2005 Fiscal Year Final Research Report Summary
Evaluation of fracture process by simultaneous measurement of acoustic and electromagnetic emission
| Project/Area Number |
15560082
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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 | Nihon University |
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Principal Investigator |
MORI Yasuhiko Nihon University, College of Industrial Technology, Professor, 生産工学部, 教授 (20059629)
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| Co-Investigator(Kenkyū-buntansha) |
OBATA Yoshihiko Nihon University, College of Industrial Technology, Associate Professor, 生産工学部, 助教授 (10139107)
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| Project Period (FY) |
2003 – 2005
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| Keywords | electromagnetic emission / acoustic emission / rock / deformation / in-situ stress / Kaiser Effect / international exchange / Czech Republic |
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| Research Abstract |
Electromagnetic emission (EME), which is emanated when the fracture of the dielectric materials occurs, may be applicable for evaluating the fracture process occurred inside the materials, as one of the new method. In order to investigate the applicability of the new method, in this study, the simultaneous measurement of EME and AE (Acoustic Emission) was conducted on the deformation tests of rock samples, so that the relationship between the generation of EME and the occurrence of micro fractures, which is estimated by AE, would be confirmed. The following conclusions could be drawn from the present study:
(1)EME generates only when the fresh surfaces due to cracking are created in the material.
(2)A model for explaining the EME generation has been established based on the dipole moment of electric charges distributed on the crack surfaces and the vibration of crack walls.
(3)Positive correlation between the signal amplitudes of EME and AE is found.
(4)EME may be useful tools for studying the fracture process occurred inside the materials.
(5)EME is very useful for estimating the rock in-situ stress, as a method in the field application.
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