Abstract To address the weight and corrosion challenge in deep-water, replacing the steel tensile armour in flexible pipes with composite materials is an alternative conceptual approach. An axisymmetric structural responses model is built for this novel composite armoured flexible pipe, with interlayer gaps that may occur in the unbonded structure considered through an iterative algorithm. The tensile strength of steel and composite armoured pipes are predicted based on different constitutive relations of steel and composite. Essential quantities are obtained, such as tensile stiffness, deformations of each layer and interlayer gaps or contact pressures. Considering the helix form of carcass and pressure armour, a finite element model is established for the verification of the theoretical model. Case study shows that the tensile stiffness of flexible pipe is overestimated with the interlayer gap ignored. Compared with steel armoured flexible pipe, the composite armoured pipe, whose tensile stiffness decreases less as external pressure increases, meanwhile has higher values of tensile ultimate strength and torsion stiffness. Some suggestions about fiber types and volume fraction for composite tensile strips are given to ensure good performance of axial tensile strength and stiffness.

中文翻译：

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复合拉伸铠装软管的轴对称结构行为

摘要 为了解决深水中的重量和腐蚀挑战，用复合材料代替柔性管道中的钢拉伸铠装是一种替代的概念方法。为这种新型复合铠装柔性管建立了轴对称结构响应模型，通过迭代算法考虑了可能在未粘合结构中出现的层间间隙。根据钢和复合材料的不同本构关系预测钢和复合材料铠装管的抗拉强度。获得基本量，例如拉伸刚度、每层的变形和层间间隙或接触压力。考虑到胎体和压力甲的螺旋形式，建立有限元模型对理论模型进行验证。案例研究表明，在忽略层间间隙的情况下，柔性管的拉伸刚度被高估。复合铠装管与钢铠软管相比，其抗拉刚度随外压增大而降低的幅度较小，同时具有较高的抗拉极限强度和扭转刚度值。对复合材料拉伸带的纤维类型和体积分数提出了一些建议，以确保其具有良好的轴向拉伸强度和刚度。