| Project/Area Number |
03650058
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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 |
機械材料工学
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| Research Institution | Ibaraki University |
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Principal Investigator |
OKAMOTO Yoshizo Ibaraki Univ. Div. of Engng. Prof., 工学部, 教授 (10194408)
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| Co-Investigator(Kenkyū-buntansha) |
神永 文人 茨城大学, 工学部, 助教授 (80114015)
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| Project Period (FY) |
1991 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1993: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1992: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1991: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | Flaw / Detection Limit / Nondestructive Test / Infrared Way / Thermal Image Method / Normal Heating Method / Lateral Heating Method / Radiation Temperature Image / 温度分布 / 高熱流束加熱試験 / 赤外線映像装置 / 可視化計測 / 表面加熱 / 熱的非破壊検査基準 / リモートセンシング / モルタル / 金属 / 拡大流れ / 太陽 / 入射熱流束 / 放射率 / 可変微動装置 / 人工内部欠陥 / ワイヤ-カット / 線状欠陥 / 均一性 |
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| Research Abstract |
A new thermal radiation technique using an infrared radiometer had been developed to detect internal flaws of materials used, such as inclusion, crack, gap and pinhole. In this study, several incident thermal energies like sun, lamp and hot gas, were injected to the test material with artifical internal flaws. Transient radiation temperature of the surface above the internal flaws were displayd on the CRT by means of the infrared radiometer. The radiation temperature difference between the surface and flaws represents the existance of the internal flaws. Characteristics of various heat injection methods, such as normal and lateral heatings were compared with each others by using test pieces of metal, ceramic, plastic and insulator.
Stepwise high-flux heat injection test had been undertaken, using a Halogen lamp with a parabolic stainless mirror coated by gold in case of the normal heating. And the injected heat from lateral side of the test piece flows to the other side of the piece by heat conduction in case of the lateral heating. We visualized the mountainous and valley-like temperature distribution above the internal flaws at the normal heating and discontinuous temperature difference above the flaws at the lateral heating. Test results show that the lateral heating method is more superior than the normal heating in case of detecting the slit flaw and inferior than the normal heating in case of detecting the pin-hole flaw.
The detection limit of internal flaws is determined by the surface tempeature variance of the tested material. The transient heat flow arround the internal flaws were numerically analyzed by solving a 2-dimensional heat conduction equation to verify the surface temperature distribution above the flaws.
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