热-流-固三场耦合作用下悬跨海底管道动力响应和屈曲研究

According to the major strategy on the technique of Oil &Gas exploration and development in deep water, this project focuses on the vibration and dynamic buckling of free spanning submarine pipeline with high temperature, high pressure, conveying fluid and fluid outside. Based on the research experience on impact dynamics and Fluid Structure Interaction, the dynamic response and buckling of free spanning submarine pipeline are investigated. The temperature field and the effects of conveying fluid and fluid outside are mathematically descripted precisely. Considering the deflection and vibration characteristics of pipeline varying by load, geometry and materials, 1D/3D—Linear/Nonlinear methods are developed for the dynamic response and buckling of free spanning submarine pipeline. Combining all the methods, an analytical methodology for dynamic response and buckling are proposed. Based on the fluid similarity criterion and structure similarity criterion, an experiment setup considering the conveying fluid, fluid outside and temperature loads are proposed for the dynamic response and buckling. The analytical methodology proposed is validated by comparison with experiment results. By employing analytical methods, numerical methods and experiments, the effects of various factors on the linear and nonlinear free vibration characteristics, force vibration characteristics and dynamic buckling characteristics are investigated. The interaction mechanism between thermo-hydro-mechanical field and the combined action of thermo-hydro-mechanical field on dynamic response and buckling are analyzed. The research provides a scientific basis and theory foundation for the safety assessment for vibration and dynamic stability of free spanning submarine pipeline.

本项目围绕国家在深水油气勘探开发技术的重大战略需求，聚焦内、外流作用下高温高压海底管道的振动与动力屈曲问题。基于申请人及课题组在结构冲击动力学和流固耦合等领域的研究基础，对管道的温度场、内流和外流进行准确的数学描述，结合不同荷载、几何和材料特性条件下的结构变形和振动特性，提出热-流-固三场耦合作用下海底管道悬跨段的一维/三维—线性/非线性动力响应和动力屈曲计算方法，形成一套解析求解体系，并与数值模拟结果相互验证。基于流体和结构相似准则，建立一套考虑温度荷载和内、外流的海底管道悬跨段动力响应试验方案，验证解析计算体系。综合利用解析、数值和试验等多种手段，深入分析各方面因素对于悬跨段线性和非线性自振特性、激振特性和动力屈曲的影响，揭示热-流-固多物理场相互作用机理，探明热-流-固三场对于管道动力响应和动力屈曲的共同作用机制，为高温高压海底管道的振动和动力稳定性安全评估提供理论基础和科学依据。

海洋工程结构是海洋资源可持续开发利用的重要载体，保障其安全具有重要意义。在风浪流等海洋环境荷载作用下，结构动力响应特别是振动往往会造成节点等结构关键部位疲劳、损伤、断裂和破坏等。因此，海洋环境荷载作用下结构振动是当前的研究热点，而水下复合结构的流固耦合振动更是受到高度关注。在研究方法中，理论研究能够更精细地诠释其内在机理、并往往作为成果相互验证的基准，是一项基础性的研究工作，具有重要的科学价值。研究中首次提出了任意边界条件下的复合板瞬态响应三维半解析方法。该方法通过微分求积（DQM）这一高效处理初值和边值问题的数值技巧，解决了传统的状态空间方法只能处理简支边界条件的局限，可以在每一个离散点上精确地处理边界条件，因此能够解决多场（热荷载等）耦合荷载作用下复杂几何形状和边界条件下梁、板、壳的瞬态响应。同时研究首次提出了任意边界条件下的功能梯度层合压电结构瞬态响应三维半解析求解方法。基于上述状态空间-精细积分-数值Laplace逆变换-DQM”求解体系，建立了力电耦合半解析三维求解方法，填补了压电复合结构在不同边界条件下动力学行为解析领域的空白。在对结构线性振动和非线性动力行为研究基础上，研究提出了一种数值时滞传递熵与替代数据算法相结合的损伤识别技术，可以在不使用未损伤结构振动基准数据的条件下，对具有损伤的梁、板和圆柱壳结构的振动数据进行非线性识别，从而实现损伤识别。创新性成果为海洋结构的振动和动力稳定性安全评估提供理论基础和科学依据，可用于指导海洋结构设计、施工和运行管理，有利于完善海洋结构物振动理论体系，具有重要的理论意义和工程价值。