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DOI:

2014. . No. 4(66) - Dec 2014, pp. 61-64

AE Analysis of Characteristic Ultrasonic Harmonics in Thick-Walled Metal Objects at Impacts

T. B. Petersen

The phenomenon of stress waves radiation excited at solids collision is used in various applications connected with non-destructive testing. When using the AE technique for registration of acoustic sources, in particular impacts, location and identification of the impact source are usually determined and additionally duration, speed, and risk of the impact are estimated. The article demonstrates advanced capabilities of AE method to retrieve from the digitized signals not only information about the actual impacts, but also parameters and properties of the test object, directly during operation. The calculation method is based on the harmonic analysis of AE signals registered at impacts of solid objects on the surface of the thick-walled object. A diagram explaining the formation of basic frequencies for normal and oblique impacts as well as corresponding harmonics contained in the spectra of the signals is presented. Numerical evaluation of test object material mechanical and acoustic properties obtained by the proposed AE data processing method is given.
 
Keywords: impact, Lamb waves, acoustic emission, harmonic analysis
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