Optimal Elastic Response and Design of Very Large Floating Structure

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A very large floating structures is a promising solution to satisfy the demand for flat land in Japan. Shallow waters suitable for reclamation have been already reclaimed, and deeper waters where reclamation is not easy must be utilized.The general dynamic response characteristics of a very large floating structure in the order of kilometers were analyzed and discussed using simplified numerical models. The models are of an anisotropic plate or beam on an elastic foundation. This modeling is a simple one but gives a general understanding and perspective of the elastic response characteristics of a very large floating structure. Based on the understanding obtained from this model, structural planning and design which utilize the advantages and avoid the disadvantages of the structure become possible.It was shown that the natural frequencies of the eigenmodes are higher than the natural heave frequency of the structure. The matching of the elastic mode and the spatial wave excitation pat … More tern, in addition to the coincidence of natural frequency and wave frequency, is necessary for the divergent resonance response. The characteristic length, which is a useful measure to juddge the deformation of the structure, is defined from the bending rigidity and the spring constant of the restoring force. For waves whose wavelength is longer than the characteristic length, the structure is relatively flexible and shows deformation on the wave slope. For waves of shorter wavelength than the characteristic length, the structure is relatively rigid and shows little deformation.A new pontoon type very large floating structure was proposed. The outer edge were modified and utilized as a control device to improve response characteristics of overall response of the structure. The improved response was confirmed by a series of calculations. The method of analysis used was to connect segmentally the analytical solutions of a uniform beam on an elastic foundation.The response of very large floating structure under take-off and landing loads of aircrafts was evaluated and the effect of interaction between the aircraft and the structure was discussed. The accuracy of calculation method was confirmed by experiment with small clastic experimental model. From the calculation, it can be said that net increase of resistance on the aircraft induced by the structure is very small. Less