On the prediction method of a hydroelastic responses of a VLFS considering a seabed topography

Abstract

In recent years, there are a lot of researches on hydroelastic responses of a Very Large Floating Structure (VLFS) which has several kilometers both in length and width. In the most of these researches, a geometric shape of the model is pontoon-type rectangle VLFS and it assumes that the sea depth is constant. But if we have a plan to construct such large structure in actual coastal area, it is quite difficult to find a vast flat bottom of the sea in Japan. So, in this paper we propose a prediction method on a hydroelastic behavior of VLFS extending the eigen functions expansion method to that including the sea bottom topographical effects. In the analyses the hydroelstic effect of the VLFS is also analyticaly taken into account. One of the improve points of the present method is that the problem of any supportive type of VLFS (i.e. pontoon supportive, column-supportive etc.) can be analyzed by this method. In other words, we can treat the pontoon type problem as a box-like shape column supportive type.Finally, some numerical results are carried out and discussions on the validity of the present method and the effects of seabed topography are made in this paper.