A technique for the application of composite patches for repairing metallic structures has been developed recently. In order to achieve to an effective repair, high-quality patches and bonding should be used. Various ultrasonic testing (UT) techniques, such as pulse-echo, are commonly used to check the patch and bonding. Ultrasonic measurements are associated with some limitations, especially for the multilayered structures, due to the presence of a significant amount of noise in the scan images. In order to enhance the UT images, various processing techniques can be employed. In the present research, different image processing algorithms based on morphology techniques have been adopted to enhance the C-scan images obtained from the ultrasonic measurement of five carbon/epoxy patches bonded to an aluminum plate. Twelve delaminations with various sizes and locations along with three disbond discontinuities were artificially embedded in the five patches. The processed and input images have been quantitatively compared to clarify how useful the utilized morphology processing algorithms can be. According to the comparison results, a morphology-based processing algorithm that is more useful than the others has been introduced.
Abbate, A., J. Koay, J. Frankel, S. C. Schroeder, and P. Das, 1997, “Signal Detection and Noise Suppression Using a Wavelet Transform Signal Processor: Application to Ultrasonic Flaw Detection,” IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, Vol. 44, No. 1, pp. 14–26.
Aptoula, E., and S. Lefèvre, 2007, “A Comparative Study on Multivariate Mathematical Morphology,” Pattern Recognition, Vol. 40, pp. 2914–2929.
Aymerich, F., and S. Meili, 2000, “Ultrasonic Evaluation of Matrix Damage in Impacted Composite Laminates,” Composites Part B: Engineering, Vol. 31, No. 1, pp. 1–6.
Bobin, J., J.L. Starck, J. M. Fadili, Y. Moudden, and D. L. Donoho, 2007, “Morphological Component Analysis: An Adaptive Thresholding Strategy,” IEEE Transactions on Image Processing, Vol. 16, No. 11, pp. 2675–2681.
Chang, J., C. Zheng, and Q. Ni, 2006, “The Ultrasonic Wave Propagation in Composite Material and Its Characteristic Evaluation,” Composite Structures, Vol. 75, No. 1–4, pp. 451–456.
Codaro, E.N., R.Z. Nakazato, A.L. Horovistiz, L.M.F. Ribeiro, R.B. Ribeiro, and L.R.O. Hein, 2002, “An Image Processing Method for Morphology Characterization and Pitting Corrosion Evaluation,” Materials Science Engineering: A, Vol. 334, No. 1–2, pp. 298–306.
Djordjevic, B.B., 2014, “Ultrasonic Nondestructive Testing of Large-Scale Composites,” Materials Evaluation, Vol. 72, No. 7, pp. 922–927.
Frock, B.G., and R.W. Martin, 1989, “Digital Image Enhancement for Ultrasonic Imaging of Defects in Composite Materials,” Materials Evaluation, Vol. 47, No. 4, pp. 442–447.
Katnam, K.B., L.F.M. Da Silva, and T.M. Young, 2013, “Bonded Repair of Composite Aircraft Structures: A Review of Scientific Challenges and Opportunities,” Progress in Aerospace Sciences, Vol. 61, No. 8, pp. 26–42.
Haralick, R.M., S. R. Sternberg, and X. Zhuang, 1987, “Image Analysis Using Mathematical Morphology,” IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. 9, No. 4, pp. 532–550.
Imielińska, K., M. Castaings, R. Wojtyra, J. Haras, Le Clezio, and B. Hosten, 2004, “Air-Coupled Ultrasonic C-Scan Technique in Impact Response Testing of Carbon Fibre and Hybrid: Glass, Carbon and Kevlar/Epoxy Composites,” Journal of Materials Processing Technologies, Vol. 157–158, pp. 513–522.
Liu, L., B.M. Zhang, D.F. Wang, and Z.J. Wu, 2006, “Effects of Cure Cycles on Void Content and Mechanical Properties of Composite Laminates,” Composite Structures, Vol. 73, No. 3, pp. 303–309.
Loyd, P.A., 1989, “Ultrasonic System for Imaging Delaminations in 19 Composite Materials,” Ultrasonics, Vol. 27, No. 1, pp. 8–18.
Mokhtari, A., and F. Honarvar, 2013, “New Indices for Plotting C-scan Images Obtained from Ultrasonic Testing of Adhesive Joints,” Materials Evaluation, Vol. 71, No. 9, pp. 1081–1089.
Margetan, F.J., J. A. Gray, and R. B. Thompson, 1992, “Microstructural Noise in Titanium Alloys and Its Influence On the Detectability of Hard-Alpha Inclusions,” in D. O. Thompson, and D. E. Chimenti (eds.), Review of Progress in Quantitative Nondestructive Evaluation, Vol. 11, Plenum, New York, p. 1717.
Otsu, N., 1979, “A Threshold Selection Method from Gray-Level Histograms,” IEEE Transactions on Systems, Man, and Cybernetics, Vol. SMC-9, No. 1, pp. 62–66.
Poudel, A., and J. S. Chu, 2013, “Air-Coupled Ultrasonic Testing of Carbon-Carbon Composite Aircraft Brake Disks,” Materials Evaluation, Vol. 71, No. 8, pp. 987–994.
Rose, J.L., 1984, “Elements of a Feature-Based Ultrasonic Inspection System,” Materials Evaluation, Vol. 42, No. 2, pp. 210–218.
Scarponi, C., and G. Briotti, 2000, “Ultrasonic Technique for the Evaluation of Delaminations on CFRP, GFRP, KFRP Composite Materials,” Composites Part B: Engineering, Vol. 31, No. 3, pp. 237–243.
Sternberg, S.R., 1986, “Grayscale Morphology,” Computer Vision, Graphics and Image Processing, Vol. 35, pp. 333–355.
Tian, Q., L. Xing, and N.M. Bilgutay, 1995, “Multiple Target Detection Using Split Spectrum Processing and Group Delay Moving Entropy,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 42, No. 6, pp. 1076–1086.
Tittmann, B.R., and R. Crane, 2000, “Ultrasonic Inspection of Composites,” in A. Kelly and C. Zweben (eds.), Comprehensive Composite Materials, Elsevier, New York, p. 259.
56 Page Views
0 PDF Downloads
0 Facebook Shares