A B-Spline Type Direct Method for Predicting the Wave-Induced Motion of a Very Large Floating Structure

抄録

A B-spline type direct method is proposed in this study for predicting wave-induced hydroelastic motion of a very large floating structure. In the proposed method both the deflection of the structure and unknown pressure distribution are discretized with bi-cubic B-spline function. Hydrodynamic pressures due to the structural motion and incident waves are estimated by applying the pressure distribution method with Galerkin's scheme. The shape of the motion of each radiation freedom is given by the B-spline basis function, and the amplitudes of the radiation motions are determined by solving the Lagrange's equation of the structure that ensures the satisfaction of energyconservation principle. Comparisons between the calculations of the proposed method and experimental data have been carried out for the deflections and bending moment of a single structure, and it shows that the theoretical predictions and experimental results are in a very good agreement. In addition, the proposed method is applied to multiple elastic structures connected with beams. Again, the comparison of deflections of the structures and the bending moments of the beam connectors in various incident waves show good agreements between the calculations and experiments. The merits and demerits of the direct method and modal analysis method are also discussed.