2005 Fiscal Year Final Research Report Summary
NEW FINDING ON YIELDING IN AMORPHOUS POLYMERS AND ITS APPLICATION
| Project/Area Number |
16560064
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Kanazawa University, Graduate School of Natural Science and Technology |
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Principal Investigator |
KITAGAWA Masayoshi KANAZAWA UNIVERSITY, NATURAL SCIENCE & TECHNOLOGY, PROFESSOR, 自然科学研究科, 教授 (80007773)
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| Co-Investigator(Kenkyū-buntansha) |
YAMADA Yoshinori KANAZAWA UNIVERSITY, NATURAL SCIENCE & TECHNOLOGY, PROFESSOR, 自然科学研究科, 教授 (20126626)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Amorphous polymer / Yielding / Shear test / Quench / Slip line / Shear band / Fatigue crack growth / Striation |
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| Research Abstract |
It was pointed out previously that yield mode was very different between as-received (AR) and quenched (Q) amorphous polymers in a constant strain rate shear test. In AR samples, the yielding occurs by the initiation of slip lines and the nucleation and growth of shear bands (Intense shear band type). On the other hands, in Q samples, the yielding starts at the sudden initiation of vague plastic zone without slip lines and shear bands (Week shear band type). The stress-strain curves of both type of yielding are different. In order to investigate this difference of yield mode, these experiments such as observation of yield process, measurement of residual stress, effect of temperature and strain rate etc.have been performed using amorphous polymers PC,PVC and PET. It was shown that 1. the difference of the yield mode is not caused by the existence of residual stress, 2. the free volume increase resulted from quenching make polymer chains mobile easily leading to the yield mode difference. Furthermore, fatigue crack growth tests were executed using the AR and Q samples. It was shown that 1. the length of the plastic zone forming in front of the crack tip is coincident with the Dugdale equation in both AR and Q samples, 2. fatigue crack growth rates are nearly the same for both samples and 3.the shape of striation peculiar to fatigue crack growth is very different between both samples.
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