Nondestructive Testing of Thermal Barrier Coated
Turbine Blades using Microwave Techniques
Publication: Publication Date: 1 April 2016Testing Method:
Zirconia-based thermal barrier coatings (TBCs) are
widely used to protect turbine blades against hightemperature
and pressurized steam, increasing the
lifetime of the whole system. A turbine blade
crack, which normally begins from the metal
surface due to corrosion and stress, must be
inspected nondestructively to avoid catastrophic
failure. Although there are several established
nondestructive testing (NDT) techniques available,
microwave testing using a broad frequency sweep
with an open-ended rectangular waveguide energy
launch, in conjunction with signal processing, is
proposed in this paper as an inspection technique.
Electromagnetic signals at microwave frequencies
are capable of providing inspection of metals
coated with dielectric materials such as TBC. In
this paper, the principle of this technique is
described, along with 3D electromagnetic software
simulation using various measurement scenarios
and a number of measurements of representative
turbine blade models with discontinuities on the
metal surface, visibly hidden by the TBC. This
research is aimed at delivering an in-situ
microwave test capable of detecting surface and
subsurface discontinuities and may form part of
quality control in manufacturing as well as portable
field service inspection. As such, the system is
comparable in size to current NDT systems, as well
as robust, affordable, and capable of providing
real-time data about the nature of an anomaly
such as discontinuity location and size.
- Anuar, N.K., W.T. Wui, D.K. Ghodgaonkar, and M.N. Taib, “Use of Microwave Nondestructive Testing (NDT) Technique to Characterize the Film for Applications in Transdermal Drug Delivery System,” Proceedings of the 2005 Asian Conference on Sensors and the International Conference on New Techniques in Pharmaceutical and Biomedical Research, 5–7 September 2005, pp. 31–33.
- Bakhtiari, S., S.I. Ganchev, and R. Zoughi, “Open-ended Rectangular Waveguide for Nondestructive Thickness Measurement and Variation Detection of Lossy Dielectric Slabs Backed by a Conducting Plate,” IEEE Transactions on Instrumentation and Measurement, Vol. 42, No. 1, 1993, pp. 19–24.
- Bakhtiari, S., N. Qaddoumi, S.I. Ganchev, and R. Zoughi, “Microwave Noncontact Examination of Disbond and Thickness Variation in Stratified Composite Media,” IEEE Transactions on Microwave Theory and Techniques, Vol. 42, No. 3, 1994, pp. 389–395.
- Ganchev, S.I., J. Bhattacharyya, S. Bakhtiari, N. Qaddoumi, D. Brandenburg, and R. Zoughi, “Microwave Diagnosis of Rubber Compounds,” IEEE Transactions on Microwave Theory and Techniques, Vol. 42, No. 1, 1994, pp. 18–24.
- Gao, B., H. Zhang, W.L. Woo, G.Y. Tian, L.B. Bai, and A.J. Yin, “Smooth Nonnegative Matrix Factorization for Defect Detection Using Microwave Nondestructive Testing and Evaluation,” IEEE Transactions on Instrumentation and Measurement, Vol. 63, No. 4, 2014, pp. 923–934.
- Ghasr, M.T., D. Simms, and R. Zoughi, “Multimodal Solution for a Waveguide Radiating into Multilayered Structures – Dielectric Property and Thickness Evaluation” IEEE Transactions on Instrumentation and Measurement, Vol. 58, No. 5, 2009, pp. 1505–1513.
- Guorong, S., Y. Tianting, H. Cunfu, Y. Shen, L. Yan, and W. Bin, “Detection of Surface Crack on the Substrate under Thermal Barrier Coatings Using Microwave Non-Destructive Evaluation,” Journal of Microwave Power and Electromagnetic Energy, Vol. 49, No. 2, 2015, pp. 69–75.
- Ida, N., Microwave NDT (Developments in Electromagnetic Theory and Applications), Springer, Dordrecht, Netherlands, 1992.
- Jundi, A.J., and N.N. Qaddoumi, “Open-ended Rectangular Waveguide Near-field Frequency Response of Multilayered Structures,” Proceedings of the 5th European Conference on Antennas and Propagation, 11–15 April 2011, pp. 1304–1308.
