中文摘要：

基于大挠度柔性索理论,分别采用大挠度曲线梁、弹性地基梁模拟钢悬链线立管的悬垂段和流线段,揭示触地点在不同海床刚度和浮体运动条件下的动力响应。其中,SCR控制方程的建立和求解采用非线性有限元法,数值积分采用Newmark-β法,海床约束采用弹簧-阻尼系统模拟。结合SCR顶端的运动边界条件,求解线性波浪载荷条件下SCR触地点的动力响应及应力状态。通过工程算例,分析海床刚度对SCR触地点挠度及应力大小的影响。研究表明：海底土刚度越大,SCR的极限应力越大,疲劳损伤越严重;SCR的竖向运动,将会引起触地点处的峰值弯曲应力。

英文摘要：

The dynamic response at touchdown points（TDP） is presented under different soil stiffness and the motion of a floating structure.The sag bend and the flowline of the steel catenary riser（SCR） have been simulated with a slender beam and an elastic foundation beam model based on the assumption of a large deformation in bending and small extension.In this approach,the SCR＇s governing equation is established and solved using nonlinear FEM,Newmark-β method is employed for time-domain integration.The sea bottom is modeled by a spring-damping system in the dynamic simulation.The dynamic response and stress at the TDP under linear wave loads are given considering boundary conditions at the top of SCR.Theoretical results are compared with numerical solutions.It is shown that the level of soil stiffness used in SCR analysis is too high then the predicted fatigue life,that the extreme bending stress at the TDP is induced by the vertical motion of SCR.