| Project/Area Number |
06044184
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Kumamoto University |
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Principal Investigator |
TAKASHIMA Kazuki Faculty of Engineering, Kumamoto University, Associate Professor, 工学部, 助教授 (60163193)
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| Co-Investigator(Kenkyū-buntansha) |
PONTON Clive b Faculty of Engineering, The University of Birmingham, 工学部, 講師
BOWEN Paul Faculty of Engineering, The University of Birmingham, 工学部, 教授
KNOTT John f Faculty of Engineering, The University of Birmingham, 工学部, 教授
HIGO Yakichi Precision and Intelligence Laboratory, Tokyo Institute of Technology, 精密工学研究所, 教授 (30016802)
TONDA Hideki Faculty of Engineering, Kumamoto University, 工学部, 教授 (90040386)
CLIVE B.Pont バーミンガム大学, 工学部, 講師
PAUL Bowen バーミンガム大学, 工学部, 上級講師
JOHN F.Knott バーミンガム大学, 工学部, 教授
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥7,100,000 (Direct Cost: ¥7,100,000)
Fiscal Year 1995: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1994: ¥4,100,000 (Direct Cost: ¥4,100,000)
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| Keywords | Composites / Fracture / Fatigue / Damage Evaluation / Elastic Modulus / Internal Friction / Non-Destructive Inspection / Acoustic Emission |
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| Research Abstract |
Damage evolution in a SiC fiber reinforce Ti alloy composite (SCS-6/Ti-6Al-4V) has been assessed by modulus loss, change in internal friction (mechanical damping) and acoustic emission (AE). Damage was introduced into unidirectionally reinforced unnotched specimens by four point bending using constant cyclic amplitude loading. Dynamic Young's modulus and internal friction were measured by a flexural resonant method after a predetemined number of cycles, and AE signals were also monitored during the tests. Damage induced in the composites changed progressively primarily as a function of the applied maximum stress levels (sigma_<max>). Fiber fracture dominated at sigma_<max> values greater than 0.5sigma_B (where sigma_B is the flexural streength of the composite). High smplitude AE signals associated with fiber fracture were observed, and internal fiction measurements increased rapidly just before failure of the specimen. In contrast, matrix cracking dominated at sigma_<max> values lower than 0.35 sigma_B. As matrix cracks (bridged by intact fibers) grow in these composites, internal friction measurements increase. Small amplitude AE signals were observed to be associated with matrix crack grwth. Also, fiber fracture occurred in the bridged zone at sigma_<max> values between 0.35 and 0.5sigma_B. In all tests, the Young's modulus decreased by only 1% of its initial value until just before failure of the specimen. However, internal friction measurement increased repidly prior to catastrophic failure of specimen at all stress levels investigated in this study. This result shows that an increase in internal friction is related to damage accumulation in the composites, and suggests that measurement of changes in internal friction may be applicable to the assessment of damage in such composites.
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