Improvement of the bending behavior of a flexible riser : Part I – nonlinear bending behavior considering the shear deformation of polymer layers

Yun, Ran-Hui; Jang, Beom-Seon; Kim, Jung Du

doi:10.1016/j.apor.2020.102204

Cited by 8 publications

(7 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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%

“…Most of them have simplified the numerical model [ 82 , 83 ]. Yun et al [ 119 ] simplified the structure of the carcass layer and pressure armor layer and studied the bending characteristics of unbonded flexible risers by applying the axisymmetric load and then the bending moment ( Figure 18 ). They investigated the effect of different axisymmetric loads on the bending characteristics, and the results of the calculations showed obvious hysteresis.…”

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

confidence: 99%

See 1 more Smart Citation

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

View full text Add to dashboard Cite

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.

show abstract

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

confidence: 99%

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

View full text Add to dashboard Cite

show abstract

“…Current research mainly focuses on how to accurately describe the slip characteristics of the helical tendon, including the tensile armor layer bending hysteresis model established by considering different friction models and based on the theory of bending beams [14,15]. An analytical analysis model considers the deformation characteristics of the tensile armor layer under the action of riser torque and bending around the axis [9]; the bending hysteresis model was established by considering the effect of shear deformation of the cylindrical shell layer structure on the riser [16].…”

Section: Introductionmentioning

confidence: 99%

Axial Tensile Ultimate Strength of an Unbonded Flexible Riser Based on a Numerical Method

Li,

Jiang,

Xing

et al. 2024

Materials

View full text Add to dashboard Cite

Unbonded flexible risers consist of several helical and cylindrical layers, which can undergo large bending deformation and can be installed to different configurations to adapt to harsh marine environments, and is a key equipment in transporting oil and gas resources from Ultra Deep Waters (UDWs) to offshore platforms. The helical interlayer of an unbonded flexible riser makes the structural behavior difficult to predict. In this paper, the axial tensile behavior and the axial tensile ultimate strength of an unbonded flexible riser are studied based on a typical 2.5-inch eight-layer unbonded flexible riser model, and verified through a theoretical method considering the contact between adjacent layers. First, the balance equation of separate layers is deduced by a functional principle, and then the overall theoretical model of an unbonded flexible riser is established considering the geometric relationship between adjacent layers. Then, the numerical model considering the detailed geometric properties of an unbonded flexible riser is established to simulate the axial tensile behavior. Finally, after being verified through the experimental results, the axial tensile stiffness and axial tensile strength of an unboned flexible riser considering the elasticity of the tensile armor layer are studied using the proposed two methods. Additionally, the effect of frictional coefficients is conducted. The numerical and theoretical results show good agreement with the test results, and the friction between adjacent layers would increase the axial tensile stiffness of an unbonded flexible riser.

show abstract

“…Based on the results and similarity theory, a similarity in ultimate strength between container ships and similar-scale models was proposed. Yun et al (2020) [11] conducted a study to improve the existing analytical model used to forecast the nonlinear bending behavior of flexible risers. In contrast to previous analytical models, in the present study, a series of equilibrium equations were derived considering the radial and shear deformations of multiple layers.…”

Section: Introductionmentioning

confidence: 99%

“…In shipyards, NASTRAN software has been primarily used for global ship analysis (MSC, 2018) [25]. Although Det Norske Veritas (DNV) classification increases due to the demands of ship owners, requests for structural research in shipyards, and classification approval, global ship analysis must be conducted using the DNV's Sesam tool instead of NASTRAN in certain cases.…”

Section: Introductionmentioning

confidence: 99%

Shear Force and Bending Moment Tuning Algorithm of Shuttle Tanker Model for Global Structural Analysis

Lim,

Han,

Kang

et al. 2023

JMSE

View full text Add to dashboard Cite

Global ship analysis is conducted using a finite element model (FE model) for ship design and construction, which involves structural, motion, and vibration analyses. It is crucial to examine the structural safety of the hull and motion response. In the ship FE model used in global ship analysis, weight distribution is employed to adjust the light weight and center of gravity (COG), which are required to perform the analysis. Further, the FE model needs to satisfy the required longitudinal shear force (SF) and bending moment (BM) under the loading conditions of the ship. Moreover, the SF and BM in the ship Trim and Stability data are utilized to perform shear force tuning (SFT) and bending moment tuning (BMT) for the ship FE model. This ensures the ship model exhibits curves of the SF and BM that coincide with those of the ship. The SFT and BMT for the ship FE model are time-consuming and costly. Thus, to address these limitations, we propose an effective and accurate algorithm and program for SFT and BMT. Accordingly, we developed a C#-based algorithm to tune the weight, SF, BM, and COG of the ship FE model to the required target value. Finally, the accuracy of the newly developed algorithm was analyzed and compared by applying it to the shuttle tanker FE model under the ballast and full load conditions. Accuracy was within tolerance in both loading conditions. The average errors of SF and BM were smaller in the ballast condition than in the full load condition, and the errors were smaller at the bow than at the stern.

show abstract

Improvement of the bending behavior of a flexible riser : Part I – nonlinear bending behavior considering the shear deformation of polymer layers

Cited by 8 publications

References 16 publications

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

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

Axial Tensile Ultimate Strength of an Unbonded Flexible Riser Based on a Numerical Method

Shear Force and Bending Moment Tuning Algorithm of Shuttle Tanker Model for Global Structural Analysis

Contact Info

Product

Resources

About