| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a system for measuring the wall thickness of a metal pipe by a hammering sound simply and highly accurately. SOLUTION: This system includes a hammering sound data acquisition part 1 for collecting and preserving a sound pressure signal sample value by applying hammering having prescribed strength to the metal pipe, and a data analysis part 2 for determining the wall thickness by analyzing the preserved sound pressure signal sample value. The data analysis part includes means 23, 21 for displaying a wall thickness-characteristic frequency straight line showing the relation between the characteristic frequency and the wall thickness determined, based on each hammering test of a plurality of sample metal pipes having different wall thicknesses having the same diameter as the metal pipe which is a measuring object, an autocorrelation processing means 24 for determining time-series data by applying autocorrelation processing to the preserved sound pressure signal sample value, and a frequency component analysis means 25 for performing graph display of the frequency component by applying FFT (Fast Fourier Transform) to the time-series data. When measuring the wall thickness, the characteristic frequency of the metal pipe is acquired from the graph display of the frequency component, and the wall thickness of the metal pipe is determined by using the acquired characteristic frequency and the graph display of the wall thickness-characteristic frequency straight line. COPYRIGHT: (C)2007,JPO&INPIT
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