Browsing by Author "Stotsko, Z. A."
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Item Determination of the Optimal Parameters of the Structure of Functional Gradient Materials using Mathematical Modelling Approaches(International OCSCO World Press, Poland, 2019) Lyashenko, B. A.; Stotsko, Z. A.; Kuzin, Oleg A.; Kuzin, Mykola O.; Mikosianchyk, OksanaEN: Abstract. Purpose: Functioning of mechanical friction systems largely depends on the characteristics of the structure of their surface layers. By controlling these parameters, it is possible to significantly adjust the reliability and durability of parts under the conditions of contact interaction. Design/methodology/approach: he proposed approach, which is based on the principle of nonlocality of the operational properties of materials, allows determining the optimal microhardness values of the surface layers and the gradient of this parameter, at which the contact durability of friction pair elements significantly increases. Findings: It is established that by adjusting the ratios of the surface strength of materials and its gradient, it is possible to achieve a significant increase in the operational parameters of friction units. Practical implications: The engineering relationship considered in the work allows to establish functional distributions of microhardness in the structure of surface layers, at which their wear reaches minimum values. Originality/value: Mathematical approaches are proposed, which allow determining the parameters of the structure of the surface layers of parts to increase their durability under conditions of friction contact loads.Item Life Cycle Assessment of Technical Systems Taking into Consideration Degradation Processes in Materials of Constructions(International OCSCO World Press, Poland, 2018) Stotsko, Z. A.; Kuzin, Mykola O.EN: Purpose: In the engineering analysis and transport forensic examination, there are often arise problems in establishing the causes and mechanism for the destruction of structural elements. At the moment, such problems are poorly formalized and practically do not take into account the degradation of the material and the gradient of its properties when destroyed. The purpose of this article was to build a methodology for determining the distribution of material properties at the initial time and establishing its compliance with the requirements of regulatory documentation. Design/methodology/approach: As a technique for solving the problem, was proposed the expansion of a function in a given basis with subsequent refinement of the solution using iterative algorithmic schemes. Findings: Using the developed approaches, it is established that in the surface layers of 12X18H10T steel (AISI 321), after technological modification under the conditions of laser doping, functional-gradient layers are formed with the material viscosity level characteristics at 0.8, which corresponds to the established norms, and their destruction occurred as a result of excessive loads. Practical implications: With the using of the developed methods makes it possible to solve the problem of technical forensic examination to determine compliance to the requirements the properties of functional gradient materials in initial time. Originality/value: The technique of solving inverse problems of fracture mechanics for functional gradient materials is shown for the first time.Item Use of Modern Tribology Approaches for Correcting the Behaviour of Adaptive Biomechanical Friction Units(International OCSCO World Press, Poland, 2018) Stotsko, Z. A.; Kuzin, Oleg A.; Kuzin, Mykola O.EN: Purpose: Functioning of mechanical system friction units is characterized by the ability of their self-adaptation under the influence of external loads. Referring to this phenomenon it becomes possible to provide the necessary correction of the work of friction units being parts of artificial and natural tribosystems. Design/methodology/approach: As an approach used to solve the above problem, an expansion of the function describing friction unit parameters in a given basis with further refinement of the solution in accordance with the functional optimization is proposed. Findings: The received ratios allow solving the problem of adaptive control of friction units functioning when they are incorporated into the biomechanical systems. Practical implications: Using approaches developed in the present work, a pattern for the gradual adjustment of instep supports for the restoration of normal weight distribution in the human foot is presented. Originality/value: Novel approaches to the methodology of solving the problem in regard of managing the load condition of biomechanical tribosystems by their commanded control over time are offered.