Кафедра Галузеве машинобудування ДМетІ (з 2022 р. утворилась шляхом з'єднання кафедри Колісних і гусеничних транспортних засобів та кафедри Машини та агрегати металургійного виробництва)

Permanent URI for this communityhttp://crust.ust.edu.ua/handle/123456789/16490

ENG: Faculty of Machine Design and Environmental Protection Dnipro Metallurgical Institute

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Advancement of Risk Analysis Methods during Prolonging the Service Life of Industrial Equipment
(Springer Nature Switzerland AG, 2023) Belodedenko, Sergii V.; Bilichenko, Galyna M.; Hanush, Vasyl I.; Izhevskyi, Y.
ENG: The aim of the work was to trace the relationship between the durability of the equipment and its maintenance strategy. This is done by examples of basic structures of industrial equipment. They have a long service life and during this time manage to accumulate certain damages that need to be diagnosed, after which decisions on its maintenance and repair must be made. Problems associated with the technique for extending the service life of industrial equipment are addressed. The authors have created a technique called the resource safety index (RSI), which uses this characteristic as a diagnostic metric. The usage of the risk function to control the technical state of base structures is shown in this study. It is demonstrated how the behavior of the risk function afects the choice of the inspection model. A risk function model for base structures is proposed, which is based on the concepts of stepwise assignment of the limit state and the corresponding useful life. An algorithm for determining the optimal period of restoration measures according to minimizing the cost intensity criterion, where the risk indicator is a parameter, has been developed. The proposed concepts were put into practice when deciding on the further operation of the housings of the 350 pipes rolling unit. The housings of the piercing mill and the automatic mill, which had been in operation for 80 years, were diagnosed. For the frst time, it was discovered that the housings risk function at the crack break through point stage can be represented by a linear dependence directly proportional to the accumulation of operating time. One of the signs of deterioration in the technical condition of rolling mill stands is a malfunction of the system of fxing and securing the housings.
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.
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.
Engineering Safety in the Aspect of the Safety and Security Civilization
(Maximum Academic Press, 2025) Belodedenko, Sergii V.; Bilichenko, Galyna M.; Rassokhin, Dmytro
ENG: The present article is devoted to the methods of quantitative risk analysis used to ensure the engineering safety of industrial equipment. It aims to clarify the latter's place in the concept of the civilization of safety and security. The features that make engineering universal in engineering are its interdisciplinary nature and the presence of a safety culture. Interdisciplinarity is manifested when considering organizational and legal factors for risk assessment. This is demonstrated by the example of two blast furnace accident scenarios. The safety culture is implemented through initiative-taking maintenance strategies through risk-based maintenance. The theoretical foundations of this strategy are presented: risk and safety indicators, an algorithm for finding the optimal level of risk, and a method for diagnosing the technical condition of mechanical systems. Recommendations on using risk and safety indicators depending on the criticality of the element being diagnosed are given.
Experimental and Analytical Ways of Finding the Function of the Maximum Accumulated Damage under Operating Modes with Overloads
(Elsevier B.V., Amsterdam, Netherlands, 2024) Belodedenko, Sergii V.; Hrechanyi, Oleksii M.; Hanush, Vasyl I.; Izhevskyi, Y.
ENG: The problem of overloading was characterized as a factor of load history in the modern resource assessment methodology. The signs by which a loading cycle can be considered an overload were defined. A correlation was obtained between the failure mechanics approach and the damage accumulation approach to survivability prediction. An experimental and analytical method of its adjustment has been developed based on the regularities of the impact of loads on the accumulated damage. Its use in obtaining models of damage accumulation in 40Cr and 35CrMnSi steels was shown. New experimental data were obtained on the behavior of the accumulated damage function in the stress localization zones during bending, and an explanation of its non-monotonicity under the influence of operational factors was found.
Fatigue Behavior of Steels for Critical Members and Durability Models with Stress Ratio Growth
(Elsevier B.V., 2026) Belodedenko, Sergii V.; Hrechanyi, Oleksii M.; Scherbinin, M.
ENG: The use of high-strength steels allows you to reduce the weight of the object, increase reliability and safety. Authors offer a new interpretation of critical members based on risk analysis and the concept of safety. Their performance determines the level of losses during the operation of mechanical systems. Critical members made of high-strength steels can be subjected to cyclic loading with a high stress coefficient. Known disadvantage of high-strength steels is their vulnerability to most impact factors, including cyclic loading with high cycle asymmetry. Cylindrical samples of heat-treated steels 09Cr16Ni4Nb and 13Cr15Ni4NМо3 were tested for tensile fatigue. Test results were presented in the form of a durability equation. Smith charts in relative stresses were obtained by simple transformations from a durability equation. Obtained charts showed a somewhat anomalous concave shape instead of an expected convex. This indicates a loss of sensitivity to mean stresses at high cycle asymmetry. Authors explain this phenomenon from the point of view of combining the concepts of fatigue and fracture mechanics. Model of a durability equation is proposed based on the concept of combining fracture mechanics and fatigue methodology. Its application in practice is a priori and requires assigning only one parameter in the form of the slope of the S-N curve.
The Features of Fatigue Resistance of Critical Members Steels under High Stress Ratio
(Elsevier B.V., 2026) Belodedenko, Sergii V.; Bilichenko, Galyna M.; Hanush, Vasyl I.; Hrechanyi, Oleksii M.
ENG: From the standpoint of risk analysis and the concept of safety, the authors propose a new interpretation of critical members. Their performance determines the level of losses during the operation of mechanical systems. Therefore, it is advantageous to make critical members from high-strength steels that are sensitive to most influencing factors. Elements made of high-strength steels suffer from cyclic load with high stress ratio. In this aspect, cylindrical samples of heat-treated 09Cr16Ni4Nb and 13Cr15Ni4Мо3 steels were tested for tensile fatigue. The test results were presented in the form of a lifetime equation. Smith diagrams in coordinates were obtained by simple transformations from lifetime equation. These graphs showed a slightly anomalous concave shape instead of the expected convex shape. This indicates a loss of sensitivity to mean stress at high stress ratio. The authors explain this phenomenon from the standpoint of the merging of fatigue and fracture mechanics concept. Interestingly, a similar form was obtained for the graph of the dependence of the critical cyclical SIF on stress ratio. That is, the sensitivity of cyclic toughness to the value of the stress ratio decreases as it increases.