- Kharkovsky, S., and R. Zoughi, “Microwave and Millimeter Nondestructive Testing and Evaluation – Overview and Recent Advances,” IEEE Instrumentation & Measurement Magazine, Vol. 10, No. 2, 2007, pp. 26–38.
- Li, Z., A. Haigh, C. Soutis, A. Gibson, R. Sloan, and N. Karimian, “Detection and Evaluation of Damage in Aircraft Composites using Electromagnetically Coupled Inductors,” Composite Structures, Vol. 140, April 2016, pp. 252–261.
- McClanahan, A., S. Kharkovsky, A.R. Maxon, R. Zoughi, and D.D. Palmer, “Depth Evaluation of Shallow Surface Cracks in Metals using Rectangular Waveguides at Millimeter-wave Frequencies,” IEEE Transactions on Instrumentation and Measurement, Vol. 59, No. 6, 2010, pp. 1693–1704.
- Miranda, F.A., W.L. Gordon, V.O. Heinen, B.T. Ebihara, and K.B. Bhasin, “Measurements of Complex Permittivity of Microwave Substrates in the 20 to 300 K Temperature Range from 26.5 to 40.0 GHz, 0–9,” NASA-TM-102123, NASA Lewis Research Center, 1990.
- Ostadrahimi, M., A., Zakaria, J. Lovetri, and L. Shafai, “A Near-field Dual Polarized (TE-TM) Microwave Imaging System,” IEEE Transactions on Microwave Theory and Techniques, Vol. 61, No. 3, 2013, pp. 1376–1384.
- Padture, N.P., M. Gell, and E.H. Jordan, “Thermal Barrier Coatings for Gas-turbine Engine Applications,” Science, Vol. 296, No. 5566, 2002, pp. 280–284.
- Shull, P.J., Nondestructive Evaluation: Theory, Techniques, and Applications, Marcel Dekker, New York, New York, 2002.
- Thompson, D.P., A.M. Dickins, and J.S. Thorp, “The Dielectric Properties of Zirconia,” Journal of Materials Science, Vol. 27, No. 8, 1992, pp. 2267–2271.
- Valiente, L.A., A.D. Haigh, A.A.P. Gibson, G. Parkinson, G. Jacobs, P.J. Withers, and R. Cooper-Holmes, “Coplanar Waveguide Scanning Microwave Profiler,” Proceedings of the 37th European Microwave Conference, 9–12 October 2007, pp. 194–197.
- Valiente, L.A., A.D. Haigh, A.A.P. Gibson, G. Parkinson, P.J. Withers, and R. Cooper-Holmes, “Scanning Microwave Profiler,” Proceedings of the 36th European Microwave Conference, 10–15 September 2006, pp. 718–721.
- Yang, S.H., K.B. Kim, and J.S. Kang, “Detection of Surface Crack in Film-coated Metals using an Open-ended Coaxial Line Sensor and Dual Microwave Frequencies,” NDT&E International, Vol. 54, March 2013, pp. 91–95.
- Zhang, H., B. Gao, G.Y. Tian, W.L. Woo, and L. Bai, “Metal Defects Sizing and Detection under Thick Coating using Microwave NDT,” NDT&E International, Vol. 60, December 2013, pp. 52–61.
- Zhang, H., B. Gao, G.Y. Tian, W.L. Woo, and A. Simm, “Spatial-frequency Spectrum Characteristics Analysis With Different Lift-offs for Microwave Nondestructive Testing and Evaluation using Itakura-Saito Nonnegative Matrix Factorization,” IEEE Sensors Journal, Vol. 14, No. 6, 2014, pp. 1822–1830.
- Zoughi, R. Microwave Non-destructive Testing and Evaluation Principles, Springer, Dordrecht, Netherlands, 2000.
- Zoughi, R., and S. Bakhtiari, “Microwave Nondestructive Detection and Evaluation of Disbonding and Delamination in Layered-dielectric Slabs,” IEEE Transactions on Instrumentation and Measurement, Vol. 39, No. 6, 1990, pp. 1059–1063.
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