Spectral fatigue analysis of a ship structural detail – A practical case study

The fatigue life of a ship structural detail is calculated by using a spectral approach. The wave-induced vertical and horizontal bending moments, two base vessel loading conditions and the non-operating time have all been taken into account in the spectral fatigue damage calculation. The predicted fatigue life value by using the spectral approach is compared with the one calculated by using the IACS R 56, and various factors inducing uncertainties in the spectral method are further identified and investigated. Finally, recommendations on how to choose the specific parameters and how to model the random wave environment in the spectral approach are outlined.