Journal of Engineering Sciences / Журнал інженерних наук
Permanent URI for this collectionhttps://devessuir.sumdu.edu.ua/handle/123456789/34326
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Item Increasing the contact strength of Bohler K490 MicroClean steel parts by determining carbonitriding conditions(Sumy State University, 2025) Довгополов, Андрій Юрійович; Dovhopolov, Andrii Yuriiovych; Колесник, Віталій Олександрович; Kolesnyk, Vitalii Oleksandrovych; Панченко, Андрій Васильович; Panchenko, Andrii Vasylovych; Некрасов, Юрій Олександрович; Nekrasov, Yurii Oleksandrovych; Дегтярьов, Іван Михайлович; Dehtiarov, Ivan Mykhailovych; Šimna, V.; Проскурня, Сергій Іванович; Proskurnia, Serhii Ivanovych; Чумаков, Дмитро Сергійович; Chumakov, Dmytro SerhiiovychThe problem of increasing the service life of various devices and units operating under high loads on parts remains open to date. Increasing the service life of these mechanisms is possible by increasing the contact strength of the material. Various thermal and chemical-thermal treatment (CTT) methods are often used to improve this parameter. This work presents the results of an experimental study of the influence of CTT parameters on the contact strength of the surface layer of high-quality powder steel Bohler K490 MicroClean. The study’s relevance is due to the need to increase the wear resistance and durability of parts of tools and machines operating under challenging conditions. The primary purpose of the work was to determine rational temperature-time conditions of carbonitriding to ensure maximum surface hardness and effective depth of the hardened layer. The research methodology included sample preparation, heat treatment, machining using Tenifer-QPQ technology at 560, 580, and 610 °C, and holding for 1–6 h. The Vickers method measured the microhardness, the carbonitrided layer depth was determined, and metallographic analysis of the microstructure was performed. The results showed the best combination of high surface hardness (up to 1434 HV0.2) and sufficient hardening depth at a temperature of 580 °C and a holding time of 6 h. Pre-hardening positively affects the formation of a dense zone, strengthening the surface layer. On the contrary, an increase in temperature to 610 °C led to a deepening of the diffusion layer, but was accompanied by a decrease in the hardness of the core. The results of this study were implemented in the practice of a machine-building enterprise in the Sumy region of Ukraine, which specializes in thermal and CTT of parts of various types.Item Mathematical modeling of the working body’s oscillatory motion in a concrete mixer(Sumy State University, 2025) Rudyk, R.Y.; Virchenko, V.V.; Salnikov, R.Y.; Kuzub, Y.O.This study investigates the concrete mixing process in a gravity mixer and proposes strategies to enhance its efficiency. The challenge of uneven component distribution, arising from passive-zone formation, was addressed through a mathematical model developed to describe particle-motion kinematics within the mixing drum. Numerical simulations demonstrated that mixing efficiency is strongly influenced by drum rotation speed, inclination angle, blade configuration, and oscillatory motion. Introducing oscillations was found to increase the intensification coefficient by 15–18 %, reduce the passive-zone area from 28 % to 15 %, and improve mixture uniformity by 12–15 % in terms of the variation coefficient. Furthermore, oscillatory motion accelerates the growth of homogeneity: a rapid increase begins as early as 2 min, reaching the mixing intensity factor 0.8 by 4 min, corresponding to high-quality mixing. In contrast, without oscillations, a comparable level of homogenization is achieved only after 6–7 min of drum operation. The findings confirmed the effectiveness of oscillatory drum motion as a practical approach to improving mixing quality, reducing energy demand, and optimizing the structural design of concrete mixers.Item DFT study of electronic and ionic transport in Li₃VBPO₇ for cathode materials(Sumy State University, 2025) Macouti, N. E. H.El; Bouanounou, M.El; Assila, A.; Hlil, E.K.; Boughaleb, Y.; Hajjaji, A.; Laasri, S.The increasing demand for high-performance lithium-ion batteries (LIBs) necessitates novel cathode materials with enhanced electronic and ionic transport properties. This study aims to evaluate the potential of Li3VBPO7 as a cathode material using density functional theory (DFT) with the CASTEP code, focusing on its electronic structure and lithium diffusion characteristics. Based on a monoclinic structure with lattice parameters (a = 5.0581 Å, b = 6.4127 Å, c = 16.9708 Å), the analysis reveals a 0.8 eV band gap in the pristine state, transitioning to 0 eV during lithium migration, indicating enhanced electronic conductivity. Nudged elastic band calculations yield a low activation energy of 0.29 eV with a diffusion coefficient of about 1.7 10–12 m2 /s and ionic conductivity of about 2.31·10–4 S/m at 300 