The taut mooring system using synthetic fiber ropes has overcome the shortcomings such as the large self-weight of the mooring lines and provides better mooring performance for the floating structures.The polyester ro...The taut mooring system using synthetic fiber ropes has overcome the shortcomings such as the large self-weight of the mooring lines and provides better mooring performance for the floating structures.The polyester rope has attracted much attention among numerous synthetic fiber rope materials due to its lightweight,low price,corrosion resistance,and high strength.Thus,the mooring characteristics of it are worth studying.Polyester mooring lines are flexible in deep water,when a marine structure is moored by them,the geometric nonlinearity such as large displacement,large stretch,and large bending deformation,and the material nonlinearity like viscoelastic of the polyester ropes become complex integrated problems to be studied.Considering the nonlinear phenomenon,the simulation and calculation of a polyester line were carried out by the absolute nodal coordinate formulation(ANCF)in this paper since the ANCF method has advantages in dealing with the significant deformation problems of the flexible structures.In addition,a chain mooring line was also simulated for comparison,and the results show that the polyester ropes reduce the self-weight of the mooring lines and provide sufficient mooring strength at the same time,and the nonlinear phenomenon of the polyester ropes is different from that of the chain mooring lines.展开更多
The dynamic stiffness of polyester rope presents a complex mechanical performance,and the search for an appropriate calculation method to simulate this property is important.Distorted simulation results eventually yie...The dynamic stiffness of polyester rope presents a complex mechanical performance,and the search for an appropriate calculation method to simulate this property is important.Distorted simulation results eventually yield inaccurate line tension and vessel offset predictions,with the inaccuracy of vessel offset being particularly large.This paper proposes a flexible calculation method for the dynamic behavior of polyester rope based on the dynamic stiffness model.A real-time varying stiffness model of polyester rope is employed to simulate tension response through rope strain monitoring.Consequently,a simulation program is developed,and related case studies are conducted to explore the differences between the proposed method and analytical procedure of the DNV standard.Orcaflex is used to simulate the results of the latter procedure for comparison.Results show the convenience and straightforwardness of the procedure in the selection of an approximate dynamic stiffness model for polyester rope,which leads to an engineering-oriented approach.However,the proposed method is related to line property,which can directly reflect the dynamic behavior of polyester rope.Thus,a flexible calculation method may provide a reference for the simulation of the dynamic response of polyester mooring systems.展开更多
For intermediate water depths(typically ranging from 50 m to 80 m),designing steel catenary mooring systems for floating marine renewable energy(FMRE)platforms can be challenging due to the limited weight of suspended...For intermediate water depths(typically ranging from 50 m to 80 m),designing steel catenary mooring systems for floating marine renewable energy(FMRE)platforms can be challenging due to the limited weight of suspended mooring lines.This can substantially increase mooring line tensions following large platform offsets.In contrast,mooring systems using synthetic fibre ropes offer the potential to prevent large platform offsets while reducing peak mooring line tensions.In this study,novel semi-taut moor-ing systems incorporating polyester ropes and steel chains are proposed for a combined wind and wave energy system-the semi-submersible flap torus combination(STFC)concept,deployed at a 50 m wa-ter depth.The STFC integrates a semi-submersible floating offshore wind turbine(FOWT),a torus wave energy converter(WEC)and three flap-type WECs.The dynamic responses of the STFC with different semi-taut mooring configurations under operational and survival environmental conditions are assessed in terms of key performance parameters such as the platform’s motion responses and mooring line ten-sions.These performance parameters are compared against those of a chain-catenary mooring system.With the use of semi-taut mooring systems,significantly smaller mooring footprints as compared to the chain-catenary mooring systems can be achieved.Moreover,it is demonstrated that the semi-taut moor-ing systems are effective in reducing the maximum tension of the mooring lines.A basic cost analysis further indicates that semi-taut mooring systems offer substantial cost advantages over chain-catenary moorings in intermediate water depths.展开更多
基金Supported by the Specialized Research Project for LS17-2 Semi-submersible Production Platform(LSZX-2020-HN-05-0405).
文摘The taut mooring system using synthetic fiber ropes has overcome the shortcomings such as the large self-weight of the mooring lines and provides better mooring performance for the floating structures.The polyester rope has attracted much attention among numerous synthetic fiber rope materials due to its lightweight,low price,corrosion resistance,and high strength.Thus,the mooring characteristics of it are worth studying.Polyester mooring lines are flexible in deep water,when a marine structure is moored by them,the geometric nonlinearity such as large displacement,large stretch,and large bending deformation,and the material nonlinearity like viscoelastic of the polyester ropes become complex integrated problems to be studied.Considering the nonlinear phenomenon,the simulation and calculation of a polyester line were carried out by the absolute nodal coordinate formulation(ANCF)in this paper since the ANCF method has advantages in dealing with the significant deformation problems of the flexible structures.In addition,a chain mooring line was also simulated for comparison,and the results show that the polyester ropes reduce the self-weight of the mooring lines and provide sufficient mooring strength at the same time,and the nonlinear phenomenon of the polyester ropes is different from that of the chain mooring lines.
基金supported by the National Natural Science Foundation of China(Grant No.51879047).
文摘The dynamic stiffness of polyester rope presents a complex mechanical performance,and the search for an appropriate calculation method to simulate this property is important.Distorted simulation results eventually yield inaccurate line tension and vessel offset predictions,with the inaccuracy of vessel offset being particularly large.This paper proposes a flexible calculation method for the dynamic behavior of polyester rope based on the dynamic stiffness model.A real-time varying stiffness model of polyester rope is employed to simulate tension response through rope strain monitoring.Consequently,a simulation program is developed,and related case studies are conducted to explore the differences between the proposed method and analytical procedure of the DNV standard.Orcaflex is used to simulate the results of the latter procedure for comparison.Results show the convenience and straightforwardness of the procedure in the selection of an approximate dynamic stiffness model for polyester rope,which leads to an engineering-oriented approach.However,the proposed method is related to line property,which can directly reflect the dynamic behavior of polyester rope.Thus,a flexible calculation method may provide a reference for the simulation of the dynamic response of polyester mooring systems.
文摘For intermediate water depths(typically ranging from 50 m to 80 m),designing steel catenary mooring systems for floating marine renewable energy(FMRE)platforms can be challenging due to the limited weight of suspended mooring lines.This can substantially increase mooring line tensions following large platform offsets.In contrast,mooring systems using synthetic fibre ropes offer the potential to prevent large platform offsets while reducing peak mooring line tensions.In this study,novel semi-taut moor-ing systems incorporating polyester ropes and steel chains are proposed for a combined wind and wave energy system-the semi-submersible flap torus combination(STFC)concept,deployed at a 50 m wa-ter depth.The STFC integrates a semi-submersible floating offshore wind turbine(FOWT),a torus wave energy converter(WEC)and three flap-type WECs.The dynamic responses of the STFC with different semi-taut mooring configurations under operational and survival environmental conditions are assessed in terms of key performance parameters such as the platform’s motion responses and mooring line ten-sions.These performance parameters are compared against those of a chain-catenary mooring system.With the use of semi-taut mooring systems,significantly smaller mooring footprints as compared to the chain-catenary mooring systems can be achieved.Moreover,it is demonstrated that the semi-taut moor-ing systems are effective in reducing the maximum tension of the mooring lines.A basic cost analysis further indicates that semi-taut mooring systems offer substantial cost advantages over chain-catenary moorings in intermediate water depths.
