HERALD of the Donbass State Engineering Academy

Electroslag billets casting using electrically conductive exothermic fluxes

2021-07-13T11:03:15+00:00

Vlasov A. F., Makarenko N. O., Kushchiy A. M., Golub D. M. Electroslag billets casting using electrically conductive exothermic fluxes // Herald of the DSEA. – 2019. – № 2 (46). – P. 5–10.
The method of manufacturing billet sectors of the coilers of 20C3MVF (20Х3МВФ) steel using the “solid” start and exothermic fluxes, which significantly reduces the laboriousness of their manufacture, and the molded billet sectors of the coilers of the coilers, obtained by the ESR method, have a smooth surface without corrugations, sinkers, slag inclusions, heat treatment provides the required mechanical properties in cast electroslag metal within the grade composition of this steel and is higher than that of the forged metal of open smelting. A mechanical mixture of aluminum powder and industrial scale was considered as the basis for the exothermic mixture. The effectiveness of electroslag casting in the manufacture of cast billets by using an exothermic flux (scale, ferroalloys and aluminum powder) in quantities sufficient for exothermic reactions to be carried out was confirmed; ECL ensures the production of high-quality castings with minimal allowances for machining. The quality of cast electroslag steel 20H3MVF was studied using a “solid” start, its gas, chemical composition and microstructure were analyzed, and the quality was consistent with forged steel of open smelting. The expediency of using a “solid” start with the use of an exothermic flux in the initial period of targeting a slag bath of the required volume at ECL was studied, while the electroslag castings of the winder drum blanks are characterized by a defect-free surface with a yield of up to 85%, a stable cross-section chemical composition, low content of gases and non-metallic inclusions. The structure of steel 20H3MVF, related in its chemical composition to the martensitic-ferritic grade steel, was studied both in the cast metal of the ESR and in the forged metal of the induction melting.

Influence of heat treatment on the mechanical properties of surfaced metal in die-casting steels

2021-07-13T11:03:12+00:00

Holub D. M., Kushchii H. M., Haivoronskyi O. O. Influence of heat treatment on the mechanical properties of surfaced metal in die-casting steels // Herald of the DSEA. – 2019. – № 2 (46). – Р. 11–16.

It is technically promising and economically feasible by increasing the lifetime of the tool and reducing the cost of the die tool to make it surfaced. In this case, the regulation of the properties of the surfaced layer is most accessible by changing the composition of the surfaced metal and its thermal treatment modes. Rebuilding worn parts of the parts significantly reduces the consumption of metal for the manufacture of spare parts and a new tool. The surfaced layer can be applied on the basis of structural steel, which achieves economy of scarce alloyed steels. The most widespread use was given to the melting of the die tool with coated electrodes. To increase the durability of the stamping tool for cold stamping, the alloying of steels with active carbide-forming elements of tungsten and vanadium, forming solid carbides, is significantly affected. The hardness of the steel during the release is inversely proportional to the content of carbides in it, so the steel Х2В2ФМ and 8Х4ГСВ4Ф are the best in the carbide content. The steels of type X12 with high carbide content have a significant carbide heterogeneity. The residual austenite in steels compensates, within certain limits, an increase in the volume that is produced by the formation of martensite and in this it manifests its positive effect. However, residual austenite as a result of the transformations reduces the strength of steels under stresses depending on the tempering temperature at tempering from the optimum temperatures. The highest hardness is U8 steel, which obtains high hardness (more than 65 HRC) when quenched at a temperature of 750 °C. Complexly alloyed steels Х2В2ФМ, 8Х4ГСВ4Ф, 7Х3ГСМ and 7ХГ2ВФМ obtain the maximum hardness at tempering at 900 °С. Application of steel 8Х4ГСВ4Ф for surfacing of a stamping tool, performing separate operations, is the most optimal and will allow to significantly increase the life of stamps during their repeated use for surfacing.

Gas-air heater for heating rotation parts during welding and surfacing

2021-07-13T11:03:08+00:00

Kassov V. D., Kabatsky A. V., Berezhnaya E. V., Malygina S. V. Gas-air heater for heating rotation parts during welding and surfacing // Herald of the DSEA. – 2019. – № 2 (46). – P. 17–21.

