1998 Fiscal Year Final Research Report Summary
Damage theory of discontinuously-reinforced composites with reinforcement cracking and mechanism to produce high performance
| Project/Area Number |
09650095
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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 | Shizuoka University |
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Principal Investigator |
TOHGO Keiichiro Shizuoka University, Faculty of Engineering, Professor, 工学部, 教授 (10155492)
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| Co-Investigator(Kenkyū-buntansha) |
ARAKI Hiroyasu Shizuoka University, Faculty of Engineering, Research Associate, 工学部, 助手 (60115433)
ISHII Hitoshi Shizuoka University, Faculty of Engineering, Professor, 工学部, 教授 (90022235)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Discontinuously-reinforced composite / Damage theory / Micromechanics / Shape memory alloy composite / Reinforcement cracking / Debonding damage |
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| Research Abstract |
In the particle or short-fiber reinforced composites, cracking damage of reinforcements and debonding damage of reinforcement-matrix interface develop from early stage of deformation, and affect the mechanical performance of the composites. In this project, an incremental damage theory of the composites has been developed, and an influence of damage on the mechanical performance of the discontinuously-reinforced composites has been discussed based on the numerical and experimental results. Obtained results are summarized as follows.
1. A damage theory of the discontinuously-reinforced composites, which can describe the progressive debonding or cracking damage of reinforcements and the matrix plasticity, was established based on the micromechanics approach. Furthermore, a finite element method was developed by introducing the damage theory.
2. The damage process and the influence of damage on the mechanical performance were examined on glass-particle-reinforced nylon 66 composites in which the particle content and interfacial strength were changed. The debonding damage reduces the tensile strength and fatigue strength, and enhances the fracture toughness and fatigue crack growth resistance.
3. Tensile stress-strain relation and crack-tip field of glass-particle-reinforced nylon 66 composites were analyzed based on the damage theory. It was found from the experimental and numerical results that the mechanical performance of the composites are obtained as the results of the competitive effects of the intact hard particles and the debonding damage.
4. In order to investigate the potentiality of the shape memory alloy composites, a constitutive relation of the composites under thermo-mechanical loading were developed and the deformation and strength of TiNi-poly carbonate composites were tested.
From the above results, many suggestions to produce the composite with high-performance were obtained.
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