2001 Fiscal Year Final Research Report Summary
Structural Investigation on Fuel Leakage of Cryogenic Fuel Tanks
| Project/Area Number |
11450375
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Aerospace engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
AOKI Takahira Graduate School of Engineering, The University of Tokyo, Associate Professor, 大学院・工学系研究科, 助教授 (00202466)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIKAWA Takashi National Aerospace Laboratory, Structures Division, Seciton Head (Researcher), 航空宇宙技術研究所・構造研究部, 室長(研究職)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Fuel tank / Laminate / Fuel leakage / Transverse crack / Reusable launch vehicle / CFRP / Cryogenics |
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| Research Abstract |
The successful development of the Reusable Launch Vehicles (RLV) depends on the drastic weight reduction of the vehicle based on the wide application of composite materials such as Carbon Fiber Reinforced Plastics (CFRP). The largest contribution to the structural weight reduction may be achieved by the utilization of composite tanks for cryogenic fuel that makes up more than 90 % of the gross launch weight. In the present study, the fuel leakage through the cascades of damages such as transverse cracks in the laminate is thoroughly investigated from the structural mechanics point of view. The experimental and analytical studies revealed the followings :
(1) The gas helium leakage was identified with the laminates containing transverse cracks in all of their layers, showing strong correlation between the applied load and leakage rate. The leakage was under negligible level with laminates with intact layers.
(2) Leakage was shown to be quantitatively predictable by employing the structural parameters including crack opening displacements and applied loads.
(3) Simple structural model for leakage paths construction was proposed and a scheme for accurate prediction of leakage under both mechanical and thermal loads was developed. The prediction method was then verified through the comparison with the experimental results employing biaxial cruciform laminate specimens and gas helium.
(4) The importance of using temperature dependent material properties for the predictions of mechanical or leakage behaviors was shown and emphasized.
With the results obtained herein, the fuel leakage through the laminates containing damages was shown to be predictable by the newly introduced structural model.
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