One of the important stages of the technology for surfacing massive oversized parts is their heating to the required temperature. Moreover, the inability to maintain the accepted heating parameters inevitably leads to the formation of defects in the deposited layer (cracks, delamination, etc.). The aim of the work was to improve equipment for stable and safe maintenance of the process of heating parts during welding and surfacing. The design of a gas-air heater for welding is proposed. At the same time, the inner sheet of the heater is heated by the gas-air flame of the burners, the component radiated by heat from it. Hot gases, combustion products are diverted to a safe place. Calculation of heater burners is based on their heat output. Given the inevitable heat loss during surfacing, as well as for structural reasons, three burners with a capacity of 55,000 kcal / h are installed in the heater. A check calculation of the burners was also carried out. A calculation was made for the absence of a flamethrough, which showed the safety of their use. The size of the burner outlet nozzle was also calculated. Based on the recommendations, it was found that the nozzle diameter should be 2.3 mm. The heater consists of two split halves (front and rear), which are cavities inside which burners are installed. Two burners are located in the rear half of the heater, and one in the front half. Both halves freely translationally move in the direction of the longitudinal axial line of the installation, which is convenient when installing the part for surfacing, as well as when removing it. Above and below, the halves of the heater close, forming gaps for the convenience of surfacing and moving the welding head at the top, and cleaning the flux peel and flux below. Since the torches are located in the enclosed space of the heater, the ingress of hot gases (combustion products) onto the welding head is eliminated, and the working conditions of the weld beads are improved and the quality of the metal is improved. The heater operates at high temperatures, so it is made of stainless heat-resistant sheet steel with a thickness of 4 mm. As tests have shown, the selected design of the heater allows to ensure stability and safety of the process of heating parts during welding and surfacing, significantly reduce heat loss and perform surfacing without interruptions. The use of a heater can be recommended for welding and surfacing of rotation parts in production conditions.

The effect of plastic creep deformations of the interlayer during the TLP-bonding of high-temperature alloys on the formation of the stress-strain state of the nodes in the cooling process

2021-07-13T11:03:06+00:00

Matvienko M. V., Kvasnitsky V. V., Holub D. M. The effect of plastic creep deformations of the interlayer during the TLP-bonding of high-temperature alloys on the formation of the stress-strain state of the nodes in the cooling process // Herald of the DSEA. – 2019. – № 2 (46). – P. 22–28.

During thermal loading, accelerated cooling of nodes with a soft interlayer in a small area located near the interlayer at the butt edge and in the interlayer itself creates a complex SSS due to the difference between the CLTE of the metal to be joined and the interlayer. The method of computer simulation was used to study the formation of the stress-strain state of the nodes during the TLP-bonding of a heat-resistant alloy in the process of accelerated cooling, followed by exposure at a creep temperature. It was established that accelerated cooling with subsequent exposure for 540 s reduces stresses in the interlayer and in a small zone of the base metal near its edge due to short-term deformations and creep in the interlayer. At the same time, the degree of creep resistance of the interlayer compared to the base metal within the accepted limits (0.85 or 0.7) practically does not play a role. The resulting creep deformations have little effect on the nature of the stress field. Short-term plastic deformations in the variants with a smaller CLTE difference between the interlayer and the base metal and, accordingly, with a lower stress level, are small, they occur only in a small portion of the interlayer at the joint edge. At the same time, they are noticeably reduced compared with fast cooling as a result of stress reduction due to creep. In variants with a larger CLTE difference and, consequently, a higher level of stresses, short-term plastic deformations markedly increase and are distributed along the entire length of the interlayer. Compared with fast cooling, they are reduced slightly. Creep deformations with slow cooling followed by exposure appear and significantly exceed the level of short-term deformations in the variants with a small difference between the CLTE of the interlayer and the base metal. They change little when the creep resistance of the interlayer varies within accepted limits. The stiffness coefficients of the stress state, and accordingly, the degree of hardening and softening of the metal in the joint zone, with slow cooling, both in the base metal and in the interlayer, change slightly, mainly in small areas near the edge of the joint.

