Yazar "Pimenov, Danil Yurievich" seçeneğine göre listele

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    Determination of machinability metrics of AISI 5140 steel for gear manufacturing using different cooling/lubrication conditions
    (Elsevier, 2022) Usca, Usame Ali; Uzun, Mahir; Sap, Serhat; Giasin, Khaled; Pimenov, Danil Yurievich; Prakash, Chander
    AISI 5140 steel is mostly used in gear manufacturing for variety of industries. Those gears can be manufactured via casting, powder metallurgy or forging techniques. Nevertheless, machining (via turning and milling processes) remains the most common manufacturing method to fabricate them. Milling of gears made from 5140 steel can be challenging due to the excessive energy consumption, rapid tool wear and poor surface finish. Therefore, traditional and environmentally friendly coolants are usually applied during machining to improve the surface finish and prolong tool life. The current study aims to investigate machinability performance of 5140 steel under different cooling/lubrication conditions. Several machinability metrics were investigated and analyzed (surface roughness, cutting temperature, tool wear, chip morphology, and energy consumption). Milling tests were performed under different cutting speeds (75 and 100 m/min), different feed rates (0.15 and 0.2 mm/rev) and dry, minimum quantity lubrication (MQL), and cryogenic liquid cooling/lubrication conditions (dry, MQL and cryo-LN2). The results showed that using Cryo-LN2 cooling/lubrication tended to improve all the investigated machinability metrics compared to dry condition. The surface roughness was reduced by approximately 54%, while the cutting temperature was reduced by 87%. Similarity, the cutting tool flank wear was reduced by 20% thus energy consumption was minimized by 15%. The current study shows the importance of cryogenic machining in industry for difficult to cut materials. (C) 2022 The Authors. Published by Elsevier B.V.
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    Evaluation of Mechanical and Tribological Aspect of Self-Lubricating Cu-6Gr Composites Reinforced with SiC-WC Hybrid Particles
    (Mdpi, 2022) Usca, Usame Ali; Sap, Serhat; Uzun, Mahir; Giasin, Khaled; Pimenov, Danil Yurievich
    Because of their high thermal conductivity, good corrosion resistance, and great mechanical qualities, copper matrix composites are appealing materials utilized in a variety of industries. This study investigates the mechanical properties of copper-graphite (Cu-Gr) matrix composites reinforced with silicon carbide (SiC) and tungsten carbide (WC) particles by hot pressing using powder metallurgy method. The goal is to investigate the influence of the reinforcement ratio on the mechanical characteristics of copper composite materials generated (density, hardness, flexural strength, and wear resistance). SEM, EDS, and X-RD analysis were used to perform metallographic examinations. The highest relative density with a value of 98.558% was determined in the C3 sample. The findings revealed that when the reinforcement ratio was raised, the hardness rose. The highest hardness value was observed in the C6 sample with an increase of 12.52%. Sample C4 (with the lowest SiC and WC particles ratio) had the highest bending stress (233.18 MPa). Bending stress increased by 35.56% compared to the C1 sample. The lowest specific wear rates were found in the C4 sample, with a decrease of 82.57% compared to the C1 sample. The lowest wear rate (6.853 x 10(-7) mm(3)/Nm) also occurred in the C4 sample. The microstructural analysis showed that the hybrid reinforcement particles exhibited a homogeneous distribution in the copper matrix. X-RD analysis showed that there was no intermediate reaction between the parent matrix and the hybrid reinforcements. A good interfacial bond was observed between the matrix structure and the hybrid reinforcements. The motivation of this research was to utilise the advantages of the unique features of SiC-WC hybrid particles to improve the performance of newly developed Cu-6Gr composites for wear-resistance applications.
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    Investigation of the Effects of Cooling and Lubricating Strategies on Tribological Characteristics in Machining of Hybrid Composites
    (Mdpi, 2022) Sap, Serhat; Usca, Usame Ali; Uzun, Mahir; Kuntoglu, Mustafa; Salur, Emin; Pimenov, Danil Yurievich
    Engineering materials are expected to contain physical and mechanical properties to meet the requirements and to improve the functionality according to their application area. In this direction, hybrid composites stand as an excellent option to fulfill these requests thanks to their production procedure. Despite the powder metallurgy method that allows for manufacturing products with high accuracy, machining operations are still required to obtain a final product. On the other hand, such materials are characterized with uncertainties in the structure and extremely hard reinforcement particles that aggravate the machinability. One of the prominent solutions for better machinability of composites is to use evolutionary cooling and lubricating strategies. This study focuses on the determination of tribological behavior of Cu-based, B-Ti-SiCP reinforced, about 5% wt. hybrid composites under milling of several environments, such as dry, minimum quantity lubrication (MQL)-assisted and cryogenic LN2-assisted. Comprehensive evaluation was carried out by considering tool wear, temperature, energy, surface roughness, surface texture and chips morphology as the machinability characteristics. The findings of this experimental research showed that cryogenic cooling improves the tribological conditions by reducing the cutting temperatures, flank wear tendency and required cutting energy. On the other hand, MQL based lubricating strategy provided the best tool wear index and surface characteristics, i.e., surface roughness and surface topography, which is related to spectacular ability in developing the friction conditions in the deformation zones. Therefore, this paper offers a novel milling strategy for Cu-based hybrid composites with the help of environmentally-friendly techniques.
