1988 Fiscal Year Final Research Report Summary
Preparation of Ultra-High-Temperature Push-Pull Thermal Fatigue Testing Equipment for Ceramics and Development of Evaluation Methods of their Strength.
| Project/Area Number |
62850021
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
材料力学
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| Research Institution | Kyoto University |
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Principal Investigator |
OHTANI Ryuichi Faculty of Engineering, Kyoto University, Professor, 工学部, 教授 (50025946)
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| Co-Investigator(Kenkyū-buntansha) |
村松 正光 東芝, 重電技術研究所, 主幹
KITAGAWA Masaki Metallurgy Department, Research Institute, Ishikawajima Harima Heavy Industries,, 技術研究所金属材料部, 課長
宇佐美 三郎 日立製作所, 機械研究所第3部, 主任研究員
NITTA Akito Nuclear Engineering Department, Central Research Institute of Electric Power Ind, 狛江研究所原子力部, 主査研究員
KITAMURA Takayuki Faculty of Engineering, Kyoto University, Instructor, 工学部, 助手 (20169882)
USAMI Saburo 3rd Department, Mechanical Engineering Research Laboratory, Hitachi, Senior Rese
MURAMATSU Masamitsu Metallurgical Engineering Department, Heavy Apparatus Engineering Lab., Toshiba,
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| Project Period (FY) |
1987 – 1988
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| Keywords | Ceramics / Ultra-high-temperature / Push-pull fatigue / Thermal fatigue testing equipment / Evaluation of high temperature strength / Small flaw / 信頼性評価 |
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| Research Abstract |
1. Push-pull thermal fatigue testing equipment was debeloped for evaluating the strength of ceramic materials at ultra-high-temperatures. The push-pull axis was specially aligned in order to avoid bending moment subjected to the ceramic specimen. Strain measurement was done by means of noncontact laser dimensional sensor (Ohtani).
2. High-temperature faituge tests were conducted by a similar testing machine of the push-pull type with different frames, heating system, and extensometer. It was proved that the test results on ceramics were coinside with those obtained from the debeloped equipment (Nitta).
3. It was found that the impact fravture strength of ceramics at high temperatures was not inferior to the static fracture strength. Also an estimating method of the ceramics strength was studied to find out the common property parameters independent of testing method and specimen shape and size (Muramatsu).
4. A reliable relationship betewwn fracture stress and small flaw size for ceramics was obtained, which was quite important and useful for evaluating the flaws in ceramics (Usami).
5. Stable crsck growth in ceramics was observed at high temperature during loading tests in a specially designed scanning electron microscope (Kitagawa).
6. Thermal fatigue tests were conducted on high-strength, low-ductility nickel base superalloys, and their failure analysis and the design of gas-turbines were practiced (Sakon).
7. A stochastic approach based on Monte Carlo simulation was preformed in order to clarify the behavior of small crack initiation and propagation in creep-fatigue condition. A probabilistic approach to the spacial distribution of creep cavities was also carried out for establishing a stochastic damage mechanics (Ohtani and Kitamura).
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