Investigation on fatigue damage calibration factors in offshore structures. Issue 3 (2nd September 2021)

• Record Type: Journal Article
• Authors: Shabakhty, Naser; Haselibozchaloee, Danial; Correia, José A.F.O.
• Is Part Of: Proceedings of ICE. Volume 174:Issue 3(2021)
• Page Start: 65
• Page End: 80
• Publication Date: 2021-09-02
• Subjects: fatigue -- offshore engineering; Ocean engineering -- Periodicals; Coastal engineering -- Periodicals; 620.4162
• DOI: 10.1680/jmaen.2020.17
• Languages: English
• ISSNs: 1741-7597

Abstract

Abstract : Fatigue damage in marine structures is generally assessed by means of stress−number of cycles ( S − N ) curves. These curves are obtained from many experimental tests on structural components. Fracture mechanics (FM), using the crack propagation method is also a practical technique. In this approach, fatigue damage is estimated based on crack propagation from an initial crack size through the surface and depth of structural members. In this paper, S − N curves based on FM were compared with S − N curves obtained following two standards: DNVGL-RP-C203 and API-RP2A-WSD. The results showed that the curves did not agree well. Therefore, to obtain better fitting, calibration factors are needed. From S − N curves established for two stages, two calibration factors – α 1 (for the first stage) and α 2 (for the second stage) – are proposed for fitting S − N curves based on the FM approach with the DNV GL and the API S − N curves. The wall thickness, the initial crack depth and the critical crack depth were found to have a significant effect on determination of the calibration factors.