The effect of the yield strength of the interlayer on the stress-strain state of the nodes during diffusion welding and brazing of a heat-resistant alloy, taking into account the plastic deformations of materials during rapid cooling

2021-07-13T11:03:03+00:00

Matvienko M. V., Kvasnitsky V. F., Makarenko N. O. The effect of the yield strength of the interlayer on the stress-strain state of the nodes during diffusion welding and brazing of a heat-resistant alloy, taking into account the plastic deformations of materials during rapid cooling // Herald of the DSEA. – 2019. – № 2 (46). – Р. 29–34.

In this work, using computer simulation, the stress-strain state (SSS) under the action of thermal load of cylindrical samples with soft layers that have a lower yield strength than the base metal was investigated. It has been established that in a small zone of the base metal near the outer surface at the junction with the interlayer and in the interlayer itself there arises a complex SSS with radial, axial, circumferential and tangential stresses. Volumetric SSS due to the difference between the CLTE of the interlayer and the base metal is created only in the interlayer along its entire length and in small areas with a length of no more than 10 interlayer thickness, in the base metal near the outer edge of the interlayer. Depending on the degree of “softness” of the interlayer, the stress level changes. The change in the yield strength of the interlayer within 0.75 ... 0.85 of the yield strength of the base metal has little effect on the distribution pattern and magnitude of the stresses in the zone of the volumetric SSS, only the length of this zone changes, which is about 5 thicknesses of the interlayer. The appearance of plastic de-formations in the interlayer has little effect on the stiffness coefficient of the stress state and the degree of hardening or softening of both the base metal and the interlayer material. At the joint edge, the metal is strengthened somewhat more than in the elastic problem. The softening of the metal in the middle part of the joint when the temperature changes (thermal cycling) should favorably influence the formation of a joint in the zone of deformation stagnation during diffusion welding. The temperature change (thermal cycling) contributes to the formation of a joint in the zone of deformation stagnation during diffusion welding. The change in the value of the yield strength and CLTE of the layer in the accepted limits practically do not play a role. The softening of the base metal in the middle part of the joint and the interlayer near its edge must be taken into account when designing such assemblies and choosing the properties of the interlayer material.

Improving the efficiency of electric arc surfacing in a longitudinal magnetic field

2021-07-13T11:03:01+00:00

Razmyshlyaev A. D., Ahieieva M. V. Improving the efficiency of electric arc surfacing in a longitudinal magnetic field // Herald of the DSEA. – 2019. – № 2 (46). – P. 35–40.

To improve the efficiency of the submerged arc welding process, the use of external longitudinal magnetic fields (LMF) is promising. In this case, the coefficient of melting of the electrode wire increases, the depth and area of the base metal melted decreases, the share of the base metal in the weld metal decreases. The coefficient of melting of the electrode wire (α_р) during arc surfacing and submerged-arc welding in a LMF with reverse and direct polarity is determined by ferromagnetic and paramagnetic (nonmagnetic) wires. The increase in the coefficient of melting of the electrode wire occurs when exposed to a constant LMF, and also to a lesser extent at LMF with a frequency of 50 Hz when surfacing by ferromagnetic wire on products made of ferromagnetic and nonmagnetic steels. The maximum increase in the melting ratio of the wire occurs during welding and welding with a constant magnetic field. The effect of influence decreases with an increase in the frequency of LMF to 4 - 6 Hz and practically does not change with a further increase in the frequency of the field to 50 Hz. It is shown that the effect of increasing the melting coefficient of the electrode wire depends on its magnetic properties. When surfacing from non-magnetic materials, there is no increase in the melting coefficient. During surfacing by a consumable electrode, the trends in the influence of the LMF on the distribution pattern of the gas-dynamic pressure of the arc along the radius established for the process of welding with a tungsten electrode in argon remain. It is established that when surfacing in a constant and frequency of 50 Hz longitudinal magnetic field, the penetration depth of the base metal decreases if the value of the longitudinal induction component exceeds 65 mT. Constant and variable LMF has an inhibitory effect on the flow rate of liquid metal in the bath, which leads to a decrease in the efficiency of penetration of the base metal during surfacing.

