Research on the analysis of hydro-elastic behavior of a very large mobile offshore structure in waves and its anti-motion

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The following 3 topics have been mainly studied.1.Developement of a computer code for the analysis of hydrodynamic behaviorReview of the hydroelastic theory for a very large mobile offshore structure and the development of a computer code have been carried out. This code uses the p-FFT method, which enables to handle dozens of elastic modes with about 100,000 hydrodynamic panels in a practical CPU time. In addition, in order to simplify the input and output of the structural data and elastic modes computation, the combination of MSC NASTRAN and MSC PATRAN, which are popular commercial codes, is used. The interface between these commercial codes and the hydrodynamic code also has been developed. From the theoretical aspect, the code features that the consistency between the structural discretization and the hydrodynamic discretization is maintained so that the energy conservation between the wave making damping and the modal damping is satisfied.2.Validation of the computer codeA detailed convergence test of the code has been carried out and it is find that the code has enough convergence to carry out the computation of full scale structure. The effect of viscous damping has been investigated with the experimental data of the viscous damping. Comparisons between the numerical results and experimental data by NIES have been carried out, and it is confirmed that the numerical results have enough accuracy.3.Establishment of the analysis of the very large mobile offshore structureSummarizing overall results a concept of VLMOS has been presented. Using this concept for the simulation of navigation and electric power generation has been carried out. Through the simulation, it is confirmed that the methodology developed in this research is valid for conceptual design of VLMOS.