PSI - Issue 65

Akhmetkhanov R. S. et al. / Procedia Structural Integrity 65 (2024) 1–5 Akhmetkhanov R.S. / Structural Integrity Procedia 00 (2024) 000–000

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3. Conclusion

Thus, quantitative differences in the range from 10% (coefficient of variation) and up to 475% (kurtosis) in the case of thermal influence on the given thermograms for the cases without a defect and in the presence of a defect were revealed. The most informative criteria are peak height (temperature), kurtosis and coefficient of variation. The change in Minkowski connectivity shows the change in homogeneity of material properties. And multi-fractal spectra reflect the material structure properties and the presence of defects. In the presence of defect, the multifractal spectrum changes from mono-fractal spectrum to multifractal spectrum. The structure of the thermal field (strain) becomes more complex. The thermal field has different structural features. These methods of thermogram processing allow to identify defects in the material structure and can be used in non-destructive thermal inspection to assess the nature of loading and the moment of defects occurrence in the material under beyond-design loads. This work was funded by the RNF grant No. 20-19-00769-P. Nesteruk D.A., Vavilov V.P. Thermal control and diagnostics. Textbook for training of specialists of I, II, III level. Tomsk, 2007. 104 p. Moiseychik A.E., Moiseychik E.A. Fundamentals of thermal control of load-bearing structures using deformation heat generation// Non destructive testing and diagnostics, No.3, 2014. pp. 3-19 U. Galietti, D. Palumbo Thermoelastic stress analysis of titanium components and simultaneous assessment of residual stress. Politecnico di Bari, Dipartimento di Ingegneria Meccanica e Gestionale, Viale Japigia 182, Bari, Italy. 2010 ( DOI:10.1051/epjconf/20100638015) Rajic N., Rowlands D. Thermoelastic stress analysis with a compact low- cost microbolometer system// Quantitative InfraRed Thermography Journal, vol. 10, No 2, 2013. 135-158 p.: DOI: 10.1080/17686733.2013.800688, httpV/dx.doi.org/l0.1080/17686733.2013.800688 P. Servais, N. Gerlach.Development of a NDT method using thermography for composite material inspection on aircraft using military thermal imager. Vth International Workshop Advances in Signal Processing for Non Destructive Evaluation of Materials. Québec City (Canada), 2005. Muflih Alhammad, Nicolas P. Avdelidis, Clemente Ibarra-Castanedo. Maldgue Automated Impact Damage Detection Technique for Composites Based on Thermographic Image Processing and Machine Learning Classification . Sensors , V. 22, 2022. 1-21 p. https://doi.org/10.3390/s22239031 Poyarkova E.V. Physical Nature of Damages of Structural Materials from the Position of Fractal Determinism/Materials of the All-Russian Scientific and Methodical Conference, 3-5 Feb. 2016, Orenburg, OGU, 2016. pp. 205-209 Pavlov A.N., Anishchenko V.S. Multifractal analysis of complex signals. Uspekhi fizicheskikh nauki.. No.8, 2007. P. 859-876 Schroeder M. Fractals, chaos, power laws. Miniatures from infinite paradise.- Izhevsk: SIC "Regular and Chaotic Dynamics". 2001. 528 p. Akhmetkhanov R.S. Thermal control. multifractal distribution of local plastic deformations//Problems of mechanical engineering and machine reliability. 2023. No. 5. pp. 59-67 References