| 摘要 |
PURPOSE:To prevent the damage of a structure, in a machine structure receiving fatigue and creep damage by repeated or varied load at high temp., by calculating the life of a member on the basis of the change quantity of the microscopic surface damage of the member. CONSTITUTION:A potential difference measuring part is constituted of a constant current generator and a potential difference detection voltmeter 17. A damage sensor 14 has a minute crack preliminarily provided to the central part thereof and the terminal connected to the voltmeter measuring the change in potential difference is adhered in the vicinity of said initial minute crack. Hereupon, because a potential difference ratio corresponds to the length of the crack, if the relation therebetween is preliminarily calculated, it is easy to calculate the length of the crack from the potential difference ratio. When strain is repeatedly loaded to both terminals of the damage sensor 14, the crack at the central part is grown and, as a result, the relation between the number of repetitions and the potential difference ratio is calculated. Then, the unique relation is also calculated between the potential difference ratio and a life consumption ratio. Therefore, by measuring the potential difference ratio of the damage sensor, the life consumption ratio is calculated.
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