| Project/Area Number |
15560699
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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 |
Earth system and resources enginnering
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| Research Institution | Muroran Institute of Technology |
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Principal Investigator |
ITAKURA Ken-ichi Muroran Institute of Technology, Department of Computer Science and Systems Engineering, Professor, 工学部, 教授 (20168298)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Kazuhiko Muroran Institute of Technology, Department of Computer Science and Systems Engineering, Professor, 工学部, 教授 (30002009)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2003: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Micromechanics Tests / Micro-specimen / Crack Growth / Complexity / Visualization / Discrete Element Method / DEM / Simulation |
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| Research Abstract |
A micromechanics test was carried out to elucidate crack growth and investigate the influence of structural complexity in rock specimens with rock strength. That test is a loading test on a microscope stage using small specimen (5×6×1mm). Benefits of this test are that it readily depicts the structural configuration of rock components of rock specimens. It is also easy to visualize the growth of cracks passing through the specimen. After micromechanics tests, fracture simulations using discrete element method (DEM) were conducted using obtained data.
The following salient results were obtained :
1.Small specimens were prepared from a granite block in three orthogonal directions (H, G and R). Microscopic observation showed that each specimen had a dominant orientation of pre-existing cracks. Tensile strength and its strain were highest in the H specimen and lowest in the R specimen, as shown also by results obtained from usual tensile tests.
2.Tensile strength values from micromechanics tests are smaller by about 17% than those from conventional tensile tests.
3.Visualization of crack growth shows that a pie-existing crack is an onset of tensile crack growth in the R specimen. The shear crack slides before rupturing in G and H specimens.
4.The complexity of the configuration in black-mica influenced the tensile strength of the granite specimen. That is, the higher the complexity index becomes, such as that of the fractal dimension of the black-mica outline, the smaller the tensile strength is.
5.Fracture simulation of DEM for a 3D specimen model including pie-existing cracks shows that a similar tendency of tensile strength and its strain are obtained from micromechanics tests for H, G, and R specimens.
6.The fracture process and fragmentation differed depending on the orientation of pre-existing cracks in the model specimens.
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