Fatigue damage sensitivity analysis of a naval high speed light craft via spectral fatigue analysis

ABSTRACT

Naval high speed light craft (HSLC) can be vulnerable to fatigue damage due to their lightweight scantlings and operation in sometimes harsh environments. Fatigue cracking can lead to costly repairs and reduction of operational availability. One fatigue analysis method is spectral fatigue analysis (SFA), which explicitly includes the operational profile and wave environment. However, typically, only linear loads are taken into account. Furthermore, fatigue analysis is influenced by the uncertainty in the input parameters and modelling procedure. This paper presents validation of SFA against trials data, followed by a study on the sensitivity of fatigue damage incurred in a naval HSLC to various parameters. It was found that the fatigue damage was most sensitive to the significant wave height, though when operational conditions were taken into account the relative importance of the speed and heading increased. The presented work is relevant to the through-life management of naval ship structures.

KEYWORDS:

• Spectral fatigue analysis
• naval high speed light craft
• marine-grade aluminium alloy
• sensitivity analysis

Acknowledgements

The assistance provided by the following individuals is acknowledged:

• Dr Roberto Ojeda, Australian Maritime College – University of Tasmania.

• Prof. Giles Thomas, University College London.

• Defence Science and Technology Group colleagues, including Mr Michael Brincat, Mr Peter Vincent, Mr Peter Graham, Dr Peter Dennis, Dr John Wharington, Mr Mario Selvestrel, Dr Seref Aksu, Dr Stuart Cannon, Mr Andrew Tynan, Ms Zenka Mathys, and Dr David Kershaw.

Disclosure statement

No potential conflict of interest was reported by the author.

ORCID

Teresa Magoga http://orcid.org/0000-0003-1636-264X