海洋平台结构中K型管节点疲劳强度分析

【作者】 梁园华；

【导师】 郑云龙； 洪明；

【作者基本信息】 大连理工大学 ， 船舶与海洋结构物设计制造， 2002， 硕士

【摘要】 管节点是平台结构关键的部位，同时也是最薄弱的环节，海上平台的失事很多都是由于管节点脆性断裂或疲劳破坏所致，因此，对管节点的进行疲劳研究以探明其应力成分的形成机理，有效减小其应力集中，从而增加其疲劳寿命就显得特别重要。 本文的主要工作，就是对BING09000型半潜式平台的K型管节点进行了疲劳强度分析，为今后对海洋平台管节点疲劳强度的进一步研究打下基础。 首先，建立了BING09000半潜式平台的整体模型并对其进行了整体强度分析，然后根据DNV规范的要求对其进行了强度校核。这是进行其上局部K型管节点疲劳强度分析的前提。 然后，在建立的平台整体三维有限元模型基础上，结合北海波浪长期分布资料，计算了72种波浪载荷工况下的整体结构应力，为管节点结构局部应力分析提供边界条件。然后对管节点进行了疲劳强度分析。在计算管节点结构应力范围时，应用了广泛使用的热点应力法，并根据DNV规范提供的S-N曲线，以及Miner线性疲劳累积损伤准则计算出管节点结构的疲劳寿命。 最后，得出了平台遭受横浪时，K节点的疲劳损伤度要比遭受其它浪向时大得多以及构件弯曲是引起应力集中的主要因素等具有实际工程意义的结论。更多还原

【Abstract】 The tubular joints are the most important but the weakest members of ocean platform. It has been found that tubular joints fatigue cracks are a dominating type of damage in ocean platform, and the economical losses are also considerable. So it is evident that there is a great need for better understanding of tubular joints fatigue behaviors and mechanisms, thus the fatigue lifetimes of tubular joints can be correctly predicted and the effective ways to improve fatigue lifetimes can be found out.The main work of this thesis is to predict the fatigue lifetime of a K-joint in BINGO9000 ocean rig, and do some basic work for the further study of tubular joints fatigue lifetime prediction in future.Firstly, based on the DNV rules, a 3D finite element model of the rig was developed for stress calculation and the strength of structure was checked. To obtain the local stress distribution of the K-tubular joint, sub-model was built and calculated.Then, according to wave long-term distribution of North Sea, stresses of the whole structure subjected to 72 wave loads cases are calculated, which supplies boundary conditions of local tubular joint models in local stress analysis. Then, the fatigue strength analysis of K-joint is carried out. Hot spot stress method is used in the calculation of stress range. With S-N curve selected from DNV rules of fatigue strength analysis for mobile offshore unites, The Miner linear fatigue damage accumulation rule is used to calculate fatigue life of the tubular joints.Finally, some useful conclusions have been drawn, which will give valuable technical support for future design and building of the semi-submersible rig in China.更多还原