| 摘要 |
PROBLEM TO BE SOLVED: To perform surface flaw detection by scanning a rotor circumferentially without stopping the rotation of the rotor. SOLUTION: An inspection target 1 rotated at a definite speed is irradiated with an exciting pulse laser beam at definite frequency to repeatedly generate the ultrasonic waves propagating along the surface the inspection target 1, the surface displacement due to the ultrasonic waves is measured at a position 8 separate from the irradiation position 7 of the exciting pulse laser beam using a laser interferometer synchronized with the exciting pulse laser beam to detect a surface flaw 6 on the way of an ultrasonic propagation route 5 on the basis of a change in a measuring waveform. The irradiation position 7 of the exciting pulse laser beam to the inspection target 1 and the irradiation position 8 of the measuring laser beam of the laser interferometer are fixed and, by differentiating the rotary cycle Tr of the inspection target 1 and the irradiation cycle Ts of the exciting pulse laser beam, the region 10 excited by the exciting pulse laser beam of the inspection target 1 and the region 11 measured by the laser interferrometer are gradually shifted circumferentially in the inspection target 1 to perform scanning. COPYRIGHT: (C)2011,JPO&INPIT
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