K, suggesting efficient lithium transport. As a result, geometry optimization confirmed structural stability, while population analysis highlighted ionic bonding. These properties position Li3VBPO7 as a promising cathode for highrate LIBs, with potential applications in electric vehicles and grid storage, pending experimental validation through synthesis and electrochemical testing.Item Prediction of the total exhaust heat emission from motorcycles using a backpropagation neural network(Sumy State University, 2025) Sugiono, S.; Putro, W.W.; Swara, S.E.; Nurbi, R.S.; Rafif, A.H.; Gusti, G.I.I.; Putri A., Z.S.; Alfayyadh, M.A.The increasing number of motorcycles in Indonesia contributes significantly to traffic congestion, noise pollution, air pollution, and thermal emissions to the surrounding environment. This study develops a rapid and accurate method to predict total exhaust heat from motorcycles in real-time using a backpropagation neural network (BPNN) optimized with a genetic algorithm. The research methodology involves measuring exhaust heat from 17 motorcycle types using thermal imaging equipment across various engine speeds (2000–5000 rpm). Input parameters include motorcycle brand, engine displacement, transmission type, manufacturing year, ambient temperature, and vehicle speed, while output parameters comprise heat from the engine surface, the exhaust surface, and exhaust gas. The BPNN model achieved a mean square error of 0.01 after training on 500 datasets (70 % training, 15 % validation, 15 % testing). Results show that engine surface heat contributes 87 % of total exhaust heat, exhaust surface contributes 12 %, and exhaust gas contributes 1 %. This BPNN module enables real-time environmental heat assessment, supporting sustainable transportation planning and vehicle design improvements.Item Optimizing Miura origami for enhanced energy absorption: A multi-objective approach(Sumy State University, 2025) Kusyairi, I.; Choiron, M.A.; Purnowidodo, A.; Bintarto, R.This research addresses the critical challenge of improving structural energy absorption in crash scenarios. The study investigates the optimization of Miura origami-inspired thin-walled structures for vehicle safety systems. The structures were fabricated using AlSi10Mg aluminum alloy through selective laser melting (SLM) 3D printing technology. A frontal crash test scenario was simulated in ANSYS to assess structural performance under impact loading. The study applied a multi-objective optimization approach, combining the Taguchi method, principal component analysis (PCA), and composite desirability analysis, to evaluate the influence of design parameters such as wall thickness, number of sides, surface diameter, and number of segments. Based on the analysis of variance (ANOVA) results, wall thickness was identified as the most dominant factor, contributing 67 % to energy available (EA), while surface diameter and number of sides contributed 14 % and 7 %, respectively. The number of segments had a minor effect, contributing only 0.5 % to EA. The optimal configuration t3n1d3M2 was further validated through compression testing of 3D-printed prototypes, with deformation behavior analyzed using digital image correlation (DIC). The experimental findings closely matched simulation outcomes, confirming the robustness of the proposed optimization framework. These results provide valuable insights into integrating origami-inspired geometries and advanced additive manufacturing for enhanced crashworthiness in automotive structures.Item Natural coagulant efficiency of Moringa oleifera seeds in raw water treatment(Sumy State University, 2025) Hassan, A.B.; Hasan, M.B.; Shadhar, M.H.; Al-Kanany N., B.H.H.Adverse health and environmental impacts of conventional chemical compounds in treating water and wastewater encouraged the study of natural alternatives, especially plant-based compounds. This study aims to investigate the feasibility of Moringa oleifera (MO) seeds as an eco-friendly natural coagulant and to compare their effectiveness with the chemical coagulant – aluminum sulfate (Alum). The performance of MO in turbidity and chemical oxygen demand (COD) removal from raw water employing the jar test was examined. Coagulation conditions were optimized using a jar test to determine the optimum dose of MO and pH level. The impact of the MO on treated water characteristics (electrical conductivity, pH, and total dissolved solids) was also examined. The experiment used a range of MO doses (50, 100, 150, 200, and 300 mg/l) and Alum (5, 10, 20, 30, and 40 mg/l) to treat raw water samples. The performance of both coagulants followed similar trends. The maximum turbidity removal efficiency was about 97 % obtained at an optimum dosage of 100 mg/l of MO, while for COD, the highest removal was about 49 % at 150 mg/l of MO. No significant effect of MO dosing on the pH level of the solution was noticed, while a substantial increase in electrical conductivity from 591 ± 1.5 μS/cm