顶部浮体激励下钢悬链线立管的动力响应分析

Dynamic Responses of Simple Catenary Riser Subject to Top End Excitation

考虑钢悬链线立管大变形的特性以及内流的影响,利用Kane方法和拉格朗日应变理论建立钢悬链线立管的二维动力学模型。将顶部浮体的激励简化为一个沿顺流向的周期作用力施加于立管顶部,采用平均加速度法求解立管的动力响应。探讨顶部浮体不同激励频率下立管的非线性动力响应以及内流流速的大小对管道共振响应幅值的影响。

The simple catenary riser is often used as a flexible link between undersea bore head and subsurface offshore platform. In order to carry out the performance-based design of the marine risers, the evaluation of their dynamic responses to top end excitations is imperative. In this study, the nonlinear equations of motion are derived based on Kane＇s method in combination with Lagrangian-strain definition, which capable of analyzing large-amplitude vibrations of a simple catenary riser with internal fluid. Investigation of the dynamic responses of marine riser to top end excitation in lateral directions is achieved using a Newmark Average Acceleration Method. It is found that resonant phenomenon can be observed from the responses, while the internal flow rate remarkably affects the displacement amplitudes of the marine riser＇ resonant responses.