In this paper, three-dimensional linear hydroelastic theory has been used to study the dynamic response of box-typed VLFS in waves. Beam and three-dimensional FEM model are employed respectively to describe the dynamic characteristics of the box-typed structure in vacuum. And the same hydrodynamic panel model is applied to get the effect of different dry models on the hydroelastic behavior of box-typed structure. In order to validate the three-dimensional linear hydroelasty theory, a hydroelastic model experiment has also been carried out in the State Key Laboratory of Ocean Engineering at Shanghai Jiao Tong University. There is quit a good agreement between the calculated results and that of experiment.
Recently, the prospective potential applications of very large floating structure to utilization of ocean space and exploitation of ocean resource have become one of important research subjects of ocean engineering filed in many countries. However, due to the horizontal scales of box-typed VLFS are very large in proportion to the relatively small thickness, the relative rigidity of this structure is greatly decreased and the hydroelastic behavior of the structure in waves must be considered. In this paper, three-dimensional linear hydroelastic theory is used to calculate the hydroelastic behavior of box-typed very large floating structure in waves. Three-dimensional finite element model and beam models are applied respectively to carry out the dry model analysis to obtain the dynamic characteristics of this structure in vacuum. The wetted surface of the structure is disposed as a set of discrete panels, on each of which there is a source. By utilization of the orthogonality between principal modes of dry structure and mode analysis of structure vibration, the mode analysis equation of floating structure in wave can be obtained while the interaction between fluid and structure can be realized by matching corresponding boundary conditions (Wu, 1984).