Validity and limitation of analytical models for the bending stress of a helical wire in unbonded flexible pipes

Tang, Minggang; Yang, C F; Yan, Jun; Yue, Qianjin

doi:10.1016/j.apor.2014.12.004

Cited by 31 publications

(7 citation statements)

References 27 publications

(41 reference statements)

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“…Zhang and Qiu (2007) proposed a simple model to simulate the behavior of tensile armored steel wire during unbonded flexible pipe bending and analyzed the displacement field of the wire, stress-strain in the wire cross-section, armored wire extrusion with other layers, and bending hysteresis. Tang et al (2015) created a finite element model to investigate the bending behavior of unbonded flexible pipes. Lu et al (2017) and Lu et al (2020) developed a full three-dimensional finite element model that takes into account interlayer friction and contact effects, validated it by the theoretical model, and studied the effect of the friction coefficient on the bending stress, contact pressure, and friction force of the armored steel wire using the finite element model.…”

Section: Theoretical and Simulation Research Progress On Armor Layer ...mentioning

confidence: 99%

An Overview of Structural Design, Analysis and Common Monitoring Technologies for Floating Platform and Flexible Cable and Riser

Zhao

Gou

et al. 2022

China Ocean Eng

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Offshore oil and gas development plays an important part in the global energy sector. Offshore platforms and flexible pipes are the key equipments in the whole offshore oil and gas development system. Because of the randomness and uncertainty of wave and current loads in the ocean environment, the structural design and mechanical analysis of the marine equipment can be highly complicated. Therefore, this paper reviews the recent works of the theoretical model, numerical simulation, and experimental test in three research areas: hydrodynamic analysis of offshore platforms, structural mechanics analysis of flexible pipe and cable, and monitoring technology of offshore floating structures under marine loads. By analyzing their main research methods and key technical difficulties, this paper provides theoretical basis and technical support for the reliability engineering application of offshore platforms and flexible pipelines. Also, China is relatively backward in the design of marine floating platform, the design, analysis and testing of flexible pipeline and cable, as well as the marine equipment prototype monitoring technology research. Calling for breakthroughs at the earliest possible stage in the above fields, prime research should be focused on and strategic planning should be made to deal with “key areas and stranglehold problems”. It is of great significance for the development of China’s deep-sea energy and resource development of independent technology and on time to achieve the “carbon peak” national strategic objectives.

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Section: Theoretical and Simulation Research Progress On Armor Layer ...mentioning

confidence: 99%

An Overview of Structural Design, Analysis and Common Monitoring Technologies for Floating Platform and Flexible Cable and Riser

Zhao

Gou

et al. 2022

China Ocean Eng

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“…[15], where the numerically and experimentally obtained stress of helical wires showed good agreement. However, Tang et al [24] indicated that Eq. (13) may overestimate the effect of the local flexure on the bending stress at critical point.…”

Section: Riser-seabed Interaction Modelmentioning

confidence: 99%

“…(13) may overestimate the effect of the local flexure on the bending stress at critical point. The reason may be that Tang et al [24] applied large curvature, 1 m À1 , to the flexible riser, which may mitigate the local flexure due to the significantly lateral sliding. This study assumed that the two equations can reasonably consider the effect of the helical wire local flexure on the stress at critical point in global response of flexible riser.…”

Section: Riser-seabed Interaction Modelmentioning

confidence: 99%

Fatigue Damage Study of Helical Wires in Catenary Unbonded Flexible Riser Near Touchdown Point

Wang

Xue

et al. 2017

Journal of Offshore Mechanics and Arctic Engineering

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This study presents an analytical model of flexible riser and implements it into finite-element software abaqus to investigate the fatigue damage of helical wires near touchdown point (TDP). In the analytical model, the interlayer contact pressure is simulated by setting up springs between adjacent interlayers. The spring stiffness is iteratively updated based on the interlayer penetration and separation conditions in the axisymmetric analysis. During the bending behavior, the axial stress of helical wire along the circumferential direction is traced to determine whether the axial force overcomes the interlayer friction force and thus lead to sliding. Based on the experimental data in the literature, the model is verified. The present study implements this model into abaqus to carry out the global analysis of the catenary flexible riser. In the global analysis, the riser–seabed interaction is simulated by using a hysteretic seabed model in the literature. The effect of the seabed stiffness and interlayer friction on the fatigue damage of helical wire near touchdown point is parametrically studied, and the results indicate that these two aspects significantly affect the helical wire fatigue damage, and the sliding of helical wires should be taken into account in the global analysis for accurate prediction of fatigue damage. Meanwhile, different from the steel catenary riser, high seabed stiffness may not correspond to high fatigue damage of helical wires.

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“…This has increased the difficulty of analyzing this helically wound structure through FEM in an accurate way, and thus make infeasible the optimization design of this type of structure. There are many hypotheses in such theoretical analysis, and the numerical model cannot simulate the helically wound structure with large length (Tang et al , 2015).…”

Section: Introductionmentioning

confidence: 99%

Multi-scale analysis for helically wound structures with one-dimensional periodicity

Yan

Yang

et al. 2019

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Purpose The purpose of this study is to present a multi-scale analysis methodology for calculating the effective stiffnesses and the micro stresses of helically wound structures efficiently and accurately. The helically wound structure is widely applied in ocean and civil engineering as load-bearing structures with high flexibility, such as wire ropes, umbilical cables and flexible risers. Their structures are usually composed of a number of twisted subcomponents with relatively large slender ratio and have the one-dimensional periodic characteristic in the axial direction. As the huge difference between the axial length and the cross-section size of this type of structures, the finite element modeling and theoretical analysis based on some assumption are usually unavailable leading to the reduction of computability; even the optimization design becomes infeasible. Design/methodology/approach Based on the asymptotic homogenization theory, the one-dimensional periodic helically wound structure is equivalent to the one-dimensional homogeneous beam. A novel implementation of the homogenization is derived for the analysis of the effective mechanical properties of the helically wound structure, and the tensile, bending, torsional and coupling stiffness properties of the effective beam model are obtained. On this basis, a downscaling analysis formation for the micro-component stress in the one-dimensional periodic wound structure is constructed. The stress of micro-components in the specified geometry position of the helically wound structure is obtained basing on the asymptotic homogenization theory simultaneously. Findings By comparing with the result from finite element established accurately, the established multi-scale calculation method of the one-dimensional periodic helically wound structure is verified. The influence of size effects on the macro effective performance and the micro-component stress is discussed. Originality/value This paper will provide the theoretical basis for the efficient elastoplastic analysis of the helically wound structure, even the fatigue analysis. In addition, it is necessary to point out that the axial length of the helically wound structure in the general engineering problems that such as deep-sea risers and submarine cables.

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Validity and limitation of analytical models for the bending stress of a helical wire in unbonded flexible pipes

Cited by 31 publications

References 27 publications

An Overview of Structural Design, Analysis and Common Monitoring Technologies for Floating Platform and Flexible Cable and Riser

An Overview of Structural Design, Analysis and Common Monitoring Technologies for Floating Platform and Flexible Cable and Riser

Fatigue Damage Study of Helical Wires in Catenary Unbonded Flexible Riser Near Touchdown Point

Multi-scale analysis for helically wound structures with one-dimensional periodicity

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