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Analysis of Elastic Response of Very Large Floating Structures with Discontinuous Stiffness in Waves - Study on the Modeling of Joint Part -

Publication year

Port and Airport Research Institute　Technical Note　1135　2006.06

Author(s)

Tsutomu MOMOKI,Haruo YONEYAMA,Tetsuya HIRAISHI

Department
/Divison

Geotechnical and Structural Engineering Department Offshore Structures Division

Executive Summary

Recently, very large floating structures (VLFS) are proposed for use as an airport, disaster prevention basis and offshore wind power generation system, and so on. There are a lot of researches on hydrodynamic response of the VLFS in waves. However, it is necessary to research the influence of the discontinuity of the stiffness when the floating units of different types are connected with each other or the joints of floating units have a special shape.
　In this research, we conducted the hydraulic model experiment on 1/50 scale, and analyzed the elastic response of the test model. The test model consists of many units. Since the joint part is made from aluminum components and bolts, it is difficult to obtain an exact solution from a traditional technique. We performed numerical analysis using VODAC (Very Large Floating Structure Oriented Dynamic Analysis Code) developed by University of Tokyo. Two kinds of beam FE-models are employed as a structural model; one is the model that arranges equivalent beam elements on the neural plane, and the other the model that represents the deck, bottom and vertical wall using beam element individually.
　We got that a stiffness change of floating body by joint part reduced the accuracy of the numerical analysis that used the equivalent beam elements model. In addition, we showed that the numerical analysis of high accuracy was possible by using a three-dimensional beam elements model.

PDF File

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