冰激振动下海洋平台动力响应与安全性分析

发布时间：2018-09-14 14:15

【摘要】：随着社会工业化的快速发展和人们物质生活水平的不断提高,石油等自然资源的消耗逐渐增多,日益增长的石油需求与逐渐枯竭的陆地石油之间的矛盾迫使人们将目光投向海洋。海洋石油储量丰富,多数集中在大陆架上,具有巨大的开发前景。用来开采海洋石油的海上油气平台,被称为海洋平台。相较陆地设施来说,海洋平台具有自然环境恶劣、空间狭小、投资大、技术要求高等特点,海洋平台压力容器泄露、平台倒塌、火灾爆炸等事故的发生将会造成巨大的财产损失和人员伤亡,海洋平台安全事故的高风险性和高危害性致使其需要更加完善的安全措施。针对海洋平台自然环境恶劣的特点,选取目前在我国渤海及黄海海域成为控制载荷的冰载荷,进行冰激振动下海洋平台的动力响应和安全性分析,具有一定的工程意义。从海冰力学性质、海冰破坏类型和冰激振动理论三方面入手,简要分析海冰的力学性质,针对海冰的破坏类型给出挤压、弯曲和屈区状态下冰力的计算公式,对比三种冰激振动理论,为分析海洋平台动力响应提供理论基础。总结静冰力的完全经验公式和半经验半理论公式,建立动冰力函数模型,根据海洋平台环境参数测算冰力遮蔽效应以及平台阻尼,为海洋平台环境载荷提供了计算方法。采用ANSYS软件建立海洋平台模型,对冰激振动下海洋平台的动力响应进行数值模拟,得到海洋平台的振型图以及极端冰工况下海洋平台的动力响应参数。加载不同冰速、冰厚下海洋平台的载荷参数,对比分析不同冰速与冰厚对平台动力响应的影响。模拟分析的结果为海洋平台安全性分析提供数据支持。根据模拟分析数据对海洋平台进行安全性分析,建立海洋平台的可靠性模型,计算海洋平台冰振下的疲劳寿命,并采用道化学火灾爆炸危险指数评价法对平台的火灾爆炸危险性以及危害后果进行评价,针对极端冰工况下海洋平台的安全补偿系数进行一定的修正。
[Abstract]:With the rapid development of social industrialization and the continuous improvement of people's material living standard, the consumption of natural resources such as oil is gradually increasing. The conflict between growing oil demand and dwindling land oil forces people to look to the sea. The offshore oil reserves are abundant, most of them are concentrated on the continental shelf. Offshore oil and gas platforms used to exploit offshore oil are called offshore platforms. Compared with land facilities, offshore platforms are characterized by poor natural environment, narrow space, large investment, high technical requirements, leakage of pressure vessels and collapse of platforms. Accidents such as fire and explosion will cause huge property losses and casualties. The high risk and harm of offshore platform safety accidents lead to the need for more perfect safety measures. In view of the bad natural environment of offshore platform, it is of engineering significance to select the ice load which is used to control the load in Bohai Sea and Huang Hai Sea area of China, and to analyze the dynamic response and safety of offshore platform under ice-induced vibration. Starting with the mechanical properties of sea ice, the types of sea ice failure and the theory of ice induced vibration, the mechanical properties of sea ice are briefly analyzed, and the calculation formulas of ice force in the state of compression, bending and bending are given for the failure type of sea ice. The comparison of three ice-induced vibration theories provides a theoretical basis for analyzing the dynamic response of offshore platforms. The complete empirical formula and semi-empirical semi-theoretical formula of static ice force are summarized, and the dynamic ice force function model is established. The ice force shielding effect and platform damping are calculated according to the environmental parameters of the offshore platform, which provides a calculation method for the environmental load of the offshore platform. The dynamic response of offshore platform under ice-induced vibration is numerically simulated by using ANSYS software. The vibration pattern of offshore platform and the dynamic response parameters of offshore platform under extreme ice condition are obtained. The influence of different ice velocity and thickness on the dynamic response of the platform is analyzed by comparing the loading parameters of the offshore platform under different ice speeds and ice thickness. The results of simulation analysis provide data support for offshore platform safety analysis. According to the data of simulation analysis, the safety of offshore platform is analyzed, the reliability model of offshore platform is established, and the fatigue life of offshore platform under ice vibration is calculated. The fire and explosion hazard and its consequences of the platform are evaluated by the chemical fire explosion risk index evaluation method, and the safety compensation coefficient of the offshore platform under extreme ice condition is modified to a certain extent.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE95

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