1987 Fiscal Year Final Research Report Summary
Study on the deformation and strength of composite materials under impact loading
| Project/Area Number |
61460078
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Aerospace engineering
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| Research Institution | Kyoto University |
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Principal Investigator |
TANAKA Kichinosuke Kyoto University, Faculty of Engineering, Professor, 工学部, 教授 (90025792)
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| Co-Investigator(Kenkyū-buntansha) |
NOJIMA Taketoshi Kyoto University, Faculty of Engineering, Instructor, 工学部, 助手 (40026258)
OGAWA Kinya Kyoto University, Faculty of Engineering, Instructor, 工学部, 助手 (00026220)
SHIMA Susumu Kyoto University, Faculty of Engineering, Professor, 工学部, 教授 (70026160)
KUROKAWA Tomoaki Kyoto University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (80127076)
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| Project Period (FY) |
1986 – 1987
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| Keywords | CFRP / graphite / epoxy composite laminate / impact / delamination |
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| Research Abstract |
It has been pointed out that the strength after impact damage for advanced composite laminates is very important. From this point of view, mechanical behavior and delaminations of graphite/epoxy composite laminates under normal impact were investigated in this study.
At first, the dynamic Young's modulus was measured using the pulse-propagation method and the free vibration method through the composite laminate. The value was compared with the static value and significant differences were not recognized.
Next, the dynamic bending tests of composite laminate specimens were carried out with the Hopkinson bar technique. The items which should be considered in more detail were clarified. At last, Mechanical behaviors of [0゜/90゜/45゜/-45゜]_s laminate under normal impact were investigated experimentally and theoretically. Transient histories of deflection, strains and impact force were measured and compared with calculated histories. The measured values showed bood agreement with the theoretical ones. Delaminations were detected both non- destructively with a SAM (scanning acoustic microscope) and destructively by fluorescent- penetrant inspection. It was made clear that delaminations occur only at interfaces where neighboring fiber directions are orthogonal.
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