| Project/Area Number |
05650083
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
NAGAKI Shigeru OKAYAMA UNIVERSITY,DPEARTMENT OF MECHANICAL ENGINEERING,ASSOCIATE PROFESSOR, 工学部, 助教授 (30135959)
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| Co-Investigator(Kenkyū-buntansha) |
NOSHO Takayoshi OKAYAMA PREFECTURAL UNIVERSITY,DEPARTMENT OF INFORMATION SCIENCE,LECTURER, 情報工学部, 講師 (80208298)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1994: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1993: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Plasticity / Couple stress theory / Constitutive equation / Microstructure / Porous material / Anisotropic yield function / Perforated sheet |
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| Research Abstract |
Directors and slip vectors were introduced to the theory of plastic materials with microsturcutes in the rage of the finite deformation. The relation between the proposed theory and the couple stress thory of elasticity together with the higher order strain gradient theory was discussed thoretically. The constitutive relation considering couple stress for plastic materials was also developed and an example of the rate-type constitutive equation was derived, where the yeild condition depends on not only the usual Cauchy stress but also the couple stress.
To obtain the further mathematical form of constitutive equations for the real material with microstructures, we adopted the material with voids (i.e.porous material) as a model of materials with microstructures and the elastic-plastic behavior of perforated sheets were investigated experimentally.
The yield stresses of perforated sheets with quasi-randomly distributed holes experimentally obtained can be simulated in the first approximation by the anisotropic yield function proposed by one of investigators. Evaluating the void distribution by the stereological method together with the use of Dirichlet tessellation, the effect of void spacing during plastic deformation can be treated quantitatively. This means that the procedure proposed here may become a useful tool for evaluating the overall plastic property of the material with microstructures, though a further examination will be necessary for precise description of the resulting anisotropic behavior of perforated sheets.
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