Write your message
Volume 3, Issue 5 (3-2007)                   Marine Engineering 2007, 3(5): 1-22 | Back to browse issues page

XML Persian Abstract Print


Download citation:
BibTeX | RIS | EndNote | Medlars | ProCite | Reference Manager | RefWorks
Send citation to:

Rashed G, Ghajar R, Hashemi S J. **Influence of Drillship Roll on The Drillpipe Fatigue Under Variable Amplitude Loading . Marine Engineering 2007; 3 (5) :1-22
URL: http://marine-eng.ir/article-1-30-en.html
1- Khaje Nasir Toosi University of Technology
2- Petroleum Industry University
Abstract:   (17185 Views)

During the offshore drilling operations by drillships or semisubmersible vessels the drillstring in its first drilljoint to the Kelly suffers bending due to float vessel roll or pitch. The cyclic bending stress at any point along the drillstring, is a function of the roll or pitch angle, Kelly position in bushing, and hookload. The cumulative fatigue damage of the drillpipe due to cyclic stresses near the drillpipe connection to Kelly has been calculated in this paper. The effects of the cyclic stress amplitude variation are also taken into account. Then five multiaxial fatigue models are evaluated under variable amplitude loading (similar to drillpipe loading) conditions. Comparing the results of the five models predictions by the muliaxial fatigue tests experimental data under variable amplitude axial-torsional loading, show that the combined critical plane and energy models predict the fatigue life better than the others. It works much better for variable amplitude loading than the existing models.

Full-Text [PDF 2278 kb]   (2605 Downloads)    
Type of Study: Research Paper | Subject: Offshore Structure
Received: 2010/07/17 | Accepted: 2013/10/19

Rights and permissions
Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Creative Commons License
International Journal of Maritime Technology is licensed under a

Creative Commons Attribution-NonCommercial 4.0 International License.