Time domain approach for coupled cross-flow and in-line VIV induced fatigue damage of steel catenary riser at touchdown zone

Wang, Kunpeng; Tang, Wenyong; Xue, Hong

doi:10.1016/j.marstruc.2015.02.004

Cited by 21 publications

(6 citation statements)

References 16 publications

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“…But when it comes to catenary risers, umbilicals and marine cables that have large curvature, are inclined at various angles to the flow, and experience significant changes in tension over their length, understanding of vortex-induced vibrations is much less well advanced. Related basic problems that have been studied experimentally or numerically include vortex shedding from yawed cylinders (King, 1977;Ramberg, 1983), vibrations of spring-mounted rigid cylinders, or of flexible cylinders, in yawed or sheared flow (Jain and Modarres-Sadeghi, 2013), the wake dynamics and vibrations of rigid cylinders whose axis is curved (strictly 'pipes': Miliou et al, 2007), and interactions at the touch-down point on a hard or a soft sea floor (Kim et al (2006), Wang et al (2015b)). Dynamics of catenary risers driven by vessel motions in initially still water have been studied by Chatjigeorgiou et al (2008), Pereira et al (2013) and Wang et al (2015a).…”

Section: Introductionmentioning

confidence: 99%

Laboratory measurements of the vortex-induced vibrations of an untensioned catenary riser with high curvature

Chaplin

King

2018

Journal of Fluids and Structures

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Measurements of the vortex-induced vibrations of an instrumented catenary model riser with high curvature and very low bending stiffness are presented and discussed. The riser had a diameter of 56mm and a length of 5.36m. It was tensioned only by its own weight and by drag and was tested in a recirculating water channel 2m deep at flow speeds up to 1.4m/s in both directions, i.e. with the upstream anchorage on the floor of the tank and the downstream one at the surface (defined as positive current cases), and then vice versa (negative currents). In many cases much of the riser rested on the tank floor with the touchdown point determined by the flow-induced forces on it. Attention is focused mainly on the frequencies of cross-flow vibrations after careful analysis of the effects of gravitational contamination on acceleration measurements. Response spectra were found to have a higher bandwidth than those of tensioned risers perpendicular to the flow and often exhibited more than one distinct peak. Dimensionless peak frequencies (having been normalised with respect to the diameter and a characteristic velocity) were much lower than that associated with a Strouhal number in the region of 0.2. In positive currents (based on the normal incident velocity at the top of the riser, where it was near vertical) it was generally uniform over the length of the riser at about 0.11. In negative currents, away from the tank floor, the riser's profile was a straight line whose inclination was such that the normal incident velocity was independent of the current speed when this exceeded about 0.5m/s. In these conditions the dimensionless peak frequency (based on the uniform normal incident velocity) was about 0.13.

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Section: Introductionmentioning

confidence: 99%

Laboratory measurements of the vortex-induced vibrations of an untensioned catenary riser with high curvature

Chaplin

King

2018

Journal of Fluids and Structures

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“…u is the horizontal wave velocity and can be estimated by linear wave theory, according to the study of (Wang et al, 2015b), which is…”

Section: Analytical Derivationmentioning

confidence: 99%

“…Thus, it is important to investigate the effect of time-varying tension on the riser’s dynamic motion. In practice, this fluctuating tension in risers is investigated as the parametric excitation and attracted much attention from researchers (Lei and Zheng, 2016; Prado et al, 2014; Wang et al, 2015a). In most previous studies (Chen et al, 2014; Hsu, 1975; Wang et al, 2015b), the dynamic response of risers was generally investigated based on regular wave and under an assumption that the tension fluctuation or top motion of the riser is harmonic, namely, single frequency harmonic excitation.…”

Section: Introductionmentioning

confidence: 99%

Dynamic analysis of parametrically excited marine riser under simultaneous stochastic waves and vortex

Xie

Mei

et al. 2018

Advances in Structural Engineering

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This study investigates the dynamic analysis of parametrically excited marine riser under simultaneous stochastic waves and vortex. A general analysis considers the parametric excitation resulting from platform motion, ocean wave loading directly on the rise, and vortex-shedding excitation due to flow bypassing the risers. Stochastic wave force and vortex excitation acting on the riser in the time domain is formulated by the stochastic phase spectrum method and derived by the linear-wave theory using a Pierson–Moskowitz wave spectrum to simulate real sea conditions. A derived parametrically excited top tensioned riser model subjected to simultaneous stochastic waves and vortex excitations is proposed. The efficacy of the present method is assessed by solutions obtained from other existing methods and experimental data of two test models. The present method is evaluated by solutions computed from existing methods and experimental data of two test models, and a general good agreement of the analyses between the proposed approach and other methods is observed. The availability of resonance, parametric stability, energy distribution and transfer, and the sensitivity of key parameters estimated by single-frequency and multi-frequency excitation are compared and discussed. Comparing with the results obtained from the harmonic excitation method, the present method can be used to make more reasonable and accurate calculations of the dynamic response of risers operating in real sea conditions.

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“…In this study, the linear hysteretic model [16,17] is applied to simulate the riser-seabed interaction, see Fig. 4.…”

Section: Riser-seabed Interaction Modelmentioning

confidence: 99%

“…This model is implemented into finite element (FE) software, ABAQUS by using subroutine UEL for the global analysis of the flexible riser. To simulate the riser-seabed interaction, a linearly hysteretic seabed model [16,17] is applied. Finally, parametric analyses in the installation plane are carried out to demonstrate the sensitivity of fatigue damage of helical wire near TDP to the seabed stiffness and interlayer friction.…”

Section: Introductionmentioning

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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Time domain approach for coupled cross-flow and in-line VIV induced fatigue damage of steel catenary riser at touchdown zone

Cited by 21 publications

References 16 publications

Laboratory measurements of the vortex-induced vibrations of an untensioned catenary riser with high curvature

Laboratory measurements of the vortex-induced vibrations of an untensioned catenary riser with high curvature

Dynamic analysis of parametrically excited marine riser under simultaneous stochastic waves and vortex

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

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