2005 Fiscal Year Final Research Report Summary
Study on the Thermal Shock Fracture Mechanism of Ceramics Based on the Dynamic Characterization of Thermal Stress and Microfracture Process
| Project/Area Number |
15360349
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | TOKYO METROPOLITAN UNIVERSITY |
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Principal Investigator |
WAKAYAMA Shuichi Tokyo Metropolitan University, Department of Mechanical Engineering, Associate Professor, 都市教養学部理工学系, 助教授 (00191726)
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| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI Satoshi Tokyo Metropolitan University, Department of Mechanical Engineering, Associate Professor, 都市教養学部理工学系, 助教授 (80326016)
AKATSU Takashi Tokyo Institute of Technology, Materials and Structures Laboratory, Assistant Professor, 応用セラミックス研究所, 講師 (40231807)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Ceramics / Thermal Schock Fracture / AE Analysis / FEM / Microfracture Process / Long-Term Reliability |
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| Research Abstract |
Ceramic materials used at elevated temperatures are usually subjected to damage due to thermal shock fracture. One of the most popular thermal shock tests is the water quench test, in which the critical temperature difference, where samples are subjected to severe damage, is used as a measure of the thermal shock resistance. However the characterization of microfracture process under thermal shock as well as transient thermal stress field is indispensable, since thermal shock fracture is caused by the accumulation of microscopic damages such as microcrackings under thermal stress. In this project, a new experimental technique for the investigation of thermal shock fracture behavior, Disc-on-Rod test, is proposed. The temperature fields in the specimen were measured and used to calculate the 2 dimensional thermal stress field. Furthermore, microfracture process was characterized by AE measurement. In the present project, followings have been achieved.
1. Experimental system of Disc-on-Rod test was significantly developed. The in-situ observation of crack initiation and propagation behavior under thermal shock was enabled by digital video camera unit. Furthermore, the 3D-analysis of thermal stress was enabled by introducing full-version FEM code (ANSYS).
2. The crack propagation behavior under thermal shock was characterized dynamically. The dependence of crack stability on the length of pre-crack was understood quantitatively, which showed good agreement of theoretical prediction by Hasselman's unified theory. In addition, the crack growth behavior of toughened ceramic composites was characterized successfully.
3. Non-destructive evaluation technique of microfracture process in ceramics under mechanical loading was drastically developed and applied to bioceramics. The assessment technique of long-term reliability of ceramics was developed and will be applied to thermal shock fracture.
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Research Products
(17 results)
