Abstract
In the near future, "huge" floating structures, such as floating airports, which became far larger in size than the existing ones, seem to be brought into existence. In wave response analysis of these structures, it may be necessary to analyse the motion as rigid body while taking also account of the elastic vibration. The object of this study is to establish the theoritical calculation method so that we must understand the characteristics of wave-induced motion and vibration for huge floating structures. In this report, as a first step, the authors have applied the finite element method to the dynamic interaction problem of the fluid-elastic beam system, and investigated wave-induced motion and vibration taking account of frequency dependency of the hydrodynamic forces. Finally the experiment and calculation results were compared with each other, and good agreement obtained. As a result of the above, the following points were cleared that (1) this method is reasonable for vertical displacement, (2) in case of the huge floating structures, the effects of elasticity should not be neglected, (3) the effects of coupling among the modes to low frequency region should be taken sufficiently into consideration.
