| 摘要 |
PROBLEM TO BE SOLVED: To enable the evaluation of not only flaws but flaw sizes by transmitting ultrasonic waves into an object whose flaws are to be detected, receiving returned ultrasonic waves, determining its reception sound pressure, and determining flaw sizes on the basis of the sound pressure. SOLUTION: A terminal microcomputer 100 sends an actuating signal to a high frequency transmitter 32 via a driver 31 and sends a generated actuating signal to the spiral coil 4 of a PPM electromagnetic ultrasonic transducer 2 via an amplifier 33 and diplexer 34. By this, SH waves are excited to a tubular body, and the SH waves returned from a predetermined propagation path are detected by the spiral coil 4. The detected signal is sent to the terminal microcomputer 100 via an amplifier 35, a BPF 36, and an A/D converter 37. The flaw evaluating part 7 of the terminal microcomputer 100 determines the amplitude of the detected signal i.e., the sound pressure level of the SH waves inputted from the A/D converter 37. In reference to a lookup table indicating the relation between sound levels and flaw sizes with this sound pressure level, it is possible to determine the depth of flaws. |
