Abstract
Acoustic imaging techniques are used in the field of nondestructive testing of technical components to measure defects such as lack of side wall fusion or cracks in welded joints. Data acquisition is performed by a remote-controlled manipulator and a PC for the mass storage of the high-frequency time-of-flight data at each probe position. The quality of the acoustic images and the interpretation relies on the proper understanding of the transmitted wave fronts and the arrangement of the probes in pulse—echo mode or in pitch-and-catch arrangement. The use of the Synthetic Aperture Focusing Technique allows the depth dependent resolution to be replaced by a depth-independent resolution and the signal-to-noise ratio to be improved. Examples with surface-connected cracks are shown to demonstrate the improved features. The localization accuracy could be improved by entering 2-dimensional or 3-dimensional reconstructed data into the environment of a 3-dimensional CAD drawing. The propagation of ultrasonic waves through austenitic welds is disturbed by the anisotropic and inhomogeneous structure of the material. The effect is more or less severe depending upon the longitudinal or shear wave modes. To optimize the performance of an inspection software tool, a 3-dimensional CAD-Ray program has been implemented, where the shape of the inhomogeneous part of a weld can be simulated together with the grain structure based on the elastic constants. Ray-tracing results are depicted for embedded and for surface-connected defects.
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References
R. Marklein, Numerische Verfahren zur Modellierung von akustischen, elektromagnetischen, elastischen und piezoelektrischen Wellenausbreitungsproblemen im Zeitbereich basierend auf der Finiten Integrationstechnik (Shaker, Aachen 1997)
D. W. Prine, Synthetic Aperture Ultrasonic Imaging, In Proc. Engineering Applications of Holography Symp. (Society of Photo-optical Instrumentation Engineers, Los Angeles, 1972) p. 287
C. B. Burckhardt, P. A. Grandchamp, H. Hoffmann, Methods for Increasing the Lateral Resolution of B-Scan, In Acoustical Imaging, Vol. 5, ed. by P.S. Green (Plenum, New York 1974)
J. R. Frederick, J. A. Seydel, R. C. Fairchild. Improved Ultrasonic Non-Destructive Testing of Pressure Vessels, NUREG-0007-2 (University of Michigan, Ann Arbor 1976)
J. L. Jackson, Program for Field Validation of the Synthetic Aperture Focusing Technique for Ultrasonic Testing (SAFT-UT)-Analysis Before Test, NUREG/CR-0288 (Southwest Research Institute, San Antonio 1978) 171
S. R. Doctor, G. J. Schuster, L. D. Reid, T. E. Hall, Real-Time 3-D SAFT-UT System Evaluation and Validation, NUREG/CR-6344 PNNL-10571 (Pacific Northwest National Laboratory, Richland 1996)
V. Schmitz, Line Synthetic Aperture Focusing Technique, IZFP Report 001 (IZFP, Saarbrücken 1981)
V. Schmitz, W. Müller, K. J. Langenberg, HOLOSAFT II, Final Report 920206 (FHGIZFP, Saarbrücken 1992)
K. J. Langenberg, M. Brandfaß, R. Hannemann, C. Hofmann, T. Kaczorowski, J. Kostka, R. Markelein, K. Mayer, A. Pitsch, Inverse scattering with acoustic, electromagnetic and elastic waves as applied in nondestructive evaluation, In Wavefield Inversion, ed. by A. Wirgin (Springer, Vienna 1999)
K. J. Langenberg: Applied inverse problems, In Basic Methods of Tomography and Inverse Problems, ed. by P.C. Sabatier (Adam Hilger, Bristol 1987)
K. Mayer, R. Marklein, K. J. Langenberg, T. Kreutter, Three-dimensional imaging system based on fourier transform synthetic aperture focussing technique, Ultrasonics 28, 241 (1990)
L. J. Cutrona, Comparison of sonar system performance achievable using synthetic aperture focusing techniques with the performance available by more conventional means, J. Acoust. Soc. Am. 58, 336–348 (1975)
J. A. Ogilvy, Computerised ultrasonic ray tracing in austenitic steels, Nonde-struct. Test. Int. 18, 67–77 (1985)
V. Schmitz, F. Walte, S. V. Chakhlov, 3D Ray Tracing in Austenite Materials, Nondestruct. Test. Eng. Int. 32, 201–213 (1999)
V. Schmitz, F. Walte, S. V. Chakhlov, Modeling of sound fields through austenitic welds, In Proc. First Int. Conf. NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, Amsterdam (1998)
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Schmitz, V. (2002). Nondestructive Acoustic Imaging Techniques. In: Fink, M., Kuperman, W.A., Montagner, JP., Tourin, A. (eds) Imaging of Complex Media with Acoustic and Seismic Waves. Topics in Applied Physics, vol 84. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-44680-X_7
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DOI: https://doi.org/10.1007/3-540-44680-X_7
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