抄録
To determine design values of wave-induced responses, Fukuda's long-term prediction method is used on the basis of liner superposition theorem. However, when the effect of non-linearity is significant on a response, there is no well-formulated method for the estimation of design value. In this paper, a method to estimate severest sea conditions for a particular response of a ship or off-shore structure is proposed based on Fukuda's long-term prediction method. On the way, various wave statistics data are compared and examined from the viewpoint of the estimation of maximum response level in long term, and Hogben's new data is considered to give reasonable basis for this kind of study. Comparative calculations are made for vertical bending moment and lateral acceleration of a container ship and scaled ships of her. From the result, it is condidered that rational setting of severest sea conditions is possible by the proposed method, and that we can develop a new methodology to set design values of wave-induced responses by the analysis of short-term responses in the determined sea conditions. The author hopes, through the application of the proposed method, we can deal with design values of responses with significant non-linearity more easily, and we can establish better relationship between ship design and ship operation.