Thermodynamic studies of CuO-Fe2O3-Al exotermic mixture with a combine oxidant in self-shielding flux cored wires

2021-07-13T11:02:59+00:00

Trembach B. A., Grin A. G., Miloserdov P. A., Trembach I. A. Thermodynamic studies of CuO-Fe₂O₃-Al exotermic mixture with a combine oxidant in self-shielding flux cored wires // Herald of the DSEA. – 2019. – № 2 (46). – P. 41–46.

An upcoming trend in the development of self-shielding flux cored wires is the development of surfacing materials with exothermic mixtures, in order to increase melting parameters. However, the introduction of a significant amount of exothermic mixture may be undesirable in obtaining the desired composition of the deposited metal, due to the reduction of the components of the oxidizer and its subsequent pass into the deposited metal. Use the exothermic mixture with the combined oxidizer of the CuO-Fe₂O₃-Al system as the components of the exothermic mixture of the stock of the flux cored wire, which makes it possible to control the deposited metal composition to a greater degree. Computer-aided calculation of the adiabatic combustion temperature of the combined exothermic mixture under investigation was carried out using the ISMAN-THERMO program. Studies have shown that an increase of graphite content (from 6 % to 9 %) in the flux cored wire leads to a significant decrease of the adiabatic temperature of combustion of an exothermic mixture with a combined oxidizer, which is caused by an activation of stock melting. It was determined that the introduction of graphite reduces the adiabatic temperature of combustion and can eliminate the possibility of copper boiling, as evidenced by the decrease in the content of the latter in the gas phase. For a composition with a smaller amount of graphite (6 % C), carbon passes into the metal phase, only in the form of carbides. With a larger amount of graphite (9 % C) in the composition of the stock, it is possible to provide passing of free carbon into the melting zone. Thermodynamic calculations of a complex multicomponent exothermic mixture, CuO-Fe₂O₃-Al, with a combined oxidizer of the system have shown that an increase of CuO content leads to an increase in the metal phase and a decrease in the oxide phase, for the cases under consideration.

New directions in thermodynamic research of high-entropy alloys

2021-07-13T11:02:56+00:00

Turchanin M. A., Dreval L. A., Agraval P. G., Dovbenko A. I., Ilyenko S. M. New directions in thermodynamic research of high-entropy alloys // Herald of the DSEA. – 2019. – № 2 (46). – Р. 47–50.

A thermodynamic study of high-entropy alloys (HEA) of the Co–Cr–Cu–Fe–Ni system was performed. For this purpose, we used our own self-consistent base of thermodynamic parameters of the phases of ten two-component and ten three-component systems that are part of the studied system. Using this database and the CALPHAD method, the following were performed: the thermodynamic properties of four- and five-component equiatomic melts of the Co–Cr–Cu–Fe–Ni system were calculated at temperatures 1873 K and 1500 K; the phase transformations in a five-component system were modeled. The excess integral functions of mixing of four-component systems with copper and the Co–Cr–Cu–Fe–Ni system demonstrate positive deviations from ideality, which is due to positive copper–chromium pair interactions in the Co–Cr–Cu, Cr–Cu–Ni, Cr–Cu–Fe systems, copper–iron in the Cr–Cu–Fe, Co–Cu–Fe, Cu–Fe–Ni systems, copper–cobalt in the Co–Cr–Cu, Co–Cu–Fe systems. The behavior of the components in the Co–Cr–Fe–Ni system is close to ideal. A comparison of the values of thermodynamic functions calculated at 1873 K and 1500 K showed that a positive deviation from ideality of the excess thermodynamic mixing functions increased slightly with decreasing temperature and the magnitude of the ideal contribution to the Gibbs energy noticeably decreases. The results of modeling phase transformations demonstrate their similarity in four-component systems with copper and in the Co–Cr–Cu–Fe–Ni system. In four systems with copper (Co–Cr–Cu–Fe, Co–Cr–Cu–Ni, Co–Cu–Fe–Ni, Cr–Cu–Fe–Ni), the FCC solution separeted into FCC2 rich in copper, and FCC1 with a high content of chromium, cobalt, iron and nickel, and in the Co–Cr–Fe–Ni system, there is a high mutual solubility of the components. According to our calculations, the equiatomic Co–Cr–Cu–Fe–Ni alloy is two phase with the FCC+BCC structure. Practical recommendations have been developed on the choice of compositions of precipitation hardened HEA.

