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Crack Detection of Ceramics based on Laser Speckle Photometry
B. Bendjus, U. Cikalova, L. Chen
Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Maria-Reiche-Str. 2, 01109 Dresden.
received October 28, 2016, received in revised form December 20, 2016, accepted January 24, 2017
Vol. 8, No. 1, Pages 73-80 DOI: 10.4416/JCST2016-00090
Abstract
Ceramic components subjected to increasingly extreme conditions are being pushed to their performance limits. That is, the critical crack length for alumina is less than 80 µm. Therefore, to guarantee and estimate the quality of ceramics, new advanced nondestructive diagnostics methods with high resolution are required.
Laser Speckle Photometry is an innovative optical non-destructive and monitoring technique based on the detection and analysis of thermally or mechanically activated characteristic speckle dynamics in the non-stationary optical field. When an object is excited by an external thermal source, the thermal energy propagation causes a local temperature difference, which generates local thermal expansion. The local thermal expansion excites speckle movement, which can be detected by a fast digital camera. The objective of the paper is to examine the suitability of the LSP technique for the detection of micro-cracks located on the surface of ceramics. Results of measurements with different experimental parameters are presented by means of the imaging LSP method. It shows that LSP is a suitable approach for detecting cracks in ceramics. The results of successful evaluations show that the detectable resolution of the LSP technique at the current research stage is approximately 500 µm in terms of the length of cracks.
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Keywords
Ceramics, speckles, micro-crack detection, non-destructive optical testing
References
1 Bengisu, M.: Engineering ceramics. Springer, Berlin, 2001.
2 Cripps, Anthony C: Chapter 2: Linear elastic fracture mechanics. introduction to contact mechanics. 2nd ed. New York: Springer, 2007. 31 – 48.
3 Cikalova, U., Bendjus, B., Schreiber, J.: Laser-Speckle-photometry – A method for non-contact evaluation of material damage, hardness and porosity, Materialprüfung, 54, [2], 80 – 84, (2012).
4 Cikalova, U., Bendjus, B., Schreiber, J.: Material characterization by laser speckle photometry. Speckle 2012: V. Proceedings of the International Conference on Speckle Metrology (2012).
5 Cikalova, U., Bendjus, B., Schreiber, J.: Laser speckle photometry: Contactless nondestructive testing technique. Speckle 2012: V. Proceedings of the International Conference on Speckle Metrology (2012).
6 Goodman, Joseph W.: Statistical properties of laser speckle patterns. In: Laser speckle and related phenomena, Springer, New York, 9 – 75, 1975.
7 Goodman, Joseph W.: Statistical optics. Wiley VCH, New York, 1985.
8 Nicolai, J., Cikalova, U., Bendjus, B., Schreiber, J.: Laser-speckle-photometry – A method for the fast and non-contact determination of material states, (in German), in: Pragram poster with short presentation, DGZfP Annual Meeting, 2013, Dresden, Germany (2013), Poster 64
9 Tzou, D.Y.: Macro-to microscale heat transfer: The lagging behavior. Second ed. Wiley VCH, New York, 282 – 288, 2014.
10 Kazak, N. S., Khilo, N. A., Maschenko, A. G., Ropot, P. I., Mukhurov, N. I., Schreiber, J.: Speckle-photometry method of measuring the coefficient of thermal diffusion, in: International Conference Optical Techniques and Nano-Tools for Material and Life Sciences 1, Minsk, Belarus, 61 – 72, 2010.
11 Mazzella, A., Mazzella, A.: The importance of the model choice for experimental semivariogram modeling and its consequence in evaluation process, Journal of Engineering, 2013, 1 – 10, (2013)
12 Cikalova, U., Bendjus, B., Schreiber, J.: Material characterization by laser speckle photometry. In Proc. SPIE 8413, Speckle 2012: V. Proceedings of the International Conference on Speckle Metrology, SPIE Press, Bellingham, Washington, 2012.
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