Abstract
This work is devoted to modelling the diffraction of a focused ultrasonic beam by a fatigue crack-life flaw. Beforehand, a bibliographical study surveys the methods available to deal with this problem. An integrated two-dimensional monochromatic model is then developed. The focused ultrasonic beam after a fluid/solid interface is modelled on the basis of the RAYLEIGH-SOMMERFELD formalism. The interaction of the beam and the crack edges is treated via the Geometrical Theory of Diffraction. The crack response is calibrated using a KIRCHOFF computation on a reference reflector (Side-Drilled-Hole). An experimental study, carried out on an embedded crack, validates the echographic response amplitudes predicted by the model within 3dB. The monochromatic model is then extended to a broad-band model by means of a FOURIER analysis. This makes it possible to predict the complete waveforms. An experimental verification shows that the model simulates correctly the respectives shapes and polarities of the pulses diffracted by plane or volumetric defects, as well as the result of interferences between several pulses. Eventually, the particular case of a defect located near the outer wall of the rested material is dealt with. The `corner effect` echographic response is modelled via via the KIRCHOFF theory. The quantitative agreement with
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Citation Formats
Laval, M.
Diffraction study of a focused ultrasonic beam by a defect. Prediction of the echographic response of a given defect; Etude de la diffraction subie par le champ ultrasonore d`un traducteur focalise en presence d`un defaut. Prediction de la reponse echographique d`un defaut donne.
France: N. p.,
1992.
Web.
Laval, M.
Diffraction study of a focused ultrasonic beam by a defect. Prediction of the echographic response of a given defect; Etude de la diffraction subie par le champ ultrasonore d`un traducteur focalise en presence d`un defaut. Prediction de la reponse echographique d`un defaut donne.
France.
Laval, M.
1992.
"Diffraction study of a focused ultrasonic beam by a defect. Prediction of the echographic response of a given defect; Etude de la diffraction subie par le champ ultrasonore d`un traducteur focalise en presence d`un defaut. Prediction de la reponse echographique d`un defaut donne."
France.
@misc{etde_10129875,
title = {Diffraction study of a focused ultrasonic beam by a defect. Prediction of the echographic response of a given defect; Etude de la diffraction subie par le champ ultrasonore d`un traducteur focalise en presence d`un defaut. Prediction de la reponse echographique d`un defaut donne}
author = {Laval, M}
abstractNote = {This work is devoted to modelling the diffraction of a focused ultrasonic beam by a fatigue crack-life flaw. Beforehand, a bibliographical study surveys the methods available to deal with this problem. An integrated two-dimensional monochromatic model is then developed. The focused ultrasonic beam after a fluid/solid interface is modelled on the basis of the RAYLEIGH-SOMMERFELD formalism. The interaction of the beam and the crack edges is treated via the Geometrical Theory of Diffraction. The crack response is calibrated using a KIRCHOFF computation on a reference reflector (Side-Drilled-Hole). An experimental study, carried out on an embedded crack, validates the echographic response amplitudes predicted by the model within 3dB. The monochromatic model is then extended to a broad-band model by means of a FOURIER analysis. This makes it possible to predict the complete waveforms. An experimental verification shows that the model simulates correctly the respectives shapes and polarities of the pulses diffracted by plane or volumetric defects, as well as the result of interferences between several pulses. Eventually, the particular case of a defect located near the outer wall of the rested material is dealt with. The `corner effect` echographic response is modelled via via the KIRCHOFF theory. The quantitative agreement with experimental data is very good. Further experimentation will be needed to assess the quantitative reliability of the model.}
place = {France}
year = {1992}
month = {Feb}
}
title = {Diffraction study of a focused ultrasonic beam by a defect. Prediction of the echographic response of a given defect; Etude de la diffraction subie par le champ ultrasonore d`un traducteur focalise en presence d`un defaut. Prediction de la reponse echographique d`un defaut donne}
author = {Laval, M}
abstractNote = {This work is devoted to modelling the diffraction of a focused ultrasonic beam by a fatigue crack-life flaw. Beforehand, a bibliographical study surveys the methods available to deal with this problem. An integrated two-dimensional monochromatic model is then developed. The focused ultrasonic beam after a fluid/solid interface is modelled on the basis of the RAYLEIGH-SOMMERFELD formalism. The interaction of the beam and the crack edges is treated via the Geometrical Theory of Diffraction. The crack response is calibrated using a KIRCHOFF computation on a reference reflector (Side-Drilled-Hole). An experimental study, carried out on an embedded crack, validates the echographic response amplitudes predicted by the model within 3dB. The monochromatic model is then extended to a broad-band model by means of a FOURIER analysis. This makes it possible to predict the complete waveforms. An experimental verification shows that the model simulates correctly the respectives shapes and polarities of the pulses diffracted by plane or volumetric defects, as well as the result of interferences between several pulses. Eventually, the particular case of a defect located near the outer wall of the rested material is dealt with. The `corner effect` echographic response is modelled via via the KIRCHOFF theory. The quantitative agreement with experimental data is very good. Further experimentation will be needed to assess the quantitative reliability of the model.}
place = {France}
year = {1992}
month = {Feb}
}