A theoretical approach to prediction of service life of unbonded flexible pipes under dynamic loading conditions

Claydon, P.; Cook, G.; Brown, Peter A.; Chandwani, Ramesh

doi:10.1016/0951-8339(92)90011-d

Cited by 30 publications

(11 citation statements)

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“…Theoretical prediction of the slip between the helical tendons and the cylindrical layers has been a subject of investigation for many scholars [5,[8][9][10]. Tendons were assumed to slide in both their axial and their transverse directions and to follow geodesic paths after the slip.…”

Section: Introductionmentioning

confidence: 99%

Slip initiation and progression in helical armouring layers of unbonded flexible pipes and its effect on pipe bending behaviour

Kraincanic

Kebadze

2001

The Journal of Strain Analysis for Engineering Design

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Comparatively straightforward analytical formulations are given for determining the bending moment-curvature relationship for a helical layer in unbonded flexible pipes. The approach takes into account the non-linearity of the layer caused by sliding of individual helical elements between the surrounding layers. Bending stiffness of a helical layer is found to be a function of bending curvature, interlayer friction coefficients and interlayer contact pressures. The analysis presented here is based on the Coulomb friction model and is derived using the principle of virtual work. Theoretical results for a typical unbonded flexible pipe using the non-linear formulation for helical layers are compared with experimental data.

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Section: Introductionmentioning

confidence: 99%

Slip initiation and progression in helical armouring layers of unbonded flexible pipes and its effect on pipe bending behaviour

Kraincanic

Kebadze

2001

The Journal of Strain Analysis for Engineering Design

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“…Um tubo flexível ou cabo umbilical falhará, se um de seus componentes falhar. Tal fato pode ser conseqüência de (ver, por exemplo, Jiao, 1992;Claydon et al, 1992): Há ainda o carregamento associado ao fluxo interno de óleo/gás (Patel & Seyed,1989), que pode se tornar relevante para tubos flexíveis, ou mesmo tubos de aço.…”

Section: Figura 2-3 Tubo Flexível Típicounclassified

Mecânica de cabos e tubos submersos lançados em catenária: uma abordagem analítica e experimental.

Pesce¹

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Submerged cables and pipes, in 'catenary' configuration, are essential systems in offshore oil industry, particularly in deep-water exploration. The structural-mechanics behavior of this kind of system, in response to gravitational, hydrostatic, environmental loads and to motions imposed by the floating unit from which it is suspended, is inherentely non-linear. Geometric non-linearities, as those represented by the one-side constraint at the touchdown point, as well as hydrodynamic ones, are just few examples of such non-linear characteristics.This work treats the static configuration as well as the dynamic response problems.Emphasis is given to the study of curvature distribution in the extremities neighborhoods, either close to the touchdown point or to the suspension point, as those regions are critical, concerning design. The approach is analytical and experimental.The static problem is formulated and discussed under the classical theory of thin rods.The two-dimensional problem is analysed in depth. The effect of flexural rigidity is shown to be confined to small regions, close to the extremities, since no other intermediate restraint is supposed to exist, and classified as a standard singular perturbation problem in applied mathematics. The curvature in the touch-down point region is treated under the boundary-layer technique approach. An analytical solution is then constructed. The soil flexibility effect is properly incorporated and discussed.The analytical solution is compared to results of specifically conducted experiments, and validated. The boundary-layer technique is then applied to the curvature distribution in the upper end region, in the presence of a flexible end-fitting, and an analytical local solution is derived as well. A number of non-dimensional diagrams are presented and discussed under a designer perspective.

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“…Current methodologies concerning flexible pipe are generally divided into two categories i.e., analytical formulations and finite element models. The analytical models share many of the following simplifying assumptions, which significantly limit the range of applicability of the results: displacements and strains are small [2][3][4] ; some coupling terms in total stiffness matrix are neglected 4 ; the conventional elastic thinwalled theory can be assumed valid 3,5 ; tendons are restricted from rotating about their local helical axis; strains and/or stresses across the layer thickness are constant; thicknesses of layers remain constant during deformation 3 ; plane sections remain plane 4 ; ovalisation effects are neglected 4,6 ; contact and/or frictional effects are ignored [7][8][9][10][11] ; no slip occurs between layers 12 Flexible pipes, as a typical composite structure, are generally applied to the ocean oil engineering. The Carcass layer of flexible pipes, with its particular structural formation, demonstrates orthotropic properties and the moduli of the Carcass layer are not the material moduli.…”

Section: Introductionmentioning

confidence: 99%

“…This analytical method of equivalent moduli shows good capacity in the prediction of the behaviour of the flexible pipes, which provides practical and technical support for the application of unbonded flexible pipes. tendons are constrained to slide only along their own axis; tendons respond only axially, (bending and torsional stiffness neglected); the interlayer contact pressure is constant; the contribution of the plastic sheaths to the strength and stiffness of the pipe can be neglected; layers remain constantly in contact (no bird-caging effect) ; the radial deformation is the same for all layers 3,6,13 ; initial manufacturing residual stresses can be ignored 10 . Therefore all available analytical methods are restricted because of the complexity of modeling layers.…”

Section: Introductionmentioning

confidence: 99%

Equivalent Moduli of Carcass Layer in Flexible Pipes

Wang¹,

Liu²,

Chen³

2014

Asian J. Chem.

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A theoretical approach to prediction of service life of unbonded flexible pipes under dynamic loading conditions

Cited by 30 publications

References 1 publication

Slip initiation and progression in helical armouring layers of unbonded flexible pipes and its effect on pipe bending behaviour

Slip initiation and progression in helical armouring layers of unbonded flexible pipes and its effect on pipe bending behaviour

Mecânica de cabos e tubos submersos lançados em catenária: uma abordagem analítica e experimental.

Equivalent Moduli of Carcass Layer in Flexible Pipes

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