Article Article
New Approaches for Testing of Adhesive Joints by Ultrasonic C-scan Imaging Technique

Various destructive and nondestructive testing techniques have been used for testing the joint quality in adhesive bonding. Ultrasonic testing has proven to be one the most efficient methods for this purpose. Among the many different ultrasonic testing techniques, C-scan imaging seems to be the most efficient for testing adhesive joints. In this paper, new testing schemes are proposed for extraction of the required information from the ultrasonic signals acquired in a C-scan imaging process. Three different indices, which are based on the amplitudes of the ultrasonic radio frequency signals, are introduced. Compared to the gating and peak detection approach used in conventional ultrasonic C-scan imaging, these indices provide much more information about the quality of the bonding in an adhesive joint. Moreover, while only one side of the adhesive layer can be tested in conventional C-scan imaging, the new technique makes the testing of both sides of the adhesive possible with scanning performed on one side of the specimen. Furthermore, in the case of very thin samples, where the returned echoes are not separable and, hence, no C-scan images can be generated, the new technique works quite well. The capability of the proposed approach in providing C-scan images from a number of samples, some of which are considered not to be testable by conventional ultrasonic testing techniques, is demonstrated.

Allin, J.M., P. Cawely and M.J.S. Lowe, “Adhesive Disbond Detection of Automotive Components Using First Mode Ultrasonic Resonance,” NDT&E International, Vol. 36, 2003, pp. 503–514. Barnes, T.A. and I.R. Pashby, “Joining Techniques for Aluminum Spaceframes Used in Automobiles: Part II — Adhesive Bonding and Mechanical Fasteners,” Material Process Technology, Vol. 99, 2000, pp. 72–79. Challis, R., R. Freemantle, G. Wilkinson and J. White, “Compression Wave NDE of Adhered Metal Lap Joints: Uncertainties and Echo Feature Extraction,” Ultrasonics, Vol. 34, 1996a, pp. 315–319. Challis, R., U. Bork and P. Todd, “Ultrasonic NDE of Adhered Joints Using Lamb Wave and Intelligent Signal Processing,” Ultrasonics, Vol. 34, 1996b, pp. 455–464. Chapman, G., J. Sadler, R. Maev, S. Titov, E. Maeva, I. Severina and F. Severin, “Ultrasonic Pulse-Echo NDE of Adhesive Bonds in Sheet-Metal Assemblies,” IEEE International Ultrasonics Symposium, 2006, pp. 902–905. Dalton, R., The Propagation of Lamb Waves through Metallic Aircraft Fuselage Structure, Ph.D. dissertation, Imperial College, London, 2000. Goglio, L. and M. Rossetto, “Ultrasonic Testing of Adhesive Bond of Thin Metal Sheets,” NDT&E International, Vol. 32, 1999, pp. 323–331. Heller, K., L. Jacobs and J. Qu, “Characterization of Adhesive Bond Properties Using Lamb Waves,” NDT&E International, Vol. 33, 2000, pp. 555– 563. Krautkramer, J. and H. Krautkramer, Ultrasonic Testing of Materials, fourth edition, Berlin, Springer-Verlag, 1990. Lowe, M., R. Challis and C. Chan, “The Transmission of Lamb Waves Across Adhesively Bonded Lap Joints,” Journal of the Acoustical Society of America, Vol. 107, 2000, pp. 1333–1378. Maev, R. and S. Titov, “Pulse-Echo Ultrasonic NDE of Adhesive Bonds in Automotive Assemblies,” European Conference on NDT (ECNDT),, Vol. 11, 2006, /ecndt2006/papers~1.htm. Maeva, E., I. Severina, A. Bugaev, F. Severin and R. Maev, “Acoustical Imaging Evaluation of Thin Metal–Metal Adhesive Bonds,” IEEE International Ultrasonics Symposium, 2003, pp. 2037–2040. Maeva, E., I. Severina, S. Bondarenko, G. Hapman, B. O’Neil, F. Severin and R. Maev, “Acoustical Methods for the Investigation of Adhesively Bonded Structures: A Review,” Canadian Journal of Physics, Vol. 82, 2004, pp. 981–1025. Munns, I.J. and G.A. Georgiou, “Nondestructive Testing Methods for Adhesively Bonded Joints Inspection — A Review,” Insight, Vol. 37, 1995, pp. 941–952. Tavrou, C.K., Evaluation of Adhesively Bonded Steel Sheet Using Ultrasonic Techniques, Ph.D. dissertation, Swinburne University of Technology, Melbourne, Australia, 2005. Titov, S., R. Maev and A. Bogachenkov, “Pulse-Echo NDT of Adhesively Bonded Joints in Automotive Assemblies,” Ultrasonics, Vol. 48, 2008, pp. 537–546. Vine, K., P. Cawley and A. Kinloch, “Comparison of Normal and Oblique Incidence Ultrasonic Measurements for the Detection of Environmental Degradation of Adhesive Joints,” NDT&E International, Vol. 35, 2002, pp. 241–253.
Usage Shares
Total Views
115 Page Views
Total Shares
0 Tweets
0 PDF Downloads
0 Facebook Shares
Total Usage