钢悬链线输流立管顶部浮体激励非线性响应研究

钢悬链线立管在上部附体激励作用下的动力响应在立管的性能化设计中是非常重要的。本文作者考虑钢悬链线立管轴向大应变的特性以及弯曲刚度和内流的影响，利用Hamilton原理和拉格朗日应变理论建立了立管的二维动力学模型。将外部流体的非线性作用力用Morison方程表示，通过Hermite插值函数对动力学方程进行离散，采用平均加速度法求解立管的动力响应。探讨了弯曲刚度的存在、内流流动和外部流体的非线性作用力对立管受浮体激励顺流向动力响应的影响。

Nolinear dynamic responses of fluid-conveying steelcatenary risers subjected to top excitation

In order to carry out the performance-based design of the deepwater steel catenary risers, the evaluation of their dynamic responses to top excitation is imperative. In this study, the energy function of the risers conveying fluid is derived from variational principle. Nonlinear equations of motion influenced by the nonlinear Morison waveform are obtained through Hamilton’s principle in combination with Lagrangian-strain definition. Investigation of the in-line dynamic responses of steel catenary risers is achieved using the finite element method and Newmark Average Acceleration Method. It is found that the bending stiffness and internal fluid velocity plays a major role in the responses, while the flow rate and drag force coefficients remarkably affects the displacement amplitudes of the marine risers’ resonant responses. Outflow velocity produce a significant effect on the bending moment and stress of the riser’s bottom end.