深水半潜式平台结构关键节点的疲劳损伤机理与寿命预测研究

项目名称： 深水半潜式平台结构关键节点的疲劳损伤机理与寿命预测研究

项目编号： No.51509221

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 其他

项目作者： 崔磊

作者单位： 浙江大学宁波理工学院

项目金额： 20万元

中文摘要： 深水半潜式平台结构在深海环境荷载和作业动荷载的作用下容易产生疲劳损伤累积，加速疲劳裂纹的扩展，导致结构发生疲劳破坏。本项目首先分析深海不同工况下半潜式平台结构的应力响应，确定半潜式平台结构疲劳关键部位，考虑深海环境下半潜式平台结构关键部位服役时的受力状态，研究平台结构疲劳关键部位的失效模式；在此基础上，探索深水半潜式平台结构关键部位的疲劳损伤断裂机理，考虑应力水平、加载次序和频率对关键节点疲劳寿命的影响，建立平台关键节点的疲劳损伤断裂理论模型；研究疲劳断口不同裂纹扩展区域的微观组织结构，揭示疲劳裂纹扩展速率、裂纹扩展方向及疲劳破坏机理，阐明关键节点从疲劳累积损伤到疲劳裂纹扩展直至迅速断裂整个过程的规律和本质，建立深水半潜式平台关键节点的疲劳寿命预测模型。为有效地预测结构的疲劳损伤程度，及时地对结构进行维修加固，延长结构的使用寿命，避免平台发生疲劳事故，确保平台安全可靠运行，提供科学依据。

中文关键词： 半潜式平台；疲劳损伤；寿命预测

英文摘要： Deepwater semi-submersible platform structures under the load of deep-sea environment and operating will generate fatigue damage accumulation, which accelerates the expansion of fatigue crack and causes the fatigue failure of platform structures. First of all, the stress responses of the platform under different deep-sea states will be analyzed to determine the fatigue crucial structures in this project. Failure modes of the fatigue crucial structures will be studied by considering the stress states of the crucial structures in serving under deep-sea environment. And then, on the basis of analysis results, the fatigue damage-fracture mechanism of semi-submersible platform structures will be explored. Considering the influence on the fatigue life of crucial structures by stress level, loading sequence and frequency, the theoretical model of the platform fatigue crucial structures will be established. Finally, the microstructures of different regions in fatigue fractures are analyzed to reveal the fatigue crack growth rates, directions and the fatigue failure mechanism, clarify the law and nature of crucial structures from fatigue cumulative damage to fatigue crack propagation until rapidly breaking. Based on the analysis above, the fatigue life prediction model of deepwater semi-submersible platform crucial structures will be established. It will provide a scientific basis for the effective prediction of fatigue damage degree, maintenance and reinforcement the structures in time, extending the service life of crucial structures, avoiding the fatigue accidents and ensuring the safe and reliable operation of the platform.

英文关键词： semi-submersible platform ;fatigue damage ;life prediction