Forming hollow parts by combined extrusion methods

2021-07-13T11:02:53+00:00

Aliieva L. I., Abhari P. B., Malii K. V., Samoglyadov A. D., Shimko A. I. Forming hollow parts by combined extrusion methods // Herald of the DSEA. – 2019. – № 2 (46). – P. 51–58.

The main methods of combined extrusion with hollow cylindrical and conical parts from the initial solid billets are considered. Combined extrusion in cups with flange is located at the bottom, should use a scheme such as combining radial and backward extrusion methods. To assess the deformed condition of parts, methods of dividing grids and microstructural analysis are considered. The investigation results are in qualitative agreement with finite element analyses. It is determined that the process occurs with acceptable uneven deformation with the section of the part and provides an acceptable investigation of the structure and hardening throughout the volume of the part. Consistent radial-forward extrusion - a method of obtaining parts such as deep sleeves and cups from the original solid billet. The proposed method with experimental investigation are showed that to make manufacturing complex profiled hollow parts with a variable wall thickness and a stepped cavity or outer surface. Extrusion methods to make parts such as cup with a thick bottom, according to which, in order to reduce the unevenness of deformation along the section of the part, metal in the bottom zone of the cup is subjected to alternating deformation by forward extrusion in branches and return radial extrusion into the bottom zone. Finite element simulation in extrusion process to make hollow conical part by software program as Deform-2D is considered. Change in the kinematics of the hollow conical part and the strain intensity distribution, confirming the general characters in the distribution of deformations with hollow parts such as cups with a blind hole are determined.

Features of the main technological and design parameters of the stationary stand-up stand for providing a non-forced cold pipe reduction process

2021-07-13T11:02:51+00:00

Korol R. M. Features of the main technological and design parameters of the stationary stand-up stand for providing a non-forced cold pipe reduction process // Herald of the DSEA. – 2019. – № 2 (46). – P. 59–63.

The method of cold pipe reduction on HPP mills is used in the manufacture of pipes with particularly high accuracy in wall thickness, outer and inner diameters, as well as in the manufacture of particularly thick-walled pipes using the “joint” method. The drawbacks of the working stands of the KPTR mill include the fact that the stroke length of the movable separator, in which the part blank is deformed, is less than the stroke length of the working stand, as well as the moving parts of the stand, are heavy, which, in turn, limits the rolling speed, reducing the very productivity of the mill. The movable cage of the working cage has low rigidity, which causes a significant amount of elastic deformation of the “working tool - rolling cage” system. This is confirmed by the calculations given in the work. Using the stationary stand of the KPTR mill with supporting rollers to reduce particularly thin-walled pipes at the initial moment of rolling the front end of the pipe can lead to its constant flattening due to the large weight of the supporting rollers and working rollers, thus violating the stability of the rolling process. The disadvantages of the cage should be attributed, and the complexity of manufacturing support rollers. The aim of the work is to determine the technological and structural features of the stationary stand of the KPTR mill to ensure a non-forced cold pipe reduction process. To ensure the above, it was proposed to eliminate support rollers from the stand design and ensure free rolling of the rollers on the working cone, to carry out the so-called non-forced rolling process - as the separator moves, the rollers are rotated by friction forces in the deformation zone, and their trunnions freely roll over the calibrated working surface support bars. The use of a stationary stand of the KPTR mill with a roller with rolling elements makes it possible to achieve stability of the rolling process during cold reduction of thin-walled tubes, and in the manufacture of single-walled tubes using the “joint” method, ensure high surface quality and long-term durability of the working tool due to non-forced rolling process.

Features of the main technological and design parameters of the stationary stand of the KhPTR mill for rolling precision heat-exchange tubes

2021-07-13T11:02:14+00:00

Kravchenko O. V. Features of the main technological and design parameters of the stationary stand of the KhPTR mill for rolling precision heat-exchange tubes // Herald of the DSEA. – 2019. – № 2 (46).– P. 64–67.

