Random Fatigue Analysis of Container Ship Structures

• Main Author: Wengang Mao
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2009
• Subjects: North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.158.9267; http://www.math.chalmers.se/Math/Research/Preprints/2009/22.pdf

The work presented in this thesis concerns the fatigue estimation model and the corresponding uncertainties for container vessels based on both onboard measurement and theoretical analysis. The fatigue model developed is based on the generalized narrow band approximation, where the significant response height is shown to have a linear relation with the corresponding significant wave height Hs, and the zero up-crossing response frequency, fz, is represented by the encountered wave frequency also in terms of Hs. It is then validated by the measurement from the onboard hull monitoring system of a 2800 TEU container vessel operated in the North Atlantic. Considering that the model is strongly dependent on the Hs, we also calibrated the Hs measurement from onboard system using different types of satellite measurement. It shows that there is about a 25 % overestimation from the onboard measurement system, which coincided well with the captain’s report. Based on such calibration, the fatigue model is then improved with a less than 10 % bias with regard to the “accurate” rainflow estimation for all 14 voyages measured during 2008. The uncertainty in using the proposed fatigue model, as well as the other general