【作者】 乐丛欢；

【导师】 丁红岩；

【作者基本信息】 天津大学 ， 建筑工程技术与管理， 2010， 博士

【摘要】 海洋平台在复杂恶劣的环境中工作,除正常的工作荷载、环境荷载的作用外,还受到偶然荷载威胁,如船舶的撞击、平台上部落物的撞击。偶然荷载引发的事故不但会造成人员伤亡和重大的经济损失,而且会对近海周边环境和海洋生态造成严重的污染和破坏。在我国工程应用领域中,海洋平台风险评估工作开展相对较少,现有海洋平台设计,大多没考虑到偶然荷载的作用,通常的做法是在平台交付使用后再进行修改,这样势必造成人力和财力浪费。因此对平台进行偶然荷载作用下的风险评估十分必要。但是,对于刚刚兴起不久海洋工程领域,关于海洋平台风险的统计数据很少,这给风险定量计算带来了很大的困难。另外就由碰撞引起的海洋结构损伤分析本身而言,其力学机理复杂,再加上海洋环境复杂,开展试验研究的成本过高,且不确定因素颇多,在这种情况下有限元数值仿真在碰撞分析领域越来越受到重视。本文是在中海石油(中国)有限公司委托的《LD32-2PSP定量指数评价及重大危险源辨识安全分析》项目的基础上展开的。研究注重理论与工程实践相结合,在较深入研究风险分析理论及平台结构碰撞损伤的基础上,对海洋平台碰撞风险建立定量评估系统。以实现海洋平台的风险预测由传统经验型向科学预测型转变。本文的主要内容和研究成果包括如下几点:1.大量查阅国内外文献,了解分析国内外海洋结构物碰撞风险评估的研究现状,探究各种风险分析方法的适用范围及优缺点,为海洋平台碰撞风险分析奠定基础。2.对海洋平台结构物碰撞损伤经验公式法、能量法和有限元法进行介绍。建立LD32-2PSP平台结构显式动态有限元模型,系统分析吊机落物引起的平台结构甲板设备以及海底管线的损伤。计算分析船舶以不同的速度撞击平台结构及立管引起的结构动力响应,对平台整体结构的损伤程度进行了评估。3.结合风险评估方法,建立海洋平台在偶然荷载作用下的风险分析框架。根据偶然灾害的发生概率和平台暴露级别来划分灾害事件的风险水平,并依据风险水平结合LD32-2PSP平台结构开展定量风险评估,在对落物碰撞风险、船舶撞击风险的发生频率,结构损伤程度加以分析判断的基础上完成了平台落物风险和船舶撞击风险的定量评估,为保障海洋平台结构在偶然灾害下的整体安全性提供了分析方法和理论依据。4.在风险评估的基础上,提出了降低落物风险和船舶撞击风险的措施。更多还原

【Abstract】 Offshore platforms work in complex and harsh environments, in addition to normal work load, environment loads, also threatened by accidental loads, such as the impact of ships, impact of dropped objects. Major disaster caused by accidental loading will not only result in casualties and major economic losses, but also the surrounding coastal environment and marine ecosystem caused by pollution and destruction. The offshore platform risk assessment carried out relatively small In Engineering applications of China, the current offshore platform design, the accidental loads most did not take into account. The most common practice is to maintain after be delivery platform, it will certainly waste a lot of manpower and financial resources. So it is essential to analyze and assess the behaviors of platform subjected to the accidental loading. However, very little statistical data on the disaster of offshore platform for the nascent field of ocean engineering, it has made it difficult to Quantitate the risk, In addition to the complex mechanical mechanism of the ocean structures damage caused by the collision, coupled with the complexity of the marine environment, high cost of pilot studies, and does not identify many factors, in this case, finite element numerical simulation has more and more attention In the field of collision analysis.This paper started on the basis of the project of "LD32-2PSP quantitative index for assessing and recognizing the safety of major hazard" entrusted by China National Offshore Oil Corporation (CNOOC) (China) Co., Ltd. Research focus on combining theory and engineering practice, on the basis of the in-depth research on the risk analysis method and on structural collision damage, offshore platform collision risk quantitative assessment system to achieve the risk assessment of offshore platforms from the traditional experience to scientific prediction type. The main contents and findings include the following:1. Based on Searching and Reviewing a large number of both Domestic and foreign Literature high-risk industries research data, it is to analyze domestic and foreign marine structure impact of risk assessment status, and is to explore the various risk analysis methods and the advantages and disadvantages of the application for further risk quantitative assessment of offshore platform subjected to collision.2. The methods to analyze offshore platform structure collision damage are introduced, including the empirical formula, energy method and the finite element method. The finite element model of LD32-2 PSP Platform is established by explicit dynamic. Dynamic Response and damage of the offshore platforms structure, Deck equipment pipeline caused by falling objects. Dynamic Response and damage of the offshore structure and the riser due to the ship impact at different speeds, and the overall damage of the platform structure was assessed.3. The analysis framework of offshore platforms in the risk of accidental loads is established, using the risk assessment methods. According to the probability of accidental disasters and platform exposure level to divide the risk levels of disaster. The risk analysis of LD32-2PSP Platform was carried out according to the risk levels. The structural quantitative risk assessments from the falling objects and ship impacts are carried out based on the calculated risk of collision frequency and the extent analyzed Structural damage. The result can provide the analysis method and the theoretical basis for the protection the overall security of offshore platform structures in the occasional hazards.4. On the basis of risk assessment, measures are proposed to reduce the risk of falling objects and ship collision risk.更多还原