PSI - Issue 20

Yakovleva S. P. et al. / Procedia Structural Integrity 20 (2019) 154–160 Yakovleva S. P. et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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damage of the different structural and scale levels, represented by the crystalline structure defects (microdamage) and porosity (mesodamage), are identified. 2. The comparison of the results of the structural and statistical analysis of the metal of the spring zones with the different damage levels showed that the pre-failure zone at the intermediate values of the microdamage accumulation coefficient and volume fraction of the mesodamage (the pores) is characterized by the lower value of the microhardness due to the softening; the deviation of the law of the microhardness distribution from the Gaussian law; the significant prevalence of the fine pores (by ≈47%); and the much smaller quantity of the coarse pores (by ≈45%). 3. The fatigue damage accumulated in the spring before its operational failure did not lead to metal embrittlement: the impact toughness values indicate the satisfactory resistance of the metal to the brittle fracture at the low temperatures of the climatic range, and the temperature dependence of the impact toughness is largely determined by the mesodamage level. 4. The new results were obtained on the insufficiently studied processes of the fatigue damage accumulation under the unsteady loads, their influence on the brittle fracture resistance and a rationale was given for the greater significance of the road microprofile as the destructive factor for the leaf springs operating in the cryolithozone compared to the factor of the low temperatures (up to – 45 ºС). Acknowledgements The authors are grateful to the staff of the Institute of the Physical-Technical Problems of the North, SB RAS and Yakut Scientific Center, SB RAS who helped with the experiments. The research was carried out within the state assignment of the Program of Fundamental Scientific Research of State Academies of Sciences for 2017-2020 (theme III.23.3.4) References Bhat S., Patibandla R., 2011. Metal Fatigue and Basic Theoretical Models: A Review. Alloy Steel – Properties and Use, Dr. E.V. Morales (Ed.). INTECH Open Access Publisher. 203-236. Botvina, L.R., 2008. Destruction: Kinetics, Mechanisms, Common Pattern. Nauka, Moscow, pp. 334. Karzov,G.P., Margolin,B.Z., Shvetsova, V.A., 1993. Physical and Mechanical Modeling of Fracture Processes. Politekhnika, Saint Petersburg, pp. 391. Kim, H.S., Yim, H.J., Kim, M., 2002. Computational durability of body structure in prototype vehicles. Int. J. Automotive Technol. 3 (4), 129 – 136. Makhutov, N. A.,Lebedev, M. P.,Bolshakov, A. M.,Gadenin, M. M., 2013. Scientific Basis for Analysis and Reduction of Disaster Risks in the Regions of Siberia and the North. The Arctic: ecology and economics 4 (12), 1 – 12. Matvienko,Y.G., 2014. Modeling and Fracture Criteria in Current Problems of Strength, Survivability and Machine Safety. Journal of Machinery Manufacture and Reliability 3, 242 – 249 DOI: 10.3103/S1052618814030066 Murakami Yu., 2002, Metals Fatigue: Effects of Small Defects and Nonmetallic inclusions. Elsevier Ltd, London, UK, pp. 298. Romanov, A.N., 2006. Patterns of Fatigue Failure. Metal Science and Heat Treatment 9, 19 – 27. Saedi N., Ashrafizadeh F., Niroumand B. et. al., 2014. Damage Mechanism and Modeling of Void Nucleation Process in a Ferrite-Martensite Dual Phase Steel. Engineering Fracture Mechanics. 127, 97 – 103. Sakai T., Li W., Lian B, Oguma N., 2011. Review and new analysis on fatigue crack initiation mechanisms of interior inclusion-induced fracture of high strength steels in very high cycle regime, Berger С . and Christ H.-J. (Eds). Very High Cycle Fatigue, Proc. Fifth Intern. Conf. VHCF 5. Berlin, Germany, 19-26. Sangid, M.D., 2013. The physics of fatigue crack initiation. Int. J. of Fatigue 57, 58-72. Suchkova, E.Yu., Ivakhin, M.P., Gromova, A.V. et al., 2005. Analysis of the surface fatigue fracture hardened steel 60GS2, Fundam. Probl.Sovrem.Materialoved. 1, 68 – 69. Volegov, P.S., Gribov, D.S., Trusov, P.V., 2015. Damage and fracture: review of experimental studies. Journal of Physical mesomechanics 18(3), 11-24. Yakovleva, S.P., Buslaeva, I.I., Makharova, S.N., Levin, A.I., 2017. Operational Damage to the Structure and Failure of the KAMAZ Truck Spring in the Temperature – Load Conditions of the North. Journal of Machinery Manufacture and Reliability 46(5), 488 – 493. Zorin, E.E., 2013. Development of rapid diagnostics and prediction of residual life based on detection of accumulated damage of metal structure during sustained loading. Izv. MGTU-MAMI 1(15), 142 – 148. Zorin, E.E., Zorin N.E., 2009. Operative diagnostics of the mechanical characteristics of welded structures during long-term operation on the basis of the microindentationprocess. Journal of Welding and Diagnostics 5, 25-29.