2006 Fiscal Year Final Research Report Summary
Study on optimal structure used for offshore wind turbine facilities
| Project/Area Number |
17560432
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural engineering/Earthquake engineering/Maintenance management engineering
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| Research Institution | Tokai University |
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Principal Investigator |
SEKITA Kinji Tokai University, School of Marine Science and Technology, Professor, 海洋学部・教授, 教授 (90287045)
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| Co-Investigator(Kenkyū-buntansha) |
YAGO Kiyokazu National Maritime Research Institute, Marine Div., Assistant Professor, 海洋開発研究領域, 助教授 (50399515)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Wind force / Renewable energy / Offshore space utilization / Structural engineering / Dynamic effects / Seismic resistance |
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| Research Abstract |
So as to expand offshore wind farms emerging around North-West Europe into Japan, we have to cope with natural environmental conditions such as severe typhoons, earthquakes, the soft seabed and steep bathymetry peculiar to our country. Substructures of a wind turbine should have due rigidity and strength with the configuration as to ward off wind loads. Since fluctuating winds, waves and various mechanical vibrations are acting on them, resonance evasion, reduction of those excitation and fatigue damage are required. So we have proposed a steel tube truss alternative to a conventional steel cylindrical tower for fixed bottom or floating facilities. To confirm the applicability, we carried out design of both substructures onto a 5MW wind generator, a wind tunnel model experiment and numerical study taken the pile and soil interaction into consideration. Finally, we concluded as follows ;
1)The substructures made of a truss tower composed of small number of members having small diameter a
… More
nd jacket is better than a cylindrical tower and monopile. Although the weight of steel materials is larger about 1.7 times, the flexural rigidity is appropriately 1.5 times. This implies that proposed substructure takes advantage from the fatigue perspective.
2)The first natural period of 2.5s obtained by the eigenvalue analyses can be longer than the period of 1.0-2.0s that a rotating blade intersects the tower, and shorter than rotating period of 3.0-6.0s. These periods pertaining to tower shadow effects due to wake bring varying member forces. Thereby, the optimal design avoiding the resonance from the natural period of the facility may be done.
3)The measured out-of-plane accelerations and oscillation loads in the truss tower were smaller than those of the cylinder tower. The electricity generated by the truss tower is slightly larger.
4)The truss tower with jacket foundation has enough ductility, such that it can deform four or five times during collapse compared with the deformation at yielding by a pushover analysis. Less
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Research Products
(8 results)
