The goal of this study is to improve the time resolution of linear chirp ultrasonic testing by employing frequency-phase-amplitude modulation excitation, combined with pulse compression. The proposed coded signal is a blackman-windowed linear chirp signal with 13-bit barker code, in which a blackman-windowed chirp signal is applied on every subpulse of barker code. Compared with linear chirp excitation, pulse compression output of the proposed excitation suppresses the side lobe better and decreases the main lobe width. As a result, time resolution is improved. The proposed coded signal performance of improving the time resolution is studied via numerical and experimental investigations. The simulation is implemented using a proprietary computing K-wave toolbox. The effects of chirp bandwidth and duration on the proposed coded signal excitation are then analyzed based on the simulation mode. The simulation results show that chirp bandwidth has less impact on proposed coded signal excitation than chirp excitation. The proposed coded signal is more suited to an ultrasonic exciting signal. In order to investigate the actual performance of chirp-B13-BW excitation in weld ultrasonic testing, experiments are conducted to test discontinuities in carbon steel weld samples. The obtained results show that the time resolution increases significantly by the employment of chirp-B13-BW excitation, compared with conventional brief pulse excitation and chirp excitation.
Behradfar, E., A. Mahloojifar, and A.E. Behradfar, 2009, “Performance Enhancement of Coded Excitation in Ultrasonic B-Mode Images,” Second International Conference on Machine Vision, Dubai, United Arab Emirates.
Brenner, A.R., K. Eck, W. Wilhelm, T.G. Noll, 1997, “Improved Resolution and Dynamic Range in Medical Ultrasonic Imaging Using Depth-Depen-dent Mismatched Filtering,” 1997 Ultrasonics Symposium, 1997, Toronto, Canada, Vol. 2.
Cong, S., T. Gang, and J.-Y. Zhang, 2015, “Ultrasonic Time-of-Flight Diffraction Testing with Linear Frequency Modulated Excitation for Austenitic Stainless Steel Welds,” Journal of Nondestructive Evaluation, Vol. 34, No. 2, p. 8.
Firouzi, K., B.T. Cox, B.E. Treeby, and N. Saffari, 2012, “A First-Order k-Space Model for Elastic Wave Propagation in Heterogeneous Media,” The Journal of the Acoustical Society of America, Vol. 132, No. 3, pp. 1271–1283.
Gang, T., Z.Y. Sheng, and W.L. Tian, 2012, “Time Resolution Improve-ment of Ultrasonic TOFD Testing by Pulse Compression Technique,” Insight-Non-Destructive Testing and Condition Monitoring, Vol. 54, No. 4, pp. 193–197.
Isla, J., and F. Cegla, 2016, “Coded Excitation for Low SNR Pulse-Echo Systems: Enabling Quasi-Real-Time Low-Power EMATs,” IEEE Ultra-sonics Symposium IEEE, Tours, France.
Isla, J., and F. Cegla, 2017, “EMAT Phased Array: A Feasibility Study of Surface Crack Detection,” Ultrasonics, Vol. 78, pp. 1–9.
Izadi, S.A., A. Mahloojifar, and B.M. Asl, 2015, “Weighted Capon Beam-former Combined with Coded Excitation in Ultrasound Imaging,” Journal of Medical Ultrasonics, Vol. 42, No. 4, pp. 477–488.
Kiefer, D.A., M. Fink, and S.J. Rupitsch, 2017, “Simultaneous Ultrasonic Measurement of Thickness and Speed of Sound in Elastic Plates Using Coded Excitation Signals,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 64, No. 11, p. 1744-1757.
Li, C.-Z., F.-F. Shi, and B.-X. Zhang, 2012, “Research on LFM Signals in Steel Materials,” 2012 Symposium on Piezoelectricity, Acoustic Waves and Device Applications (SPAWDA), Shanghai, China.
Li, H., and Z. Zhou, 2017, “Air-Coupled Ultrasonic Signal Processing Method for Detection of Lamination Defects in Molded Composites,” Journal of Nondestructive Evaluation, Vol. 36, No. 45.
Mahafza, B.R., 2002, Radar Systems Analysis and Design Using MATLAB, CRC Press, Boca Raton, FL.
Michaels, J.E., S.J. Lee, A.J. Crawford, and P.D. Wilcox, 2013, “Chirp Excitation of Ultrasonic Guided Waves,” Ultrasonics, Vol. 53, No. 1, pp. 265-270.
Misaridis, Thanassis X., K. Gammelmark, C. Jorgensen, N. Lindberg, A. Thomsen, M. Pedersen, and J. Jensen, 2000, “Potential of Coded Excita-tion in Medical Ultrasound Imaging,” Ultrasonics, Vol. 38, No. 1, pp. 183–189.
Nowicki, A., J. Litniewski, W. Secomski, P.A. Lewin, and I. Trots, 2003, “Estimation of Ultrasonic Attenuation in a Bone Using Coded Excitation,” Ultrasonics, Vol. 41, No. 8, pp. 615–621.
Sanchez, J.R., D. Pocci, and M.L. Oelze, 2009, “A Novel Coded Excitation Scheme to Improve Spatial and Contrast Resolution of Quantitative Ultra-sound Imaging,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 56, No. 10.
Treeby, B.E., J. Janos, D. Rohrbach, and B.T. Cox, 2014, “Modelling Elastic Wave Propagation Using the K-Wave MATLAB Toolbox,” 2014 IEEE International Ultrasonics Symposium (IUS), Chicago, IL.
Treeby, B.E., and B.T. Cox, 2010, “k-Wave: MATLAB Toolbox for the Simulation and Reconstruction of Photoacoustic Wave Fields,” Journal of Biomedical Optics, Vol. 15, No. 2, p. 021314–021314.
Zeng, L., and J. Lin, 2014, “Chirp-based Dispersion Pre-Compensation for High Resolution Lamb Wave Inspection,” NDT & E International, Vol. 61, pp. 35–44.
Zhou, Z., B. Ma, J. Jiang, and W. Liu, 2014, “Application of Wavelet Filtering and Barker-Coded Pulse Compression Hybrid Method to Air-Coupled Ultrasonic Testing,” Nondestructive Testing and Evaluation, Vol. 29, No. 4, pp. 297–314.
203 Page Views
0 PDF Downloads
0 Facebook Shares