Monitoring the slip of helical wires in a flexible riser under combined tension and bending

Tang, Minggang; Li, Shengpeng; Zhang, Hao; Bian, Xin; Zhao, Xiaoyu

doi:10.1016/j.oceaneng.2022.111512

Cited by 8 publications

(4 citation statements)

References 18 publications

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“…It should be noted that the interlayered contact and friction cause the stress of helical wires obvious nonlinear, so their accurate prediction is of great significance for the calculation of fatigue life. However, for the current analyzing theory of fatigue stress, there is a lack of accurate description of the wire behavior in the stick-slip stage [21], which has a decisive effect on the fatigue life when the riser is subjected to large axisymmetric loads and small bending curvature. In addition, after the wire enters the full-slip stage, it is worth further exploring whether the bending stress of the wire under axial tension can be simulated through the spring theory [22].…”

Section: Analysis and Discussion Of Structural Responsesmentioning

confidence: 99%

Flexible Pipes

Tang¹

2023

Pipeline Engineering - Design, Failure, and Management

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An unbonded flexible pipe is one of the most important equipment in offshore engineering, transporting oil and gas between the floater on the sea and the well located on the seabed. Flexible pipes consist of several metallic helical-reinforced layers and internal and external polymer sheaths, and relative slip between the layers is allowed, so that the structure show high axial stiffness and radial stiffness associated with relatively low bending stiffness. During the operation and installation, the flexible pipe will be subjected to complex and coupled loads such as tension, internal pressure, external pressure, torsion and bending, which lead to multiple structural failures. This chapter will present the current theoretical models and research progress to effectively evaluate the response of such composite structure, providing reference ideas for the engineering design of the flexible pipes.

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Section: Analysis and Discussion Of Structural Responsesmentioning

confidence: 99%

Flexible Pipes

Tang¹

2023

Pipeline Engineering - Design, Failure, and Management

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“…Bending hysteresis characteristics remain a hot topic for unbonded flexible risers [ 111 , 112 , 113 , 114 , 115 , 116 ]. For the tensile armor layer structure, current research mainly focuses on how to accurately describe the slip characteristics of the helical tendon using the following models: the tensile armor layer bending hysteresis model established by considering different friction models and based on the theory of bending beams [ 117 , 118 ]; the analytical analysis model considering the deformation characteristics of the tensile armor layer under the action of riser torque and bending around the axis [ 62 ]; the bending hysteresis model established by considering the effect of shear deformation of the cylindrical shell layer structure in the riser [ 119 ].…”

Section: Development Of Cross-sectional Properties Of An Unbonded Fle...mentioning

confidence: 99%

Review of the Development of an Unbonded Flexible Riser: New Material, Types of Layers, and Cross-Sectional Mechanical Properties

Liu,

Qu,

Chen

et al. 2024

Materials

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Unbonded flexible risers consist of several helical and cylindrical layers, which can undergo large bending deformation and can be installed in different configurations to adapt to harsh marine environments; thus, they can be applied to transport oil and gas resources from ultra-deep waters (UDW). Due to their special geometric characteristics, they can ensure sufficient axial tensile stiffness while having small bending stiffness, which can undergo large deflection bending deformation. In recent years, the development of unbonded flexible risers has been moving in an intelligent, integrated direction. This paper presents a review of unbonded flexible risers. Firstly, the form and properties of each interlayer of an unbonded flexible riser are introduced, as well as the corresponding performance and configuration characteristics. In recent years, the development of unbonded flexible risers has been evolving, and the development of machine learning on unbonded flexible risers is discussed. Finally, with emphasis on exploring the design characteristics and working principles, three new types of unbonded flexible risers, an integrated production bundle, an unbonded flexible riser with an anti-H2S layer, and an unbonded flexible riser with a composite armor layer, are presented. The research results show that: (1) the analytical methods of cross-sectional properties of unbonded flexible risers are solved based on ideal assumptions, and the computational accuracy needs to be improved. (2) Numerical methods have evolved from equivalent simplified models to models that account for detailed geometric properties. (3) Compared with ordinary steel risers, the unbonded flexible riser is more suitable for deep-sea resource development, and the structure of each layer can be designed according to the requirements of the actual environment.

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“…Their role is to transport the hydrocarbons, fluids, and gas between the production facilities and the subsea installations. They are composed of several metallic and polymeric layers and their structure is illustrated in other studies [1,2]. Carbon steels have a strong position in flexible pipe production due to their excellent mechanical properties, availability, and cost [3].…”

Section: Introductionmentioning

confidence: 99%

“…Carbon steels have a strong position in flexible pipe production due to their excellent mechanical properties, availability, and cost [3]. The carbon steels that are used in flexible pipes are subjected to tension and compression and are prone to failure [2]. Therefore, the potential hydrogen embrittlement of flexible pipe carbon steels is a key factor that should be considered in material selection.…”

Section: Introductionmentioning

confidence: 99%