Abstract Soft yoke mooring system (SYMs) is a single-point mooring system used in shallow water oil and gas development. In general, SYMs consists of mooring framework support, mooring legs, yoke, and single-point turret and it forms a multibody dynamic system with 13 hinge joint structures such as universal joints and thrust bearings. The hinge joint is one of the key components of SYMs; therefore, it is necessary to accurately evaluate the operating behavior of the hinge joints. In this study, real-time damage identification is conducted based on the multibody dynamic features of the SYMs. First, a long-term monitoring strategy for the prototype application is developed based on the multibody governing equations of the SYMs. The motion behaviors and stress state of the hinge joints and bodies are calculated using prototype monitoring data. A hinge joint damage identification based on the virtual moment is proposed by considering the changes in the friction coefficient in the damage state. The virtual moment method is used to transform the damage identification problem of the SYMs into a problem of seeking the optimal solution to the dynamics identification function. Genetic algorithm (GA) is implemented to seek the optimal solution of the friction coefficient of each hinge joint. A large-scale model testing system of the SYMs is established to perform the damage identification of the bottom hinge joints of the SYMs. The results show that the proposed method can effectively identify the damage degree and position of the hinge joints of the SYMs and provide a real-time warning system for the in-service operation of the SYMs.

中文翻译：

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基于多体动力学建模和结构监测数据的软轭系泊系统铰链损伤识别方法

摘要 软轭系泊系统（SYMs）是一种用于浅水油气开发的单点系泊系统。SYMs一般由系泊框架支架、系泊腿、轭架和单点转塔组成，由万向节、推力轴承等13个铰链关节结构组成多体动力系统。铰链是SYMs的关键部件之一；因此，有必要准确评估铰链接头的操作行为。在本研究中，基于 SYM 的多体动力学特征进行实时损伤识别。首先，基于 SYM 的多体控制方程开发了原型应用的长期监控策略。使用原型监测数据计算铰链关节和主体的运动行为和应力状态。考虑损伤状态下摩擦系数的变化，提出了一种基于虚拟力矩的铰接头损伤识别方法。利用虚矩法将SYMs的损伤识别问题转化为动力学识别函数的最优解问题。实施遗传算法（GA）以寻求每个铰链关节摩擦系数的最优解。建立了SYMs大型模型试验系统，对SYMs底部铰接节点进行损伤识别。结果表明，该方法能够有效识别SYMs铰链接头的损伤程度和位置，为SYMs在役运行提供实时预警系统。