to 620 ± 1.5 μS/cm was observed when the dosage of MO increased to 300 mg/l. Total dissolved solids (TDS) also increased for raw water from 255 ± 1.0 μS/cm to 367 ± 2.0 μS/cm at a 300 mg/l dosage. One-way analysis of variance for the relation between dose and turbidity removal shows that the model is significant (F-value of 76.1, P-value less than 0.0001).Item Plasticity of workpieces processed by deforming broaching with through deformations(Sumy State University, 2025) Nemyrovsky, Y.B.; Shepelenko, I.V.; Otamanskyi, V.V.; Melnyk, O.L.; Vasyliv, T.I.One of the essential parameters of the parts quality processed by deforming broaching is the surface plasticity, which depends on many factors and the technological aspects of the process. To create opportunities for technological control of the resource of used plasticity, it is necessary to evaluate the effect of deforming broaching modes on the plasticity resource of the workpiece. This work modeled the stress-strain state of an axisymmetric workpiece made of plastic metal under deforming broaching. The creation of finite-element models of the process made it possible to study the change in the parameters of the stress-strain state of the machined workpiece on its inner and outer surfaces. When analyzing the peculiarities of the change in the stress-strain state in the deformation cell, two zones of local plastic deformation appeared at the beginning of the contact zone and its end. The change in the plasticity increment along the deformation cell during the deformation of a thick-walled part also had two sharp peaks corresponding to the junction of the contact zone with the non-contact zone. It was proven that the size of the local plastic deformation zone depends on the workpiece thickness. The stress state in the contact zone and non-contact zones, as well as the influence of deforming broaching modes and workpiece thickness on the parameters of the stress-strain state and the deformation history of a material particle on the outer and inner surfaces of the workpiece, were investigated. When studying the features of the workpiece deformation by a group of deforming elements, it was found that the accumulated deformation and the resource of the used plasticity on the inner surface depend on the total deformation and the number of deforming elements. A new deformation scheme with consistent use of the plasticity resource on the outer and inner surfaces of the workpiece was developed. This allowed for designing a deforming broach with a group arrangement of deforming elements. The developed design ensured minimal use of the plasticity resource on the inner and outer surfaces. The conditions for the fracture (micro-peeling) appearance at the inner surface were identified. The obtained regularities made it possible to control the quality parameters based on the resource of the used plasticity of the surface layer of the inner and outer surfaces of the part during its deforming broaching. These studies also made it possible to refine the technology for restoring worn piston pins, which includes deforming broaching and subsequent chemical and thermal treatment, the duration of which was reduced by 20 %. The introduction of this technology at one enterprise alone saved 4.5 tons of 12HN3A steel when restoring 1000 piston pins of 10D100 diesel engines.Item An innovative approach to non-contact cleaning of mini-ball bearings(Sumy State University, 2025) Kostyunik, R.; Mikosianchyk, O.; Stelmakh, A.; Kushchev, A.; Shymchuk, S.; Zaichuk, N.The bearing industry represents a critical segment of the modern economy, directly influencing the operational reliability and service life of various machines, equipment, and components employed in highresponsibility sectors of mechanical engineering and transportation infrastructure. Despite ongoing advancements and technological improvements in rolling bearing manufacturing, there remains a significant risk of residual contamination by particulates of various origins, primarily during production. This problem becomes particularly relevant in the case of miniature rolling bearings, characterized by an outer diameter of less than 30 mm. Conventional cleaning techniques currently applied in industrial practice often demonstrate limited efficiency in removing microcontaminants from hard-to-access zones within non-separable bearing assemblies. This study proposed an innovative non-contact cleaning method based on comprehensive investigations. The technique integrates the synergistic effects of pulsed alternating magnetic fields and ultrasonic excitation, offering enhanced cleaning performance without compromising the structural integrity of precision components. The results of the granulometric composition of the removed contaminant particles of ball bearings by different methods were presented. The optimum angles of bearing inclination were experimentally evaluated at various locations of ultrasonic wave radiation sources and the action of a pulsed