Abstract The present paper addresses the circular armour wire lateral buckling in umbilicals. An asymmetric non-linear finite element model is developed to analyze a single armour wire subjected to combined constant axial compression and uniform cyclic curvatures. A parametric case study is performed for an armour wire from a nine-hose umbilical cable, where the armour wire pitch number, applied axial compressive load and minimum and maximum curvatures in the applied cyclic bending are varied. The armour wire end shortenings, transverse sliding in cyclic bending, the buckling shapes and equilibrium paths after numerous bending cycles, the critical buckling loads, the stress states at the onset of lateral buckling, and the required number of bending cycles that triggers lateral buckling are obtained and extensively discussed. The critical buckling loads given by the FE model have been compared with an existing analytical formulation, indicating that the analytical model is reliable for small cyclic curvatures. Moreover, an empirical model is proposed for the required number of bending cycles to trigger the lateral buckling and good correlation with the FE results has been observed.

中文翻译：

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脐带环形铠装线横向屈曲的有限元研究

摘要 本文讨论了脐带中圆形铠装线的横向屈曲。开发了一个非对称非线性有限元模型来分析承受组合恒定轴向压缩和均匀循环曲率的单个铠装线。对来自 9 软管脐带电缆的铠装线进行了参数化案例研究，其中铠装线节距数、施加的轴向压缩载荷以及施加的循环弯曲中的最小和最大曲率是不同的。铠装线端部缩短、循环弯曲中的横向滑动、多次弯曲循环后的屈曲形状和平衡路径、临界屈曲载荷、横向屈曲开始时的应力状态以及触发横向屈曲所需的弯曲循环次数为获得并广泛讨论。有限元模型给出的临界屈曲载荷与现有的分析公式进行了比较，表明分析模型对于小循环曲率是可靠的。此外，还针对触发横向屈曲所需的弯曲循环次数提出了一个经验模型，并观察到与有限元结果的良好相关性。