Abstract Steel lazy wave risers (SLWRs) are regarded as an alternative option of advanced steel catenary risers (SCRs), and their nonlinear dynamic performance is a great challenge as subjected to vessel offsets and wave-current loads. Especially, the mechanical features would be more complicated due to the introduction of the buoyancy module system. This paper presents a numerical model based on three-dimensional (3D) large deformation rod theory. The whole space model is divided into four parts: touchdown segment, decline segment, buoyancy segment and hang-off segment to accurately simulate the favorable motion performance of the SLWR. The governing equations are established in terms of a global coordinate system, which involves the effects of vessel motion, wave-current loads, riser-seabed interaction and internal flow. The finite element method combined with an Adams-Moulton scheme is applied to discretize the governing equation and update the time integration. The numerical model is verified with the published results and numerical simulations are executed to determine the dynamic behavior of the SLWR. The comprehensive parametric analysis is then conducted to investigate the influences of motion amplitude, motion period, length of buoyancy segment, wave-current load, internal flow, seabed friction on the SLWR's dynamic behavior.

中文翻译：

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内流与海底相互作用的深水钢制懒波立管的非线性有限元动力学分析

摘要 钢质惰性波浪立管（SLWRs）被认为是先进钢悬链线立管（SCRs）的替代选择，其非线性动态性能在承受船舶偏移和波流载荷时是一个巨大的挑战。特别是由于引入了浮力模块系统，机械特性会更加复杂。本文提出了一种基于三维 (3D) 大变形杆理论的数值模型。整个空间模型分为着陆段、下降段、浮力段和悬空段四个部分，以准确模拟SLWR的良好运动性能。控制方程是根据全局坐标系建立的，其中涉及船舶运动、波流载荷、立管-海底相互作用和内部流动的影响。有限元方法与 Adams-Moulton 方案相结合，用于离散控制方程并更新时间积分。数值模型通过公布的结果进行验证，并执行数值模拟以确定 SLWR 的动态行为。然后进行综合参数分析，研究了运动幅度、运动周期、浮力段长度、波流载荷、内部流动、海底摩擦对SLWR动力行为的影响。