magnetic field. The effectiveness of the developed combined method on aircraft ball bearings demonstrated its advantages in removing both large and small contaminants, confirmed by vibration diagnostics and microscopic analysis. Testing of the method at leading aircraft manufacturers underlines the practical significance of the developed approach and has the potential to significantly improve the quality, service life, and reliability of precision parts and mechanisms. Depending on the contamination degree and the bearing type, the cleaning time ranged from several seconds to 2–3 minutes, allowing the developed combined method to be integrated into the manufacturing technological cycle of rolling bearings using the necessary automated systems and equipment as the final cleaning operation. This ensures the principle of improving the innovation of production. Using ultrasonic waves allowed for the removal of the strongest films of complex structure. Overall, combining ultrasound with a pulsed magnetic turbulent cleaning method significantly increased the effectiveness of the cleaning process.Item HCNG for sustainable emission reduction in SI engines(Sumy State University, 2025) Baswana, C.S.; Narang, S.A.As the urgency for environmental protection and the need for alternative energy sources grow, the quest for substitutes for petroleum has become increasingly critical. Natural gas, mainly comprised of methane, is one of the finest alternative fuels with advantageous properties like a high hydrogen-to-carbon (H/C) ratio and octane number. Nevertheless, natural gas engines that operate on spark ignition (SI) encounter challenges, including slow combustion rates and restricted lean-burn capabilities, which lead to considerable variations from cycle to cycle, diminished power output, and higher fuel consumption. Consequently, it is vital to improve the combustion process under lean conditions. A viable approach to this issue is incorporating hydrogen, which is thought to mitigate these challenges. Blending of hydrogen increases the combustion rate and stability of natural gas, resulting in improved efficiency, shorter burn times, and a broader range of lean operation. This research examines the effects of adding various levels of hydrogen to compressed natural gas (CNG) in a 3-cylinder internal combustion engine (ICE). The performance, emissions, and combustion characteristics were analyzed at various equivalence ratios, utilizing brake torques, spark timing, and throttle conditions. The results demonstrated that increased hydrogen content improves brake thermal efficiency in lean conditions, achieving a peak brake thermal efficiency of 23 % at 2500 rpm with a blending of 5 % hydrogen, but declining with higher hydrogen concentrations. Significant enhancements in brake thermal efficiency were observed. Blending of hydrogen with CNG resulted in a reduction in releases of carbon monoxide (CO), hydrocarbons (HC), and carbon dioxide (CO2) compared to standard CNG. However, it was noted that nitrogen oxides (NOx) emissions increased for hydrogen-enriched compressed natural gas (HCNG) as compared to CNG.Item Experimental design approach to evaluating factors for enhanced cork mass insulation(Sumy State University, 2025) Kermezli, T.; Announ, M.; Ladeg, S.; Douani, M.This research examines the mechanical properties of cork, explicitly focusing on enhancing its mass insulation characteristics by calculating the apparent diffusion coefficient. This coefficient was obtained by combining conductimetric measurements with model calibration and further refined using an optimization model based on the Bat Algorithm. A series of eight experiments was conducted to examine the impact of operating parameters and their interactions on cork’s diffusion coefficient using the experimental design according to the response surface methodology. The factors considered included three potential growth areas spread over the North of Algeria, cutting directions, and material states (treated and native). Given the duration and expense of the experiments, a linear model incorporating interactions was employed to examine the effects of all parameters. The Minitab software allowed for estimating the model’s coefficients, including interactions, indicating that the diffusion coefficient remains unaffected by the planting area. However, the tangential cutting direction influences the mass insulation property. Additionally, the negative sign of the coefficient associated with thermal heat treatment indicates that this factor enhances cork’s insulation performance, reducing the diffusion coefficient from 3.40·10–12 m²/s to 4.57·10–13 m²/s. Moreover, treated cork exhibits a diffusion coefficient value four times lower than that resulting from the tangential cutting direction. As a result, the experimental findings enabled the development of a simplified predictive model for mass diffusivity, with a coefficient of determination of 0.90 and a significance level of 0.05.