内转塔单点系泊刚度对不同参数的敏感性分析

Sensitivity analysis of different parameters for the stiffness of internal turret mooring systems

内转塔式单点系泊系统在海洋石油装备中得到广泛应用。为研究该类型单点系泊系统的刚度特性,以我国南海一艘内转塔式单点系泊浮式生产储油设备(FPSO)的系泊系统为研究对象,采用浮体系泊分析软件Ariane分别建立单根系缆和系泊系统的静力分析模型,基于线弹性悬链线理论计算单根系缆和系泊系统的刚度,并重点针对吃水、系缆轴向拉伸刚度、系缆配重、系缆长度等参数进行系泊刚度敏感性分析,研究不同参数变化对系泊刚度的影响。结果表明:系泊刚度对系缆长度变化十分敏感;吃水和系缆长度主要通过影响系缆预张力来影响系泊刚度;系缆轴向拉伸刚度主要影响大位移条件下的系泊刚度;配重只影响一定位移范围内的系泊刚度。最后,给出了单点系泊系统设计的建议。

Internal turret Single Point Mooring （SPM） systems are widely used for positioning Floating Production, Storage and Offloading（FPSO） vessel in South China Sea. In order to analyze the stiffness characteristic of such SPM systems, both the static single-line model and mooring system model are established using the mooring design software Ariane. Based on the linear elastic catenary theory, the stiffness of a single line and the whole mooring system are calculated. The sensitivity of the mooring system＇s stiffness is studied by changing several design parameters such as the draft of FPSO, the clump weight on the mooring line, and the length and axial tensile stiffness of the mooring line. It is observed that the mooring stiffness is rather sensitive to the length of the mooring line due to the change of the initial tension in the line; the effect of axial tensile stiffness cannot be neglected under the condition of large displacement on the upper end of the mooring line; clump weight affects mooring stiffness within a certain displacement range. Finally, certain suggestions are put forward for the design of the mooring system.