基于多体动力分析方法进行FPSO和水下软钢臂系泊系统的运动特性研究.相较于非线性弹簧模拟软钢臂系泊系统或者其他近似模拟方法,多体分析方法可以充分考虑系泊系统具体结构形式及其动力项对FPSO运动性能的影响,更好的预报系统运动响应和系泊力.本文将FPSO和水下钢臂结构模拟成2个具有6自由度的独立结构,两者用系泊链组进行连接.基于三维势流理论应用汇源分布法,首先在频域内进行FPSO的水动力参数分析,进而在时域内对系统进行耦合动力分析.本文重点讨论系泊系统黏性力和二阶波浪力对系统响应的影响,计算结果发现系泊系统黏性力对系泊力有一定影响,而在浅水条件下二阶波浪力的计算对准确预报系统运动及系泊力非常重要.%Multi-body dynamic simulation method is applied for coupled dynamic analysis of a FPSO (Floating Production Storage and Offloading) with the underwater soft yoke SPM (single point mooring) system. Comparing with the method simulating soft yoke mooring system by non-linear spring or other approximate ones, the multi-body method could take into account the effect on FPSO motion response from the actual structure of the mooring system and its dynamic factors. Thus the motion response and mooring force of the system could be better predicted. In this analysis, the FPSO and underwater soft yoke, connected with each other through a pair of mooring lines, are modeled as two rigid bodies of six degrees. Based on three-dimensional potential theory using a distribution of singularities over the surface of the body, the hydrodynamic coefficients of the FPSO are calculated in the frequency domain, and in the time domain, the coupled dynamic analysis of the system is carried out. The effect of viscous force of the mooring system and the second order wave force on the system response is well investigated. There is some contribution to mooring force from the mooring system viscous force, and it is important to calculate the second order wave force for predicting the system response and mooring force under the shallow water.
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