Nondestructive Acoustic Imaging Techniques

  • Volker Schmitz
Part of the Topics in Applied Physics book series (TAP, volume 84)


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.


Longitudinal Wave Grain Orientation Ultrasonic Inspection Slag Inclusion Weld Structure 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    R. Marklein, Numerische Verfahren zur Modellierung von akustischen, elektromagnetischen, elastischen und piezoelektrischen Wellenausbreitungsproblemen im Zeitbereich basierend auf der Finiten Integrationstechnik (Shaker, Aachen 1997)Google Scholar
  2. 2.
    D. W. Prine, Synthetic Aperture Ultrasonic Imaging, In Proc. Engineering Applications of Holography Symp. (Society of Photo-optical Instrumentation Engineers, Los Angeles, 1972) p. 287Google Scholar
  3. 3.
    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)Google Scholar
  4. 4.
    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)Google Scholar
  5. 5.
    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) 171Google Scholar
  6. 6.
    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)Google Scholar
  7. 7.
    V. Schmitz, Line Synthetic Aperture Focusing Technique, IZFP Report 001 (IZFP, Saarbrücken 1981)Google Scholar
  8. 8.
    V. Schmitz, W. Müller, K. J. Langenberg, HOLOSAFT II, Final Report 920206 (FHGIZFP, Saarbrücken 1992)Google Scholar
  9. 9.
    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)Google Scholar
  10. 10.
    K. J. Langenberg: Applied inverse problems, In Basic Methods of Tomography and Inverse Problems, ed. by P.C. Sabatier (Adam Hilger, Bristol 1987)Google Scholar
  11. 11.
    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)CrossRefGoogle Scholar
  12. 12.
    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)CrossRefADSGoogle Scholar
  13. 13.
    J. A. Ogilvy, Computerised ultrasonic ray tracing in austenitic steels, Nonde-struct. Test. Int. 18, 67–77 (1985)Google Scholar
  14. 14.
    V. Schmitz, F. Walte, S. V. Chakhlov, 3D Ray Tracing in Austenite Materials, Nondestruct. Test. Eng. Int. 32, 201–213 (1999)Google Scholar
  15. 15.
    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)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2002

Authors and Affiliations

  • Volker Schmitz
    • 1
  1. 1.Fraunhofer Institute for Nondestructive TestingUniversität SaarbrückenSaarbrückenGermany

Personalised recommendations