Theoretical development and validation of a fatigue model for ship routing
Journal article, 2012

Fatigue cracks are observed much earlier than expected in ships and marine structures due to uncertainties in the fatigue design process, such as encountered sea environments and variability in S-N curves, etc. The current study presents the theoretical development and validation of a fatigue model useful for ship routing which may contribute to better utilisation of the materials and structures by more wise operation of them. During the theoretical development of the ship routing fatigue model, various models to estimate fatigue damage intensity, including both cycle counting calculations and spectral approximations, are reviewed. The proposed ship routing fatigue model is a function of operation profiles, i.e., heading angle and ship speed, as well as encountered wave environments (significant wave height), which are easily available in today’s commercial routing tool systems. Concerning the characteristics of ship response, the so-called narrow-band approximation is adopted and further simplified in order to estimate the fatigue damage in ships under an arbitrary stationary sea state. Long-term fatigue damage is estimated by a summation of fatigue damages in all encountered sea states during, for example, one voyage or a period of several years. Further, fatigue damage due to wave-induced vibrations (whipping and springing) and fatigue damage caused by various stress components are also studied and discussed. A validation using response from full-scalemeasurements and numerical analysis is presented. It shows that the proposed model works very well in comparison with the rainflow counting method. Finally, the proposed ship routing fatigue model is applied on real case scenarios, where its applicability in shipping industry is demonstrated.

spectral moments

rainflow counting


container vessels

narrow-band approximation


Wengang Mao

Chalmers, Shipping and Marine Technology, Division of Marine Design

Jonas Ringsberg

Chalmers, Shipping and Marine Technology, Division of Marine Design

Igor Rychlik

University of Gothenburg

Chalmers, Mathematical Sciences, Mathematical Statistics

Zhiyuan Li

Chalmers, Shipping and Marine Technology, Division of Marine Design

Ships and Offshore Structures

1744-5302 (ISSN) 1754-212X (eISSN)

Vol. 7 4 399-415

Chalmers Area of Advance Transport – funding 2012

Chalmers, 2012-01-01 -- 2012-12-31.

Subject Categories

Mechanical Engineering

Probability Theory and Statistics

Driving Forces

Sustainable development

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Basic sciences



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