| 摘要 |
PURPOSE:To inspect a bonded part by making acoustic waves to be made incident on one of bonded two materials from the surface and, at the same time, detecting the reflecting waves of the acoustic waves, and then, preparing frequency spectra by Fourier-transforming the detected reflecting wave signals and discriminating the pattern. CONSTITUTION:A plastic delay 5 for providing intervals between each reflecting wave component is joined to the surface of a steel plate 1 and the acoustic waves of 10MHz are made incident on the plastic delay 5 from the steel plate 1 side. For this purpose, acoustic waves A(t) are made incident by using an ultrasonic flaw detector 6 and wide-band probe 7 and, at the same time, multiple reflecting waves from internal interfaces are received and monitored by means of an oscilloscope 8. Moreover, the multiple reflecting waves are electrically fetched and inputted in a spectrum analyzer 9. Then the reflecting waves are subjected to Fourier transformation process in such a way that only the 1st reflecting wave I1(t) from the joined interface is first fetched and Fourier-transformed. The Fourier-transformed reflecting wave is displayed on a screen in dB display and, simultaneously, stored in the analyzer 9 as a memory A. Then a totally reflecting wave R(t) is Fourier-transformed and used as a memory B and the joined condition is discriminated by finding (B-A).
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