Study on Hydrodynamic Forces and Safety of Huge Floating Body

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 08045033
• Research Category: Grant-in-Aid for international Scientific Research
• Allocation Type: Single-year Grants
• Section: University-to-University Cooperative Research
• Research Field: 海洋工学
• Research Institution: Yokohama National University
• Principal Investigator: HIRAYAMA Tsugukiyo Yokohama National University, Faculty of Engineering, Professor, 工学部, 教授 (00018061)
• Co-Investigator(Kenkyū-buntansha): TACHIBANA Toshi-ichi University of SaoPaulo, Faculty of Engineering, Professor, 工学部, 教授 ; TAKAYAMA Takehiko Yokohama National University, Faculty of Engineering, Assistant, 工学部, 助手 (00303082) ; MA Nin Yokohama National University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (30251755) ; IKEHATA Mitsuhisa Yokohama National University, Faculty of Engineering, Professor, 工学部, 教授 (10114969) ; INOUE Yoshiyuki Yokohama National University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (60126373)
• Project Period (FY): 1996 – 1998
• Keywords: Very Large / Floating / Offshore Structure / Safety / Hydroelastic / Attitude Control

Research Abstract

For the utilization of ocean space, floating type very large offshore structures are taking into account today. A floating airport, which can resolve the problems of noise, limited land space and ecology, will be one example.
In order to realize such kind of very large offshore structure, safety and reliability in ocean environment including behavior in waves must be evaluated accurately. For that purpose, hydrodynamic external forces like wind, waves and current must be known exactly and hydro elastic characteristics of the floating body must be estimated and feed backed to the planning and design. This research is aiming at the evaluation of die external forces, hydro elastic responses, safety, reliability and attitude control of very large offshore structure based on the oil related floating offshore structures operated in Brazil. For this research, researchers are delegated each other, and operation of offshore structures and execution of experiments are searched each other. From the research, we could know the characteristics of hydrodynamic forces like interaction between columns and attitude control. About attitude control, we proposed pneumatic actuator. For the case of non-uniform actuator arrangement, the optimal control could give relatively good results by carrying out numerical simulation expressing elastic deformation by modal composition. Furthermore, the possibility of attitude control and its limitation were examined by carrying out model test using 7m length model.