含缺陷海底管道非线性流固耦合振动的理论与实验研究

Submarine pipeline is the most important means of transportation in the offshore oil industry. Due to the extreme environment, submarine pipelines always subject to various defects, which poses great threats to the structural reliability and the safety of transportation. The main contents of this project include: to analyze theoretically the vortex induced vibration (VIV) of multi-layered submarine oil pipelines with local corrosion pits, large-area erosion, or imperfect interfacial bonding; to establish nonlinear fluid-structure interaction models based on the 3D Euler-Bernoulli beam theory or the elasticity theory of hollow cylinder with nonhomogeneous thickness or imperfect interface, to investigate the effects of pits, erosion, imperfect bonding on the VIV of the pipelines; and to study the local vibration characteristics of the large-area erosion on the pipeline. Laboratory experiments and on-site tests in real ocean environment will be conducted, and the direct numerical simulations (DNS) will also be performed. The aims of this project are to propose theoretical models for the VIV of submarine pipelines with defects so that their dynamics behavior is predicted effectively, and to explore the underlying affecting mechanism of defects on the dynamics behavior of submarine pipelines. This project will exhibit its scientific significance in the aspect that it may pave the base for the completeness of the theoretical models for fluid-structure interaction of submarine oil pipelines. In addition, the outcomes of this project may also render references for the reliability evaluation,repair and vibration control of submarine oil pipelines with defects, and, therefore, have a promising future in engineering applications.

海底管道是海洋石油工业中最重要的运输手段，其工作环境极端，在服役过程中容易出现缺陷损伤，对结构可靠性和输运安全造成了极大威胁。本项目拟针对含局部蚀坑、管壁大面积剥蚀、或弱界面缺陷的层状海底输油管道涡激振动开展理论研究，分别建立变刚度三维梁、变厚度和弱界面层状空心圆柱壳的非线性流固耦合振动模型，考察蚀坑缺陷形态、剥蚀深度和范围、弱界面刚度对输油管道涡激振动的影响规律，并研究含大面积剥蚀缺陷管道的局部振动特性。同时进行室内实验和真实海洋环境下的现场试验研究，并开展同时针对流场与结构的三维数值仿真。通过本项目的研究，旨在建立合理有效的含缺陷海底输油管道涡激振动理论模型，再现其实际工作性状，明确缺陷对管道动力特性的影响机制，从而为完善输流管道流固耦合振动的理论体系奠定基础，具有重要的科学意义，同时可为海底管道出现缺陷后的安全评估、维修加固和振动控制提供决策依据，具有重要的现实意义和广阔的应用前景。

项目针对含缺陷海底管道涡激振动开展理论研究，分别基于梁理论和三维全场流固耦合理论，建立了考虑流固耦合效应的管道振动计算方法，开展了同时针对流场与结构的三维数值仿真，并基于实验数据对所提理论方法进行了验证。基于结构振动计算基础理论，分别建立了变刚度三维梁、变厚度和弱界面层状空心圆柱壳的非线性流固耦合振动模型，考察了裂纹、蚀坑、层间弱界面三种典型缺陷对海底管道涡激振动的影响规律及机制，完成了申请书所提研究内容。在基金申请书计划内容的基础上，针对海底管道涡激振动致管道损伤的隐患，提出了对应的管道振动控制方法，采用三维全场流固耦合理论结合有限元方法对管道振动控制开展了理论研究，获得了整流罩和分隔板两种振动控制装置的尺寸优化方案。并针对海底服役管道振动状态的评估需求，基于静电发电原理研发了适用于海底管道的自供能智能感知技术，对海底管道的振动状态评估提供一种新型智能感知方法，为管道的运营评估提供依据和技术支持。以上研究成果完成了基金申请书计划内容，并根据实际工程应用需求开展了延续性探索，取得了良好进展。依托本项目，共指导博士研究生3名、硕士研究生9名，其中毕业博士生1名、硕士生3名。课题组晋升副教授2名，晋升博士生导师2名，博士后出站1名。在本项目实施期间，项目组成员参与了多次国际交流合作，参与筹备组织第四届全国海洋技术会议暨OceanTech International Symposium，并参与国内外会议或学术交流并进行主题或邀请报告18人/次，其中国际12人/次，国内6人/次。项目相关成果以论文形式发表共计SCI论文8篇，授权软件著作权3项，授权专利16项，公开专利19项。