Predicting, Measuring and Implementing Friction and Bending Stresses in Dynamic Umbilical Design

Ekeberg, Knut I.; Ottesen, Torfinn; Aarstein, J.; Sævik, Svein; Ye, N.; Igland, Ragnar T.

doi:10.4043/17986-ms

Cited by 6 publications

(5 citation statements)

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“…The differences between the two results are attributed to the fact that the radius reduction of helical tendon is neglected in the analytical model, which is induced by the contractions of central assembly and insertions of the helical tendon with the sheaths. The similar trends and differences have also been reported by reference (Ekeberg et al (2006)). To consider the effect of the radius reduction of helical tendon, a modify axial stiffness formula has been introduced as…”

Section: Stepsupporting

confidence: 90%

“…From their results, axially symmetric relationships between the axial loads and the strains have been found; and the prediction achieved good agreements with experimental results. However, when it comes to the Corresponding author, Professor, E-mail: shixiao.fu@sjtu.edu.cn tensional stiffness of the un-bonded umbilical, the effects of the radius reduction caused the predicted result 2-4 times larger than the experimental result (Ekeberg et al 2006). As for the bending properties of the multi layer structures, more difficulties is confronted with due to the large nonlinearity behaviors caused by the sliding of the helical components.…”

Section: Introductionmentioning

confidence: 99%

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Stress analysis model for un-bonded umbilical cables

Chen¹,

Song³

et al. 2013

Ocean Systems Engineering

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For the optimization design and strength evaluation of the umbilical cable, the calculation of cross section stress is of great importance and very time consuming. To calculate the cross section stress under combined tension and bending loads, a new integrated analytical model of umbilical cable is presented in this paper. Based on the Hook's law, the axial strain of helical components serves as the tensile stress. Considering the effects of friction between helical components, the bending stress is divided into elastic bending stress and friction stress. For the former, the elastic bending stress, the curvature of helical components is deduced; and for the latter, the shear stress before and after the slipping of helical components is determined. This new analytical model is validated by the experimental results of an umbilical cable. Further, this model is applied to estimate the extreme strength and fatigue life of the umbilical cable used in South China Sea.

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Section: Stepsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Stress analysis model for un-bonded umbilical cables

Chen¹,

Song³

et al. 2013

Ocean Systems Engineering

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“…More importantly, static and dynamic friction coefficients and the corresponding smooth transition between these two friction coefficients were observed by Rabinowicz [8] in some tests. Several works have been reported in the literature, see [3,9,10,11,12,13], concerning the hysteric bending behavior of helix elements versus full scale tests. Most of the work demonstrated that good correlation in terms of axial stress of helix elements and hysteresis bending moment-curvature relationship.…”

Section: Introductionmentioning

confidence: 99%

Friction models for evaluating dynamic stresses in non-bonded flexible risers

Dai

Sævik

2017

Marine Structures

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This paper addresses friction models used for evaluating dynamic stresses in non-bonded flexible risers. A review of the most commonly used methods to model friction between layers in such structures was performed. Four models for calculating friction under dynamic contact pressure and constant shear interaction stick stiffness conditions were then formulated to enable stress calculation of cross-sections exposed to variable tension and bending loads. The friction models were implemented into a computer code used for numerical studies. A sensitivity study was carried out to determine the optimum shear interaction stick stiffness parameter, K 0 , with respect to representing the plane surfaces remain plane assumption. This was followed by an investigation of the performance of the developed models with respect to the tendon axial force next to the outermost fibre position. The proposed friction models were also verified against full scale tests in terms of bending moment-curvature data. As the test data indicated less bending stiffness in the stick domain than that can be obtained by the plane surfaces remain plane assumption, a method to estimate the parameter K 0 was proposed, which accounted for the shear deformation of the plastic layers. The initial strain concept was further applied to deal with the significant hysteresis observed in the test data for low internal pressures pointing the way forward with respect to dealing with this effect in stress analysis. Furthermore, a friction model comparison study was carried out for investigating the static friction effect on the axial force at the outermost fibre position and the bending moment-curvature relationship.

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“…Predicting, Measuring and Implementing Friction Stresses in dynmaic analysis is performed in this study bu Abaqus's sub-modelng and conact definition. However, this issue was dealt using a different approach in [6].…”

Section: Remarksmentioning

confidence: 99%

Integrity of Subsea Control Umbilical

Yasseri

Yasseri²,

Wang

2014

Volume 6A: Pipeline and Riser Technology

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Controlling subsea oil and gas production systems fibre optics, power cables and tubes for the chemical for injection and fluid for hydraulic are arranged in helical bundles in successive layers. Shaped thermoplastic fillers are used to separate components and out voids in the cross section. If necessary, armour provide strength for the dynamic loads. This paper describes the application of 3D finite element method to assess the structural Integrity of subsea umbilicals, including the interaction between the constituent elements. uses a global analysis to determine the internal force analyses (sub-modelling) for detailed stress evaluation. is used for this purpose, due to its capability problems under severe discontinuities due contact conditions. This paper also discusses the umbilicals interaction w seabed. The focus of this paper is on the fatigue life calculation.

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Predicting, Measuring and Implementing Friction and Bending Stresses in Dynamic Umbilical Design

Cited by 6 publications

References 0 publications

Stress analysis model for un-bonded umbilical cables

Stress analysis model for un-bonded umbilical cables

Friction models for evaluating dynamic stresses in non-bonded flexible risers

Integrity of Subsea Control Umbilical

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