0

Full Content is available to subscribers

Subscribe/Learn More  >

Viscoelastic Analysis of Bend Stiffeners

[+] Author Affiliations
Marcelo Caire, Murilo Augusto Vaz

COPPE/Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil

Carlos Alberto Duarte de Lemos

PETROBRAS, Rio de Janeiro, RJ, Brazil

Paper No. OMAE2005-67321, pp. 531-538; 8 pages
doi:10.1115/OMAE2005-67321
From:
  • ASME 2005 24th International Conference on Offshore Mechanics and Arctic Engineering
  • 24th International Conference on Offshore Mechanics and Arctic Engineering: Volume 3
  • Halkidiki, Greece, June 12–17, 2005
  • Conference Sponsors: Ocean, Offshore and Arctic Engineering Division
  • ISBN: 0-7918-4197-9 | eISBN: 0-7918-3759-9
  • Copyright © 2005 by ASME

abstract

Bend stiffeners are polymeric structures employed to ensure a smooth and safe transition in the upper connection of risers and umbilical cables, protecting them against accumulation of fatigue damage and excessive curvatures. Recent failures have stimulated a better understanding of the mechanical response in order to increase the reliability in design and analysis of bend stiffeners. This work presents a mathematical formulation that represents the system riser/bend stiffener considering geometric non linearity and polyurethane with viscoelastic behaviour, an inherent characteristic to polymers. The following assumptions are considered: cross-sections remain plane after deformation, large deflections are accepted but it is a small strain bending problem, the self-weight and external forces are disregarded and the material is assumed with linear viscoelastic behaviour. The curves that represent the viscoelastic response of the material have been raised by means of creep tests, whose specimens were cut from actual bend stiffeners. The time dependent data obtained in the experimental tests were well approximated by a third order Prony series which describes the creep function. The set of four first order non linear ordinary differential equations results from geometrical compatibility, equilibrium of forces and moments and linear viscoelastic constitutive relations. The numerical solution of the problem is obtained using a one-parameter shooting method. The results are then compared with the consolidated numerical solution for linear elastic material. It is concluded that the viscoelastic phenomena can lead to excessive curvatures on the upper terminations of risers and umbilical cables if the polymeric structure were designed considering elastic behaviour. The correct characterization of the viscoelastic properties of polyurethane used on bend stiffeners must be taken into account when accurate analysis is desired.

Copyright © 2005 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In