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Novatest S.r.l.
Manual for Multichannel Ultrasonic Pile Integrity Tester
25
or crack may destroy the integrity of concrete, sound wave has to
bypass cavitations or crack and transmit to receiving transducer; the
longer the transmission distance is, the longer the tested acoustic time
is, and acoustic speed decreases correspondingly. Reflection,
scattering and energy attenuation caused by ultrasonic on defect
interface may result in decrease of amplitude; the attenuation degrees
are different when various frequencies in sound wave encountering
defect; high frequency has large attenuation, which makes basic
frequency decreases (frequency shift). Besides, waveform conversion
and addition of sound wave at defect make waveform distortion.