Nowadays, the KPTR type mills of the design of the former VNIIMETMASH are widely spread. The advantages of these mills are the small size and simplicity of the working tool, which determines the overall relatively small weight of the cage and its large technological capabilities in the production of pipes. At the pipe factories of the former USSR, these mills are the main ones in the production of precision heat-exchange tubes, including those for fuel rod housings made of zirconium, nickel and titanium alloys, tubes for heat-absorbing assemblies, etc. Studies show that the performance of KhPTR camps is not limited by force parameters and metal ductility, but is mainly hampered by allowable reductions in the instantaneous deformation zone from the point of view of ensuring the required surface quality and the accuracy of the geometric dimensions of the pipes and the capabilities of the rotary mechanism with the Maltese cross. The relatively low productivity of the operating CPP mills is largely due to the small length of the crimping zone, which is associated with the kinematics of the cage, according to which the separator stroke amounts to about 60% of the stroke length of the stand cage driven by a crank mechanism. The purpose of the article is to determine the main features of the stationary stand design of the KPTR mill for rolling precision heat exchanging tubes, in which the course of the separator with working rollers would be equal to the course of the yoke. Using the stationary stand of the CPR mill allows, without a significant change in the mill design, not only increase the accuracy and quality of the pipe surface, but also multiply the mill performance by maximally leveling the elastic deformation of the “working roller - stand body” system when using a fixed thick-walled cage as the stand body, increasing the separator stroke by 1.7 times, as well as reducing the weight of the moving parts of the stand by more than 2 times.

Constructive features for the warmth rotating forging of precision pipe from alloys on the basis of the molybdenum

2021-07-13T11:02:13+00:00

Myronenko A. Yu. Constructive features for the warmth rotating forging of precision pipe from alloys on the basis of the molybdenum // Herald of the DSEA. – 2019. – № 2 (46). – P. 68–70.

Precision tubes made of molybdenum alloys are mainly used in special purpose equipment related to rocket technology and nuclear power. In this case, the limiting deviations of the individual types of specified pipes by the inside diameter should not exceed 0.01 mm, with the admission field in one side – 0,01 mm. It should be noted that alloys based on molybdenum may be subjected to plastic deformation only at elevated temperatures, at the same time they are characterized by a tendency to gas saturation during heat treatment. Based on the technical characteristics of the current state of the HTTP pipes of an external diameter of less than 6 mm, and especially of alloys based on molybdenum, are manufactured by drawing method, both on the mandrel and without it. However, getting these pipes from molybdenum-based alloys is impossible due to the fact that in order to provide a deformation process, it is necessary to heat both a deformable tube and a working tool up to 450-500˚С. At such temperatures, the strength of the rod holding the mandrel becomes low, and dragging will be accompanied by permanent breakdowns. Drawing on a movable (long) mandrel also does not provide the required precision of the finished pipes due to the fact that when removing the tube from the mandrel, the first is subject to multiple turning on the cutting machine, with the cross-section of the tube is ubiquitous. The purpose of the proposed article is to choose a method for the production of precision tubes made of molybdenum alloys, including those with profile holes (not rounded), as well as the design features of the deformation equipment. The most rational way of manufacturing precision pipes with an external diameter of less than 6 mm, including pipes with a profile (not round) hole, from alloys based on molybdenum is their warm radial wringing using rotational forging machines. To do this, it is possible to use existing rotary-forging machines in view of their modernization: the establishment of the mechanism of feeding the billet, as well as gas vodka for heating the part blank and forging dies.

The static friction torque while high pressure torsion determining

2021-07-13T11:02:49+00:00

Kvashnin V. O., Babash A. V., Yakovlev A. N. The static friction torque while high pressure torsion determining // Herald of the DSEA. – 2019. – № 2 (46). – C. 71–76.

The current technology of the use of rock metals for the manufactured parts is given. High pressure technology with high torsion torsion is described. We believe that research studies have been conducted to establish samples with simultaneous rotation. The research facility involves a 10 ton press. The incremental encoder Siemens 6FX2001-2DB02 was used very quickly. An asynchronous motion was made to represent the cruise in motion, which was subjected to a long-lasting Altivar 31. The reducer 2Ч-80 is required to obtain the necessary inspection and reliable motorcycle. When pressing with simultaneous rotation of the sample friction force occurs. You distinguish yourself by the power and the moment of static resistance of the expanding enterprise. Analytical realized forces and moments of stationary support of the enterprise were presented in the article. According to our information, the statistics of the supporting business, which were developed at the statistical moment with asynchronous electricity production with a maximum force at the previous level of 10 t, were presented and presented. The test indicator showed that the existing asynchronous electric motor of the experimental setup seems to withstand the statistics for testing in the friction mode at the previous disappearance with its simultaneous rotation. All trusted forces and moments of friction at the preliminary opening with simultaneous rotation, which is done for the titanium rock, which is the main worker in the production of various details of medical and necessary.

