-Class(3307012001A)the Natural Science Foundation of China(62073074)。
文摘Construction crane vessels make use of dynamic positioning(DP)systems during the installation and removal of offshore structures to maintain the vessel’s position.Studies have reported cases of instability of DP systems during offshore operation caused by uncertainties,such as mooring forces.DP"robustification"for heavy lift operations,i.e.,handling such uncertainties systematically and with stability guarantees,is a long-standing challenge in DP design.A new DP method,composed by an observer and a controller,is proposed to address this challenge,with stability guarantees in the presence of uncertainties.We test the proposed method on an integrated cranevessel simulation environment,where the integration of several subsystems(winch dynamics,crane forces,thruster dynamics,fuel injection system etc.)allow a realistic validation under a wide set of uncertainties.
基金Supported by the Programme of Introducing Talents of Discipline to Universities(Grant No.B07019)
文摘For a large floating vessel in waves,radiation damping is not an accurate prediction of the degree of roll unlike other degrees of freedom motion.Therefore,to get the knowledge of roll motion performance of deepwater pipelay crane vessels and to keep the vessel working safety,the paper presents the relationship between a series of dimensionless roll damping coefficients and the roll response amplitude operator(RAO).By using two kinds of empirical data,the roll damping is estimated in the calculation flow.After getting the roll damping coefficient from the model test,a prediction of roll motion in regular waves is evaluated.According to the wave condition in the working region,short term statistics of roll motion are presented under different wave parameters.Moreover,the relationship between the maximal roll response level to peak spectral wave period and the roll damping coefficient is investigated.Results may provide some reference to design and improve this kind of vessel.
文摘在海底管道铺设项目中,需要S-lay型铺管系统和J-lay型铺管系统完成铺管任务。分别对两个系统进行合理的空间布置设计,将其集成于同一艘深水起重铺管船。对双铺管系统协同作业进行设计,使两个系统共享管段预制线、共享弃置与回收(Abandonment and Recovery,A&R)绞车系统,实现优势互补、提高铺管作业效率。
基金financially supported by the Research Council of Norway granted through the Department of Marine Technologythe Centre for Ships and Ocean Structures(CeSOS) and the the Centre for Autonomous Marine Operations and Systems(AMOS) from the Norwegian University of Science and Technology(NTNU)the financial support from Escuela Politécnica Nacional(EPN)through the project PIMI-15-03"Investigación y evaluación de sistemas innovadores de propulsión distribuida con ingestión de capa límite para mejorar la eficiencia propulsiva y térmica de vehículos aéreos no tripulados aplicados en los sectores:agrícola,medicina y vigilancia"
文摘Current installation costs of offshore wind turbines(OWTs) are high and profit margins in the offshore wind energy sector are low, it is thus necessary to develop installation methods that are more efficient and practical. This paper presents a numerical study(based on a global response analysis of marine operations) of a novel procedure for installing the tower and Rotor Nacelle Assemblies(RNAs) on bottom-fixed foundations of OWTs. The installation procedure is based on the inverted pendulum principle. A cargo barge is used to transport the OWT assembly in a horizontal position to the site, and a medium-size Heavy Lift Vessel(HLV) is then employed to lift and up-end the OWT assembly using a special upending frame. The main advantage of this novel procedure is that the need for a huge HLV(in terms of lifting height and capacity) is eliminated. This novel method requires that the cargo barge is in the leeward side of the HLV(which can be positioned with the best heading) during the entire installation. This is to benefit from shielding effects of the HLV on the motions of the cargo barge, so the foundations need to be installed with a specific heading based on wave direction statistics of the site and a typical installation season. Following a systematic approach based on numerical simulations of actual operations, potential critical installation activities, corresponding critical events, and limiting(response) parameters are identified. In addition, operational limits for some of the limiting parameters are established in terms of allowable limits of sea states. Following a preliminary assessment of these operational limits, the duration of the entire operation, the equipment used, and weather-and water depth-sensitivity, this novel procedure is demonstrated to be viable.
