Browsing by Author "Hrechana, A."

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    Determination of the Critical Cyclic Fracture Toughness for the Mode II in Mixed Fracture of Structural Steels
    (Elsevier Ltd., Oxford, 2023) Belodedenko, Sergii V.; Hrechanyi, Oleksii. M.; Vasilchenko, T.; Hrechana, A.; Izhevskyi, Y.
    ENG: The developed method of processing experimental data from tests performed according to the four-point asymmetric bending scheme made it possible to establish the coefficient of proportionality between the modes of failure I and II, which for structural steels is in the range of 2,5÷3. The established longevity before the appearance of the critical speed according to the developed models is within the limits of the natural dispersion inherent in fatigue failure, which indicates the effectiveness of the developed algorithm and the correctness of the determined indicators of resistance to failure. The problem of the appearance of an oblique crack during tests on four-point asymmetric bending has been solved. It can be assumed that about 90% of the growth of an oblique crack is caused by the contribution of the mode of failure II.
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    Development of a Methodology for Mechanical Testing of Steel Samples for Predicting the Durability of Vehicle Wheel Rims
    (Elsevier B.V., 2023) Belodedenko, Sergii V.; Hrechanyi, Oleksii. M.; Vasilchenko, T.; Baiul, Kostiantyn V.; Hrechana, A.
    ENG: The reliability and durability of parts of aggregates and mechanisms of motor vehicles depend on the efficiency of the basic and responsible load-bearing structures. The responsible elements of the motor vehicle are the wheel rims, whose reliability will increase the energy efficiency of the motor vehicle as a whole. One of the directions for increasing the reliability of wheel rims is the use of optimized low-pearlite steels with the increased impact strength of the 10HFTBch type. When determining the mechanical characteristics of steels with increased impact strength, it is worth considering a mixed form of failure; therefore, the scheme of four-point asymmetric bending is optimal for laboratory research. Conditions of mixed failure for an oblique crack lead to a 25–45% decrease in the value of ΔКІm* relatively to the stress intensity factor ΔКІ* obtained for the pure I mode. The same can be said about the II mode, when ΔКІІ* determined during the growth of an oblique crack is 10% smaller than the value of ΔКІІ*, which is calculated for the pure mode of failure, This indicates an increase in the fatigue crack growth rate for mixed failure compared to pure modes.