Elastic Response Analysis of Large Floating Structures by Modal Synthesis Method

Abstract

In case of calculating the motions of ships and offshore structures in waves, the structures had been assumed as rigid bodies. However, we can't exclude the effects of elastic deformations on the motions of large floting structures such as a floting airport at sea, because of relative smal bending rigidity and low natunal frequencies. In this paper, we examined the motions of two floating structures joined with leaf spring by experiment and modal synthesis analysis, considering the effects of the elastic deformations of these structures. The reason why we use modal sysnthesis analysis is that we have advantages of reducing degrees of freedoms. Therefore, we can calculate responses earliear by using modal sysnthesis analysis althrough the object of our study has large degrees of freedoms. Another most important advantage is that we can express rigid motions and elastic vibrations in parallel.