柔性立管与防弯器耦合有限元建模研究

Research on finite element modeling of flexible riser and bend stiffener coupled

为研究防弯器与柔性立管的组合结构在拉力荷载下的曲率分布和变形特征问题,采用ABAQUS有限元软件建立了基于梁-实体单元结构耦合的实体-表面(SFM3D4单元)-梁有限元模型(实体-SFM-梁有限元模型)和实体-SFM-梁(Tie)有限元模型,并与理论模型进行对比验证。结果表明:实体-SFM-梁有限元模型不仅可以实现柔性立管较大轴向抗拉刚度和较小抗弯刚度的同步模拟,还能考虑防弯器与柔性立管变形后的相对滑动,进而准确地模拟拉力荷载作用下柔性立管与防弯器组合结构的曲率分布和变形特征;柔性立管抗拉刚度在一定范围内对柔性立管的曲率分布有较大的影响,而防弯器与柔性立管之间的摩擦系数对柔性立管的曲率分布基本没有影响。

To investigate the curvature distribution and deformation characteristics of the combined structure of bend stiffener and flexible riser under tension loading, the finite element software ABAQUS is adopted to develop the solidSFM-beam finite element model and solid-SFM-beam(Tie) finite element model based on beam-solid element structural coupling, and the simulation results are compared with the theoretical model. The results show that solid-SFM-beam finite element model can not only realize synchronous simulation of the large axial tensile stiffness and the small bending stiffness of the flexible riser, but also consider the relative sliding of the bend stiffener and the flexible riser after deformation, and thereby accurately simulate the curvature distribution and deformation characteristics for the combined structure of flexible riser and bend stiffener under tensile load;the tensile stiffness of flexible riser has large influence on the curvature distribution of flexible riser in a certain range, while the friction coefficient between bend stiffener and flexible riser has little effect on the curvature distribution of flexible riser.