Studying the effect of magnetic treatment modes on changes in hardness and heat capacity of fast-cutting steels after treatment by a pulsed magnetic ield

2021-07-13T11:02:47+00:00

Kindenko N. I. Studying the effect of magnetic treatment modes on changes in hardness and heat capacity of fast-cutting steels after treatment by a pulsed magnetic ield // Herald of the DSEA. – 2019. – № 2 (46). – P. 77–82.

The present work is devoted to the study of issues related to improving the operational properties of tools from high-speed steels by means of magnetic-pulse processing. The analysis of the effect of magnetic treatment on the change in hardness and heat capacity of high-speed steels after treatment with a pulsed magnetic field is carried out. It is shown that the effectiveness of the magnetic treatment method depends on a number of factors relating both to the conditions of exposure to a tool by a magnetic field, and to the conditions in which this tool is operated. It was established that as a result of the impact of a pulsed magnetic field, the physicomechanical properties of high-speed steels change, the cold and hot hardness increases, and the tool material becomes more uniform in structure. It is noted that the primary cause of improving the performance of a tool subjected to magnetic treatment is the change in the properties of the tool material, which occurs due to the magnetostriction hardening of high-speed steel. It is shown that for a stable manifestation of the effect of magnetic treatment of an instrument, it is necessary in each specific case to take into account the value of the magnetic field strength, the dwell time of the instrument in the working inductor, and the aging time of the instrument after magnetic treatment. It has been established that an increase in tool life is not due to deficiencies in heat treatment, manifested in an increase in cold hardness, but due to an improvement in the properties of the tool material and, above all, such operational properties as hardness and heat resistance.

Analysis of hypothesis about the reasons of the calling upgrades of the durability of the tool from fast-cutting steel as a result of the exposure of the magnetic field

2021-07-13T11:02:44+00:00

Kindenko N. I. Analysis of hypothesis about the reasons of the calling upgrades of the durability of the tool from fast-cutting steel as a result of the exposure of the magnetic field // Herald of the DSEA. – 2019. – № 2 (46). – P. 83–88.

The present work is devoted to the analysis of hypotheses about the causes of the increase in durability of an instrument made from high-speed steels as a result of a magnetic field. It is shown that a prerequisite for increasing the durability of the cutting tool is the presence in the cutting zone of a magnetic field of various strengths or processing with a tool that has been previously hardened with a magnetic field. The established relationship between the wear resistance and the operational reliability of the axial tool, on the one hand, and the main quality characteristics, on the other hand, shows that the technology of processing parts with a magnetically machined tool can significantly increase the service life of the tool and the operational reliability of parts. It is noted that magnetic pulse treatment is a combination of electromagnetic and thermodynamic methods of controlling the non-equilibrium structure of a substance. It is shown that the effectiveness of the magnetic treatment method depends on a number of factors. It is noted that the primary cause of improving the performance of a tool subjected to magnetic treatment is a change in the properties of the tool material, which occurs due to the magnetostriction hardening of high-speed steel. It has been established that in order to sustain the magnetic effect of the tool and increase the tool life of high-speed steel when applying a magnetic field to the cutting zone, it is necessary to take into account the value of the magnetic field strength, the direction of the magnetic flux and the cutting conditions in each case.

Determining the quality of the manufacturing process of products with a given linear size

2021-07-13T11:02:42+00:00

Lamnauer N. Y. Determining the quality of the manufacturing process of products with a given linear size // Herald of the DSEA. – 2019. – № 2 (46). – Р. 89–92.

