Analysis Of Hydroelastic Responses Of Very Large Floating Structure (VLFS) By Use Of Plate Model

It is particular when solve the hydrodynamic characteristic of the Very Large Floating Structure (VLFS). As the VLFS is a long, huge and thin flexible structure, its hydrodynamic response in waves is a typical problem of fluid-solid coupling and it cannot be counted as a rigid body. The hydroelastic theory can be carried for the qualitative analysis or the quantitative analysis with the load, motion, distortion and internal force in unification of the object which has random shape, and it represents the applicability in describing the problem of fluid-solid coupling. So, it is used widely in solving the VLFS. However, the mathematical models which used for calculating and analyzing with high-precision generally have extremely huge workload. In order to acquaint the macroscopical characteristic of the hydroelastic response of the VLFS, a simple mathematical model is set up and twodimensional potential flow theory in fluid part and twodimensional plate theory in structure part are employed. By using this simple model, the quantity of calculation can be reduced notably, then catch the qualitative characteristic response of VLFS by and large.Based on the hydroelastic response theory, the motions of the VLFS are analyzed in the dissertation, and then the velocity potential of fluid and the velocity potential of deflection wave of VLFS are solved. The responses of VLFS are analyzed and the formula of calculating the refraction index of VLFS is derived. Then, the formula of the hydroelastic response amplitude is derived based on the equations of the conservation of energy flux.The method and the calculating program in this dissertation are validated by the calculating models. The results of calculation represent that the method and the program can be used to estimate the deflection distortion of VLFS when the incident waves are oblique waves.Finally, a wave spectrum is introduced to calculate the hydroelastic responses of VLFS under general wave conditions as a tentative application. Consequently, thequalitative characteristic response of VLFS can be found out under irregular wave conditions.