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    Skull Thickness Calculation Using Thermal Analysis and Finite Elements
    (Mdpi, 2021) Calisan, Mucahit; Talu, Muhammed Fatih; Pimenov, Danil Yurievich; Giasin, Khaled
    In this study, the skull bone thicknesses of 150 patients ranging in age from 0 to 72 years were calculated using a novel approach (thermal analysis), and thickness changes were analyzed. Unlike conventional thickness calculation approaches (Beam Propagation, Hildebrand), a novel heat transfer-based approach was developed. Firstly, solid 3D objects with different thicknesses were modeled, and thermal analyses were performed on these models. To better understand the heat transfer of 3D object models, finite element models (FEM) of the human head have been reported in the literature. The FEM can more accurately model the complex geometry of a 3D human head model. Then, thermal analysis was performed on human skulls using the same methods. Thus, the skull bone thicknesses at different ages and in different genders from region to region were determined. The skull model was transferred to ANSYS, and it was meshed using different mapping parameters. The heat transfer results were determined by applying different heat values to the inner and outer surfaces of the skull mesh structure. Thus, the average thicknesses of skull regions belonging to a certain age group were obtained. With this developed method, it was observed that the temperature value applied to the skull was proportional to the thickness value. The average thickness of skull bones for men (frontal: 7.8 mm; parietal: 9.6 mm; occipital: 10.1 mm; temporal: 6 mm) and women (frontal: 8.6 mm; parietal: 10.1 mm; occipital: 10 mm; temporal: 6 mm) are given. The difference (10%) between men and women appears to be statistically significant only for frontal bone thickness. Thanks to the developed method, bone thickness information at any desired point on the skull can be obtained numerically. Therefore, the proposed method can be used to help pre-operative planning of surgical procedures.
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    Tribological Aspects, Optimization and Analysis of Cu-B-CrC Composites Fabricated by Powder Metallurgy
    (Mdpi, 2021) Usca, usame Ali; Uzun, Mahir; Kuntoglu, Mustafa; Sap, Serhat; Giasin, Khaled; Pimenov, Danil Yurievich
    Tribological properties of engineering components are a key issue due to their effect on the operational performance factors such as wear, surface characteristics, service life and in situ behavior. Thus, for better component quality, process parameters have major importance, especially for metal matrix composites (MMCs), which are a special class of materials used in a wide range of engineering applications including but not limited to structural, automotive and aeronautics. This paper deals with the tribological behavior of Cu-B-CrC composites (Cu-main matrix, B-CrC-reinforcement by 0, 2.5, 5 and 7.5 wt.%). The tribological characteristics investigated in this study are the coefficient of friction, wear rate and weight loss. For this purpose, four levels of sliding distance (1000, 1500, 2000 and 2500 m) and four levels of applied load (10, 15, 20 and 25 N) were used. In addition, two levels of sliding velocity (1 and 1.5 m/s), two levels of sintering time (1 and 2 h) and two sintering temperatures (1000 and 1050 degrees C) were used. Taguchi's L-16 orthogonal array was used to statistically analyze the aforementioned input parameters and to determine their best levels which give the desired values for the analyzed tribological characteristics. The results were analyzed by statistical analysis, optimization and 3D surface plots. Accordingly, it was determined that the most effective factor for wear rate, weight loss and friction coefficients is the contribution rate. According to signal-to-noise ratios, optimum solutions can be sorted as: the highest levels of parameters except for applied load and reinforcement ratio (2500 m, 10 N, 1.5 m/s, 2 h, 1050 degrees C and 0 wt.%) for wear rate, certain levels of all parameters (1000 m, 10 N, 1.5 m/s, 2 h, 1050 degrees C and 2.5 wt.%) for weight loss and 1000 m, 15 N, 1 m/s, 1 h, 1000 degrees C and 0 wt.% for the coefficient of friction. The comprehensive analysis of findings has practical significance and provides valuable information for a composite material from the production phase to the actual working conditions.