Fatigue is often the governing criterion for deepwater riser design. Fatigue assessment methods based on SN curves typically use fatigue safety factors and there is a lack on consensus about the appropriate Design Fatigue Factor (DFF) for VIV that should be applied. A DFF of 20 is commonly used in project specifications to account for a larger uncertainty in prediction of fatigue damage due to VIV, i.e. fatigue life due to VIV should be at least 20 times more than the service life of the riser. Recent case studies and benchmarking assessments, have confirmed that the DFF of 20 for VIV is not always an optimal choice. Owing to the complexity of the VIV problem, often semi-empirical solutions are adopted in the riser VIV analysis. The implicit uncertainty and bias associated with the VIV analysis model, needs to be considered along with the VIV fatigue safety factor, in order to establish the adequate acceptance criterion for VIV induced fatigue. The stochastic variables governing the VIV and their associated uncertainties can vary widely from case to case and this in turn will influence the VIV safety factor. Different stochastic variables may be relevant based on the floater type, riser type, environmental modeling, analysis methodology etc. In addition to these stochastic variables, the uncertainty in the VIV specific variables, such as Strouhal number, bandwidth parameters, damping effects, lift coefficient, response models (Amplitude /Diameter ratio), etc also need to be considered in the evaluation of the VIV safety factor. In this paper, guidance is provided by means of case studies for establishing case specific VIV safety factors. By performing a set of dedicated analyses for the prevailing uncertain input parameters, the resulting uncertainty in the VIV fatigue damage is estimated. The enhanced risk based criterion presented in DNV Recommended Practice RP-F204 [7], developed as part of the Norwegian Deepwater Programme (NDP) is applied for these case studies to calculate the required VIV fatigue safety factors. This project was sponsored by NDP, whose contribution and support is gratefully acknowledged.
Skip Nav Destination
ASME 2005 24th International Conference on Offshore Mechanics and Arctic Engineering
June 12–17, 2005
Halkidiki, Greece
Conference Sponsors:
- Ocean, Offshore and Arctic Engineering Division
ISBN:
0-7918-4195-2
PROCEEDINGS PAPER
Application of DNV-RP-F204 for Determining Riser VIV Safety Factors
Muthu Chezhian,
Muthu Chezhian
Det Norske Veritas, Ho̸vik, Norway
Search for other works by this author on:
Marit Ronæss,
Marit Ronæss
Det Norske Veritas, Ho̸vik, Norway
Search for other works by this author on:
Trond Stokka Meling
Trond Stokka Meling
Statoil, Stavanger, Norway
Search for other works by this author on:
Muthu Chezhian
Det Norske Veritas, Ho̸vik, Norway
Kim Mo̸rk
Det Norske Veritas, Ho̸vik, Norway
Marit Ronæss
Det Norske Veritas, Ho̸vik, Norway
Trond Stokka Meling
Statoil, Stavanger, Norway
Paper No:
OMAE2005-67021, pp. 57-63; 7 pages
Published Online:
November 11, 2008
Citation
Chezhian, M, Mo̸rk, K, Ronæss, M, & Meling, TS. "Application of DNV-RP-F204 for Determining Riser VIV Safety Factors." Proceedings of the ASME 2005 24th International Conference on Offshore Mechanics and Arctic Engineering. 24th International Conference on Offshore Mechanics and Arctic Engineering: Volume 1, Parts A and B. Halkidiki, Greece. June 12–17, 2005. pp. 57-63. ASME. https://doi.org/10.1115/OMAE2005-67021
Download citation file:
13
Views
0
Citations
Related Proceedings Papers
Related Articles
Characteristic Analysis of VIV-Induced Fatigue Damage of Top Tensioned Risers Based on Simplified Model
J. Offshore Mech. Arct. Eng (May,2011)
Assessment of Fatigue Safety Factors for Deep-Water Risers in Relation to VIV
J. Offshore Mech. Arct. Eng (November,2005)
Applicability of Equivalent Constant Amplitude Loading for Assessing the Fatigue Life of Pipelines and Risers and the Influence of Compressive Stress Cycles
J. Pressure Vessel Technol (April,2013)
Related Chapters
Materials
Design and Application of the Worm Gear
Developing Human Performance Measures (PSAM-0207)
Proceedings of the Eighth International Conference on Probabilistic Safety Assessment & Management (PSAM)
Analysis of Components in VIII-2
Guidebook for the Design of ASME Section VIII Pressure Vessels, Third Edition