| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To measure a damage length with high reliability and high accuracy, by correcting incorrect detection of a peak of vibration wave. <P>SOLUTION: The vibrations, which are oscillated by a vibrator 3 and which are propagated through an object to be measured including members 1 and 2, are detected by three sensors 4, 5 and 6, respectively. A measurement apparatus 7 analyzes that vibration wave, and measures the arrival time of the maximum peak. The arrival time of the maximum peak about a previously measured object to be measured having no damage is recorded, and the damage length is calculated based on the difference (delay time of the maximum peak) from this. Using the fact that the time for a wave to propagate between two vibration detection sensors separated by a set interval is fixed, the measurement apparatus 7 determines whether the difference in arrival time between two sensors is within a set reference range that includes the vibration propagation time between two vibration sensors. When the measurement apparatus 7 determines that the difference is not within the set reference range, it uses the fact that incorrect wave is delayed compared with the wave to be detected, detects a peak of a predetermined amplitude or higher that reaches ahead of maximum peak, and calculates the damage length by replacing the incorrect peak by the detected peak. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
