1988 Fiscal Year Final Research Report Summary
Experimental Studies on Mechanical Properties of Structural Materials at Cryogenic Temperatures
| Project/Area Number |
61550529
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属材料(含表面処理・腐食防食)
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| Research Institution | University of Yamanashi |
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Principal Investigator |
TAKAAI Tetsuya Mechanical Engineering Department, Faculty of Engineering, Yamanashi University (Professor), 工学部, 教授 (80020460)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUSHIMA Akira Mechanical Engineering Department, Faculty of Engineering, Yamanashi University, 工学部, 助手 (90181255)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Aluminum and its alloy / GFRP Composite materials / Cryogenic temperatures / Mechanical properties / Temperature dependence / Microstructures / 破壊靱性 |
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| Research Abstract |
Mechanical properties of commercial pure aluminum, medium strength aluminum alloy and GDRP composite materials, usable at cryogenic temperature range as structural and functional materials, have been studied mainly in view points of tensile, tear fracture behaviors and Charpy impact fracture characteristics and fracture toughness at cryogenic temperatures ranging from 4 K to room temperature.
Effect of test temperatures on tensile, tear fracture and dynamic Charpy impact fracture characteristics of aluminum and aluminum alloys have shown some noticeable characteristic behaviors in accordance with microstructures and residual stresses existing by strain hardening.
The temperature dependence of the mechanical properties was effected mainly by the temperature dependence of the intermetallic compounds.
Typical laminated fracture was observed also for static tear fracture, however, only at below 20 K. The laminated fracture observed in static tear fracture showed no remarkable relations to the
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increase of the absorbed energy as in case of the Charpy impact fracture.
The tear fracture strength related almost linearly to 0.2 % proof stress measured by tensile test. No clear linearity was observed, however, between the ultimate tensile strength and tear fractrure strength at cryogenic.
The notch tensile ratios of holed and notched tensile specimens prepared from the GFRP composite materials were relatively higher by about 200 to 300 % as compared to with those of the estimated value on the basis of the stress concentration factor which was obtained on the ground of elastic theory and the notch shape and size of the tensile specimens, probably due to the stress relaxation at the epoxy reshin matrix in the neighborhood of the notched and holed portion of the tenesile specimens.
The measured maximum fracture stress of the GFRP composite materials was discussed applying the law of mixture and was compared with the calculated values based on the law of mixture. Both the measured and estimated values showed good agreement each other after modifying the previously measured values of the maximum fracture load of the glass fiber strand. Less
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Research Products
(18 results)
