以3000 m J-Lay型深水铺管船作业为研究对象,建立全耦合数值分析模型。通过准静态分析研究立管敏感性参数变化规律,确定铺管作业时最优立管顶端倾角。考虑剖面流、风和波浪综合作用,对不同工况下铺管作业过程进行数值模拟,对铺管作业过...以3000 m J-Lay型深水铺管船作业为研究对象,建立全耦合数值分析模型。通过准静态分析研究立管敏感性参数变化规律,确定铺管作业时最优立管顶端倾角。考虑剖面流、风和波浪综合作用,对不同工况下铺管作业过程进行数值模拟,对铺管作业过程中立管受力特征、顶端固定点运动状态进行预报和研究。研究表明,立管顶端倾斜角度改变对立管最大弯矩有显著影响,顶端倾角范围宜在80°~85°。在风浪流综合作用下,由于横摇与纵摇运动的耦合作用,横浪和尾斜浪向立管顶端最大弯矩显著增大,在作业过程中应引起关注。展开更多
The maximum bending moment or curvature in the neighborhood of the touch down point （TDP） and the maximum tension at the top are two key parameters to be controlled during deepwater J-lay installation in order to en...The maximum bending moment or curvature in the neighborhood of the touch down point （TDP） and the maximum tension at the top are two key parameters to be controlled during deepwater J-lay installation in order to ensure the safety of the pipe-laying operation and the normal operation of the pipelines. In this paper, the non-linear governing differential equation for getting the two parameters during J-lay installation is proposed and solved by use of singular perturbation technique, from which the asymptotic expression of stiffened catenary is obtained and the theoretical expression of its static geometric configuration as well as axial tension and bending moment is derived. Finite element results are applied to verify this method. Parametric investigation is conducted to analyze the influences of the seabed slope, unit weight, flexural stiffness, water depth, and the pipe-laying tower angle on the maximum tension and moment of pipeline by this method, and the results show how to control the installation process by changing individual parameters.展开更多
The pipe configuration and internal loads along the pipeline during the pipeline laying process have long been the focus of engineers. Most researchers simplify the seabed to be rigid and the water to be calm, ignorin...The pipe configuration and internal loads along the pipeline during the pipeline laying process have long been the focus of engineers. Most researchers simplify the seabed to be rigid and the water to be calm, ignoring the pipe embedment into the seabed and the influence of ocean currents. In this paper, a novel numerical approach is proposed for the laying of pipelines in the so-called J-lay method, taking into account the importance of both pipe embedment and ocean currents. The pipeline is divided into two parts, one part suspended in water, and the other laid on the seabed. The continuity of the two parts at the touch down point (TDP) is guaranteed to make a whole. The feasibility of the model is proved by the comparison between the present model and an analytical model, which shows good agreement in both pipeline configuration and bending moment distribution. Finally, parametric study was performed to consider the influence of current velocity, water depth, top inclination angle, and seabed stiffness, and conclusions are drawn.展开更多
文摘以3000 m J-Lay型深水铺管船作业为研究对象,建立全耦合数值分析模型。通过准静态分析研究立管敏感性参数变化规律,确定铺管作业时最优立管顶端倾角。考虑剖面流、风和波浪综合作用,对不同工况下铺管作业过程进行数值模拟,对铺管作业过程中立管受力特征、顶端固定点运动状态进行预报和研究。研究表明,立管顶端倾斜角度改变对立管最大弯矩有显著影响,顶端倾角范围宜在80°~85°。在风浪流综合作用下,由于横摇与纵摇运动的耦合作用,横浪和尾斜浪向立管顶端最大弯矩显著增大,在作业过程中应引起关注。
基金financially supported by the National Basic Research Program of China(Grant No.2011CB013702)the National Natural Science Foundation of China(Grant No.50979113).1
文摘The maximum bending moment or curvature in the neighborhood of the touch down point （TDP） and the maximum tension at the top are two key parameters to be controlled during deepwater J-lay installation in order to ensure the safety of the pipe-laying operation and the normal operation of the pipelines. In this paper, the non-linear governing differential equation for getting the two parameters during J-lay installation is proposed and solved by use of singular perturbation technique, from which the asymptotic expression of stiffened catenary is obtained and the theoretical expression of its static geometric configuration as well as axial tension and bending moment is derived. Finite element results are applied to verify this method. Parametric investigation is conducted to analyze the influences of the seabed slope, unit weight, flexural stiffness, water depth, and the pipe-laying tower angle on the maximum tension and moment of pipeline by this method, and the results show how to control the installation process by changing individual parameters.
基金Project (No. 50779061) supported by the National Natural Science Foundation of China
文摘The pipe configuration and internal loads along the pipeline during the pipeline laying process have long been the focus of engineers. Most researchers simplify the seabed to be rigid and the water to be calm, ignoring the pipe embedment into the seabed and the influence of ocean currents. In this paper, a novel numerical approach is proposed for the laying of pipelines in the so-called J-lay method, taking into account the importance of both pipe embedment and ocean currents. The pipeline is divided into two parts, one part suspended in water, and the other laid on the seabed. The continuity of the two parts at the touch down point (TDP) is guaranteed to make a whole. The feasibility of the model is proved by the comparison between the present model and an analytical model, which shows good agreement in both pipeline configuration and bending moment distribution. Finally, parametric study was performed to consider the influence of current velocity, water depth, top inclination angle, and seabed stiffness, and conclusions are drawn.
