Browsing by Author "Isametova M."

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    Determination of the rational number of blades of the centrifugal wheel of a submersible pump
    (2020-01-01) Isametova M.; Karaivanov D.; Nussipali R.
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    Development And Verification Of Mechanical Characteristics Of A Composite Material Made Of A Thermoplastic Matrix And Short Glass Fibers
    (2021-01-01) Isametova M.; Abilezova G.; Dishovsky N.; Velev P.
    The paper presents the results of computer modeling and prediction of the mechanical properties of composite materials with a polycarbonate matrix filled with short glass inclusions. At the micro-level, the influence of the volume of inclusions on the mechanical properties of the designed composite based on polycarbonate matrix is studied in the DIGIMAT (France) program. It was found that with a ratio of the sizes of inclusions in the range of 468÷60, the particles have a needle shape, and the material with such inclusions has a higher stress limit and elastic modulus than with a shape coefficient less than 50. The components of the fiber orientation tensor were also determined, at which the values of computer modeling are in good agreement with experimental data. The influence of the size of the finite element grid on the characteristics of the composite at the macro level was studied, and recommendations were given for choosing the size of the face of the finite element. The adequacy of computer models was confirmed by the results of field tests. The paper presents the results of testing flat samples made by injection molding technology. Mechanical tests were carried out for three variants of samples made of composite material based on a polycarbonate matrix with 10 %, 20 % and 30 % inclusions. The discrepancy between the experimental and computer results for samples with 10 %, 20 % content of short chopped fibers is explained by the influence of technological factors on the properties of the material at the macro-level. The conducted research allowed us to develop a computer modeling technique used at the stage of development of polymer composites based on thermoplastic matrices with short glass inclusions
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    PROPERTIES OF GLASS-FIBER REINFORCED POLYCARBONATES FOR CENTRIFUGAL PUMPS IMPELLERS
    (2022-01-01) Isametova M.; Dishovsky N.; Velev P.; Duisengali A.
    A significant number of properties of composites based on polycarbonates, unfilled and filled with 10 - 30 % short glass fibers of E-glass, treated with 3-(aminopropyl) triethoxy silane, were studied. The purpose of the study is to determine whether these composites can be used to manufacture impellers for centrifugal pumps. It was found that with increasing the amount of filler, the properties of polycarbonate composites change as follows: in general, the physico-mechanical parameters (all modules, tensile strength), stiffness and flexural strength increase, maximum deformation, as well as elastic and impact resistance decrease somewhat. The volume and surface resistivity decrease, the coefficient of thermal conductivity increases. The main reason for these changes in the properties of the composites is the good adhesion at the polymer matrix-fiber interphase which is attributed to the strong physical interaction due to silane used and as a result of the good wetting of the fibers from the polycarbonate matrix and improved compatibility. Based on the results obtained, it can be concluded that polycarbonate composites, filled with 10 - 30 % short glass fibers can be successfully used for the production of centrifugal pumps impellers, as they meet a significant number of requirements for materials with such application.
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    The selection of optimal reversible two-speed planetary gear trains for machine tool gearboxes
    (2020-01-01) Troha S.; Vrcan Ž.; Karaivanov D.; Isametova M.
    The application of multi-criteria optimization to two-carrier two-speed planetary gear trains is outlined in this paper. In order to determine the mathematical model of multi-criteria optimization variables, the objective functions and conditions must be determined first. Two-carrier two-speed planetary gear trains with brakes on coupled shafts are analyzed in this paper. The mathematical model covers the determination of the set of the Pareto optimal solutions as well as the method for selecting an optimal solution from this set. A numerical example is provided to illustrate the procedure in which the optimal two-speed planetary gear train is selected and defined by design parameters.