An absolute coordinate formulation for three-dimensional flexible pipe analysis

Chai, Young-Suk; Varyani, K.S.

doi:10.1016/j.oceaneng.2005.04.006

Cited by 62 publications

(22 citation statements)

References 11 publications

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“…The relationship between these two kinds of tension can be found in Eq.(8). In the present simulation results, the bottom node effective tension is 1575.8 kN; after converting to the riser actual wall tension one gets 1066.9 kN, and again excellent agreement is obtained with Chai and Varyani (2006).…”

Section: A Simple Steel Catenary Risersupporting

confidence: 80%

“…The static effective tension and bending moment distribution are plotted in Fig.9. It can be seen that the magnitude of top node effective tension and the peak bending moment at the touch down point are quite similar to that given by Chai and Varyani (2006). Note that Fig.9 plotted the effective tension rather than the riser actual wall tension.…”

Section: A Simple Steel Catenary Risersupporting

confidence: 69%

“…The maximum deflection in y-axis is 25.9 m, relatively larger than that of Chai and Varyani (2006), which is approximately 21m. The difference can be attributed to the absence of torsional stiffness in the present rod model, and through this comparison one can find that the torsional stiffness plays a negligible role in riser's modeling, and that its neglect leads to a relatively conservative result.…”

Section: A Simple Steel Catenary Risermentioning

confidence: 80%

“…Lumped mass (Ghadimi,1988) Theory (Ghadimi,1988 A steel catenary riser partially grounded on flat and horizontal seabed, similar to Chai and Varyani (2006), is used in this numerical example and its geometric and material properties are given in Table 1. The top and bottom ends are assumed to be pinned, and no torque is considered.…”

Section: Presentmentioning

confidence: 99%

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Nonlinear analysis of flexible and steel catenary risers with internal flow and seabed interaction effects

Chen

Guo

2011

J. Marine. Sci. Appl.

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Flexible risers and steel catenary risers often provide unique riser solutions for today's deepwater field development. Accurate analysis of these slender structures, in which there are high-speed HP/HT internal flows, is critical to ensure personnel and asset safety. In this study, a special global coordinate-based FEM rod model was adopted to identify and quantify the effects of internal flow and hydrostatic pressure on both flexible and deepwater steel catenary risers, with emphasis on the latter. By incorporating internal flow induced forces into the model, it was found that the internal flow contributes a new term to the effective tension expression. For flexible risers in shallow water, internal flow and hydrostatic pressure made virtually no change to effective tension by merely altering the riser wall tension. In deep water the internal pressure wielded a dominant role in governing the riser effective tension and furthering the static configuration, while the effect of inflow velocity was negligible. With respect to the riser seabed interaction, both the seabed support and friction effect were considered, with the former modeled by a nonlinear quadratic spring, allowing for a consistent derivation of the tangent stiffness matrix. The presented application examples show that the nonlinear quadratic spring is, when using the catenary solution as an initial static profile, an efficient way to model the quasi-Winkler-type elastic seabed foundation in this finite element scheme.

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Section: A Simple Steel Catenary Risersupporting

confidence: 80%

Section: A Simple Steel Catenary Risersupporting

confidence: 69%

Section: A Simple Steel Catenary Risermentioning

confidence: 80%

Section: Presentmentioning

confidence: 99%

See 2 more Smart Citations

Nonlinear analysis of flexible and steel catenary risers with internal flow and seabed interaction effects

Chen

Guo

2011

J. Marine. Sci. Appl.

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“…An extensive discussion on the state of the art in modeling and on problems in total dynamic analysis of offshore systems is presented by Chakrabarti [5]. Although Patel and Seyed [6] report many different modelling methods, the most popular methods used are the lumped mass [7,8] and the finite element methods [9][10][11]. Those methods are used in commercial packages not only specialized in offshore engineering (Riffex, Orcaflex or Offpipe) but also of general use such as Abaqus.…”

Section: Introductionmentioning

confidence: 99%

Compensation of top horizontal displacements of a riser

et al. 2016

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The nonlinear dynamic problem of catenary risers is solved by means of the rigid finite element method. The method enables us to model slender systems such as lines, cables and risers undergoing large base motions. The formulation allows elimination of large values of stiffness coefficients: shear, longitudinal and torsional (dependent on permissibility of the system analyzed). The analysis presented in the paper is concerned with the dynamics of a riser initially bent and undergoing heave excitation. Comparison of the results with those obtained using the finite difference and finite element methods shows good compatibility and indicates the correctness of the models obtained by means of the rigid finite element method. Numerical effectiveness of the method enables it to be applied in solving the dynamic optimization problem. The problem described is the compensation of the horizontal vibrations of the vessel or a platform by vertical displacements of the upper end of the riser. Bending moments which arise during the motion of a platform or a vessel can seriously influence and in some cases damage the structure. Thus the aim of the optimization is to ensure that the maximum bending moment at a given point does not exceed its static counterpart. The results of numerical simulations show that the systems enabling heave compensation can be used to minimize the difference between the bending moment caused by displacements of the platform or a vessel and the static moment.

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3D Rod Theory for Static and Dynamic Analysis

2021

Deepwater Flexible Risers and Pipelines

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An absolute coordinate formulation for three-dimensional flexible pipe analysis

Cited by 62 publications

References 11 publications

Nonlinear analysis of flexible and steel catenary risers with internal flow and seabed interaction effects

Nonlinear analysis of flexible and steel catenary risers with internal flow and seabed interaction effects

Compensation of top horizontal displacements of a riser

3D Rod Theory for Static and Dynamic Analysis

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