Corrosion fatigue crack growth mechanisms in offshore monopile steel weldments

O. Adedipe, F. Brennan, A. Mehmanparast, A. Kolios, I. Tavares

Research output: Contribution to journalArticle

13 Citations (Scopus)
26 Downloads (Pure)

Abstract

Offshore structures are generally fabricated of welded joints, which are considered as potential spots for crack initiation owing to the degree of stress concentrations imposed by the weld geometry and the effects of residual stresses introduced by welding processes. There are significant numbers of the current and anticipated offshore installations coupled with the use of newer materials and fabrication techniques. It is therefore important to understand the crack growth mechanisms in these structures accompanied with the effects of mean or residual stresses for a safe estimation of their service lives. In this paper, crack growth results of HAZ and weld materials similar to those used for offshore installations are presented. Tests were conducted in air and in simulated free-corrosion conditions at loading frequencies of 0.3 Hz in seawater, 5 Hz in air and at loading ratios of 0.1, 0.5 and 0.7. Results showed that crack growth rates were influenced by mean stresses, materials microstructure accompanied by welding procedure and environment. Crack growth results showed good agreement when compared with those obtained from other steels used for offshore structures.

Original languageEnglish
Pages (from-to)1868-1881
Number of pages14
JournalFatigue and Fracture of Engineering Materials and Structures
Volume40
Issue number11
Early online date20 Apr 2017
DOIs
Publication statusPublished - 1 Nov 2017

Keywords

  • crack growth rates
  • free-corrosion
  • HAZ
  • mean stress
  • weld

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