Abstract
In order to calculate fatigue strength of ship structure, the calculation of stress from wave loads and ship motion is needed. DIScrete Analysis Method (called DISAM for short) is an effective method for this. Using DISAM or other methods, the structural response which affect fatigue strength (e.g. combination of stress components, shape of long-term distribution of stress) is getting clarified. However, most of the studied are limited withinlongitudinal members, for example side longitudinals. First, in this study, the calculation using DISAM is carried out in order to investigate structural response of transverse members of double hulls VLCC, with respect to fatigue strength. The modeling techniques for load discretization and finite element meshing are explained. The results are shown for some members and summarized with stress at specified cumulative exceeding probability, correlation factor and Weibull shape factor. Second, the simplified method based of the obtained results is proposed for fatigue design of transverse members of double hulls VLCC. In the simplified method, the parameters which represent load characteristics are assumed same. The correlation factors and Weibull shape factors which are obtained by the analysis are used. The difference of structure is assessed with simple FEM calculation.
