PSI - Issue 37

A. Vshivkov et al. / Procedia Structural Integrity 37 (2022) 570–575 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 6. Characteristic results of compare between cluster analysis of acoustic emission data and thermal measurement for 7.5 kN (a) and 8 kN load. 6. Conclusion An experimental assessment of the energy balance in the CVN-specimens of titanium alloy Grade 2 under cyclic deformation mode has been carried out. It was show that in the Paris regime the heat dissipation at the crack tip can be divided in two regimes. The first one is characterized by the constant value of heat dissipation form the crack tip. The second regime corresponds to the sharp rise of heat flux. The critical value of the stored energy tends to a certain general value. It is approximately the same for two different values of loading. The rate of stored energy per cycle slows down at the final stage of deformation. It was show that the stored energy can be the criteria of fatigue fracture. Cluster analysis of the acoustic emission signal allows us to identify two most probable clusters. One of them is present throughout the test, the second appears later. The correlation between the acoustic emission energy and heat dissipation was found to be a harbinger of the approaching transition from stable to unstable crack growth. The joint application of the presented methods could be useful in the design of intelligent systems for monitoring the state of structures and mechanisms. Acknowledgements The research was supported by RSF (project No. 19-77-3008). References Ivanova, V.S., Terentiev, V.F., 1975. The nature of the fatigue of metals. Metallurgy, Moscow. Fedorov, V.V., 1979. Thermodynamic aspects of strength and fracture of solids. FAN Uz SSR, Tashkent. Meneghetti G., 2007. Analysis of the fatigue strength of a stainless steel based on the energy dissipation. Int. J. Fatigue 29, 81 – 94. Sih GC, Gdoutos EE., 1992. Mechanics and physics of energy density. Dordrecht: Kluwer Academic. Botvina, L.R., Soldatenkov, A.P., Levin, V.P., Tyutin, M.R., Demina, Y.A., Petersen, T.B., Dubov, A.A., Semashko, N.A., 2016. Assessment of mild steel damage characteristics by physical methods. Russian metallurgy (Metally) 1, 23-33. Carpinteri, A., Lacidogna, G., Corrado, M., Di Battista, E., 2016. Cracking and crackling in concrete-like materials: A dynamic energy balance. Engineering Fracture Mechanics 155, 130-144. Bowler N., 2006. Theory of four point direct current potential drop measurements on a metal plate. Research in Nondestructive Evaluation 17, 29-48.