裂纹损伤下导管架平台剩余强度研究

发布时间：2018-04-04 16:06

本文选题：导管架平台　切入点：裂纹损伤　出处：《江苏科技大学》2015年硕士论文

【摘要】：海洋平台作为海洋石油勘探开发的主要工作和生活场所,目前世界上已有一百多个国家和地区从事海洋油气的勘探、开发。平台长期服役在恶劣的海洋环境中,腐蚀、疲劳裂纹是最为常见的平台结构损伤类型,不仅造成平台结构整体抵抗力的降低,而且威胁着石油资源的利用、海洋环境的保护和人员生命的保障,国内外历次发生的平台倾覆事故,不仅造成经济上的损失,对于作业人员的生命安全和海洋环境都会产生巨大的影响。因此,在役海洋平台结构的性能评估成为备受关注的问题,而损伤结构的剩余强度研究则是结构性能评估的关键内容。由于导管架平台主要用作采油平台,固定在海水中服役数十年之久,不可避免的会产生裂纹,加之检测维修困难,裂纹将对平台的极限承载力产生重大影响。本文即以导管架平台为例,分析裂纹损伤对导管架平台结构极限强度的影响。具体研究工作如下:1、阐述了对受损后的海洋结构物进行极限强度研究的现状,详细介绍了关于结构极限强度的计算方法。2、阐述了基于断裂力学原理的疲劳裂纹扩展方法和结构非线性行为的研究方法,引入多尺度有限元原理,并介绍多尺度模型的构建方法和计算方法。3、根据平台的结构形式和环境载荷,得到平台在工况下的热点位置,同时基于断裂力学扩展原理确定时变裂纹尺寸,并对比分析多尺度有限元法在分析结构极限强度时的适用性和可行性,为分析带裂纹损伤的大型海洋结构物的非线性行为创造了条件。4、建立了时变裂纹损伤下的导管架平台多尺度模型,考察了环境荷载下,裂纹尺寸、焊缝和腐蚀壁厚等因素对平台剩余寿命的影响。5、建立了时变裂纹损伤下的导管架平台多尺度模型,得到平台在时变裂纹损伤下,剩余强度的变化规律。选择裂纹损伤对平台整体承载力影响较大的区域为分析对象,分析了单一节点含裂纹损伤下,裂纹尺寸、腐蚀壁厚和焊缝等因素对平台剩余强度的影响;并对多节点裂纹损伤下海洋平台结构的剩余强度进行研究。
[Abstract]:Offshore platform is the main work and living place of offshore oil exploration and development. At present, more than 100 countries and regions in the world are engaged in the exploration and development of offshore oil and gas.Corrosion and fatigue crack are the most common damage types of platform structure, which not only reduce the overall resistance of platform structure, but also threaten the utilization of petroleum resources.The protection of marine environment and the protection of human life, and the accidents of overturning platforms at home and abroad, not only cause economic losses, but also have a great impact on the safety of operators and marine environment.Therefore, the performance evaluation of existing offshore platform structures has become a major concern, and the residual strength of damaged structures is the key content of structural performance evaluation.Because jacket platform is mainly used as oil recovery platform, fixed in seawater for decades, it will inevitably produce cracks, and the crack will have a significant impact on the ultimate bearing capacity of the platform.In this paper, the influence of crack damage on the ultimate strength of jacket platform is analyzed.The specific research work is as follows: 1. The current situation of studying the ultimate strength of damaged marine structures is expounded.The calculation method of ultimate strength of structure is introduced in detail. The fatigue crack propagation method based on fracture mechanics and the research method of nonlinear behavior of structure are expounded. The multi-scale finite element principle is introduced.The construction method and calculation method of the multi-scale model are introduced. According to the structural form of the platform and the environmental load, the hot spot of the platform under the working condition is obtained. At the same time, the time-varying crack size is determined based on the propagation principle of fracture mechanics.The applicability and feasibility of the multi-scale finite element method in the analysis of the ultimate strength of the structure are compared and analyzed.In order to analyze the nonlinear behavior of large ocean structures with crack damage, conditions .4. the multi-scale model of jacket platform under time-varying crack damage is established, and the crack size under environmental load is investigated.The influence of weld and corrosion wall thickness on the residual life of the platform. 5. The multi-scale model of jacket platform with time-varying crack damage is established, and the variation law of residual strength of the platform under time-varying crack damage is obtained.The influence of crack size, corrosion wall thickness and weld seam on the residual strength of the platform is analyzed by selecting the area where the crack damage has a great impact on the overall bearing capacity of the platform, and the influence of crack size, corrosion wall thickness and weld seam on the residual strength of the platform is analyzed under the single joint crack damage.The residual strength of offshore platform structures under multi-node crack damage is studied.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U674.38

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