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A comparison of the experimentally measured and the simulated waveforms of a guided-wave signal re ected from a notch in a pipe is presented. The simulated waveforms were calculated analytically by using a recently proposed transmission-line model and its modi ed version that accounted for the wave di raction at the backend of the notch. Results are shown for longitudinal guided-wave signals re ected from notches of constant circumferential cross-section with the width along the lengthwise direction of the pipe ranging from 6.35 to 101.6 mm. The results of the simulation made with the modi ed model agree very well with the experimentally measured waveforms and qualitative changes in the re ection coecients with the notch width. Quantitatively, the calculated re ection coecients were consistently smaller than the experimental values, in general by about 50 %. The good agreement between the experimentally measured and the simulated waveforms indicates that, for a defect with an abruptly changing cross-section, wave di raction plays an important role in determining the defect signal waveform.


A comparison of the experimentally measured and the simulated waveforms of a guided-wave signal re ected from a notch in a pipe is presented. The simulated waveforms were calculated analytically by using a recently proposed transmission-line model and its modi ed version that accounted for the wave di raction at the backend of the notch. Results are shown for longitudinal guided-wave signals re ected from notches of constant circumferential cross-section with the width along the lengthwise direction of the pipe ranging from 6.35 to 101.6 mm. The results of the simulation made with the modi ed model agree very well with the experimentally measured waveforms and qualitative changes in the re ection coecients with the notch width. Quantitatively, the calculated re ection coecients were consistently smaller than the experimental values, in general by about 50 %. The good agreement between the experimentally measured and the simulated waveforms indicates that, for a defect with an abruptly changing cross-section, wave di raction plays an important role in determining the defect signal waveform.