1994 Fiscal Year Final Research Report Summary
Research on the method of dynamic strength evaluation of ceramics by caustics
Project/Area Number |
05650095
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Research Category |
Grant-in-Aid for General Scientific Research (C)
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Allocation Type | Single-year Grants |
Research Field |
Materials/Mechanics of materials
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Research Institution | Kanto Gakuin University |
Principal Investigator |
SHIMIZU Koji Kanto Galuin University, Faculty of Engineering, Professor, 工学部, 教授 (00005373)
|
Project Period (FY) |
1993 – 1994
|
Keywords | Caustic Method / High Temperature Fracture / Dynamic Fracture / Fracture Toughness / Ceramics / Mode II / AE-Wave / Image Processing |
Research Abstract |
Dynamic fracture behavior of the ceramics at various temperatures is investigated by using the caustic method together with ultra high-speed camera, heating furnace and dynamic loading device, and moreover, some improvements of the technique of caustics are studied. Consequently, the following results are obtained. (1) Clear caustic pattern can be obtained by preparing the specimen with highly polished surface and by using the specially arranged optical setup. It is shown that the caustic method can be applied for studying the fracture of ceramics under dynamic loading at high temperature. (2) For zirconium ceramics, it is possible to perform experiment up to the temperature of 1200゚C by using 2mW gas laser light source and for silicon-nitride ceramics, it is possible to obtain a clear caustic pattern up to 1100゚C by using 35mW laser. It is revealed that effects of temperature and loading rate on the fracture behavior are considerably large in zirconium ceramics, but those effects are not so large in silicon-nitride ceramics. (3) A clear caustic pattern can be obtained for aluminum and sialon ceramics by employing multiplication technique of caustics. (4) It is shown that the effect of the size of initial curve on K-value is very small under Mode II loading condition. (5) The visualized pattern based on AE-wave is also obtained and it is shown that this pattern propagated at Rayleigh wave velocity. (6) By introducing the image processing technique, it is possible to improve the accuracy of caustics. Moreover, a simple technique for measuring the elastic constants is proposed. Through this study, some improvements of experimental technique are accomplished and a basic technique for evaluating strength of ceramics under dynamic loading at high temperature is proposed.
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Research Products
(10 results)