计及与托管架和海床接触耦合效应的深海管道S型铺设整体动力特性研究

With the exploitation of offshore oil and gas into deep-sea regions, the dynamic characteristics and laying safety of oil-gas pipeline become one of the key factors for the offshore engineering. Due to the dynamic contact with the stinger and the seabed, the stress and strain response of the pipeline during installation is significant, which usually causes engineering accidents of pipeline local buckling. Thus, it is extremely important to accurately evaluate the dynamic characteristics of the pipeline considering the contact coupling effect. In this project, the combined means of theoretical analysis, model experiment and program development based on vector form intrinsic finite element method are applied. In the contact coupling boundary, the relational expressions of the contact boundary conditions with time-varying three-dimensional space force system are investigated to realize the valid simulation of the non-linear mechanical behavior of the pipeline contact coupling with the stinger and the seabed. In the aspect of deep-sea loads, the reasonable representation modes of environmental loads and pipelay vessel motions are established. Moreover, the multi-scale coupling model and numerical algorithm are built for large scale structure with beam-shell element of laying pipeline, and the GPU parallel technique is adopt to accelerate the calculation process. On structure response, the present study aims to investigate the global dynamic characteristic of the pipeline during deep-sea S-lay process, and clarify the local deformation feature of the pipeline in the contact coupling part, and reveal the contact coupling mechanism of the pipeline with the stinger and the seabed, and ascertain the influence of contact coupling on the internal force and deformation of laying pipeline. The research findings lay a solid theoretical foundation for the design and the safety monitoring of pipeline installation.

随着海洋油气开发迈向深海，管道铺设动力特性与安全成为海洋工程研究的重点之一。铺管过程管道与托管架及海床动力接触碰撞，应力应变响应显著，常会遭遇局部屈曲等工程事故，准确评估计及接触耦合效应的管道动力特性显得尤为重要。项目拟基于向量式有限元方法，通过理论分析、模型试验和程序开发等手段，在接触耦合边界，探索具有时变特性三维空间力系接触边界条件的表达关系，实现管道与托管架及海床接触耦合非线性力学行为的有效模拟；荷载层面，构建深海环境荷载及铺管船运动激励作用的合理表征模式；多尺度算法层面，探究铺设管道大尺度细长结构匹配梁-壳单元多尺度耦合算法，实现GPU并行技术计算加速；结构响应层面，探究深海管道S型铺设整体动力特性，阐明接触部位管道局部变形特征，揭示管道与托管架及海床接触耦合作用机制，探明系统接触耦合动力效应对铺设管道内力与变形响应的影响规律，为管道铺设设计与施工安全监测奠定坚实的理论基础。

随着海洋油气开发迈向深海，管道铺设动力特性与安全越来越受到关注。深海铺管过程管道与托管架及海床动力接触碰撞，应力应变响应显著，给铺管设计带来极大挑战。项目基于向量式有限元方法，通过理论分析、模型试验和程序开发等手段，建立深海管道S型铺设整体时域模型，实现管道与托管架及海床土接触耦合非线性力学行为的准确识别及有效模拟，进行深海管道铺设非线性时域模拟分析，研究发现随机波浪、海流及铺管船运动作用下管道动力响应显著，最大响应发生在管道与托管架接触末端滚轮位置；探究铺管参数铺设水深、张紧器张力、托管架长度、管道直径与浮重度对管道动力性能的影响，明确影响管道动力响应的重要因子，通过优化铺管参数可以有效减小管道的动力响应；采用极限波与随机波组合模型模拟生成畸形波序列，实现畸形波作用下深海铺设管道动力模拟，探明畸形波特征参数对管道动力性能的影响；提出双层管等效计算模型，研究深海双层管S型铺设动力响应及其影响因素,结果表明外管主要承担张力和弯矩以及外部荷载作用，会产生较大的应力与应变响应，而内管的受力与变形响应相对较小。研究结果可为深海管道铺设设计与施工安全监测奠定坚实理论基础。. 深海铺设管道是细长悬链线结构，项目建立的铺管动力计算理论与分析方法可以扩展到深海J型铺管、深海立管、锚泊系统等海洋细长结构的计算分析，同时通过计算程序模块的改进，研究成果可快速应用工程实践，对探明海洋细长结构的动力特性具有重要科学意义和应用价值。