An important component in ensuring product quality is the evaluation of the quality of its manufacturing technology. The quality of the technology is evaluated by the quality of the products received. One of the indicators of the quality of engineering products is the linear size of the parts. Any product can be produced using various technologies, but each of them provides not the same quality. High quality is accompanied by increased costs, which in a competitive market is not always acceptable for manufacturers. Depending on the needs of the manufacturer regarding quality, it becomes necessary to identify a technology that provides the desired quality. The issues of creating a tool for assessing the quality of manufacturing parts by the accuracy of size to determine the gradation of the quality of technology are considered. It is proposed to introduce assessment of technology with intervals of quality. The research used the theoretical apparatus of probability theory and mathematical statistics. The use of a general model of the distribution of the linear dimensions of parts and the found estimates of its parameters is proposed. It is shown that the proposed model has three different forms of distribution density, as well as the dependence of the average size on the half-sum of the upper and lower values of their estimates. These forms can identify the quality of technology as high, medium, and low. Using the obtained results makes it possible to analyze the quality of the manufacturing process of products with a change in their processing volume. The technique of determining the quality level of the technological process as high, medium and low is presented. The results obtained allow us to find an assessment of the feasibility of the number of products with the desired quality.The conducted studies help in resolving issues of quality management of engineering products.

Features of the formation defects the ore-grab loading crane TAKRAF

2021-07-13T11:02:39+00:00

Gavrish Р. A., Ermakova S. A. Features of the formation defects the ore-grab loading crane TAKRAF // Herald of the DSEA. – 2019. – № 2 (46). – Р. 93–96.

The purpose of work is the analysis of the reasons formation of the defects metal construction of the loading crane. In work the specialized technique of the analysis of constructive realization of welded clusters is used. Namely: the analysis of the factors of influence caused by welding process, the analysis of loadings of welded knot and existence of transfer of power loadings in knot and also the analysis circuit packing solutions of welded knot of a metal construction. The three-dimensional model of section of the main beam in the SolidWorks program is created and sizes of deformations of the main beam when moving the cart are determined by rails. Creation of mathematical model of the deformation section the main beam. Determination of sizes deformations of a zone fastening internal and external pockets. The dependence sizes of the deformations on distance to an axis and subcart rail is established. Factors to on emergence the fatigue damages of a metal construction are defined. The analysis of the reasons emergence of the fatigue damages on the main beams of the crane is made. The type of the loading main beams of the crane is defined. Lines of influence of single force at the mobile loads of the main beams of the ore and clamshell loading crane are built. The analysis of the reasons of defects established at expert inspection of the ore and clamshell loading crane is made. The main directions of constructive changes of welded knot of the main beam for increase in a fatigue resistance of a metal construction of the crane are defined.

The influence of aggregation of the speed of the sleeve conveyor and the combine on the outlet of lava

2021-07-13T11:02:10+00:00

Stadnik M. I., Semenchenko A. K., Belitsky P. V., Semenchenko D. A. The influence of aggregation of the speed of the sleeve conveyor and the combine on the outlet of lava // Herald of the DSEA. – 2019. – № 2 (46). – Р. 97–102.

The intensification of processes, which is inherent in modern mining systems, involves increasing the load on technological, transport and auxiliary equipment of coal enterprises. Freight traffic on mine transport has a high unevenness, which significantly increases the amount of specific energy consumption for cargo transportation. The reason for the uneven cargo flow from the lava is the uneven feed rate of the combine during the technological cycle of its operation. Adjustment of the original cargo flow from the bench by adjusting the speed of the downhole conveyor under favorable conditions allows to minimize the required amount of technological capacity of the silo hopper, its mass, to fit its dimensions in the dimensions of the cross-section of the gutter. Therefore, the question of determining the possibility of regulating the speed of transportation of minerals by a conveyor belt is urgent and can greatly simplify the solution of the problem of introduction of a controlled drive on machinery and equipment of inland transport of a mining enterprise. Therefore, the purpose of this work is to determine the analytical method using the results of experimental studies of the influence of the method of regulating the speed of the lava conveyor on the non-uniformity of the original cargo flow from the lava. In order to achieve this goal, a mathematical model of the process of formation of the original cargo flow from a bench equipped with a cleaning combine and a bench scraper conveyor with an adjustable drive was developed, which takes into account the parameters of the technological cycle of the combine work, the speed and direction of movement of the combine, speed. Experimentally established: the coefficient of unevenness of the original cargo flow from the lava is greater than the value recommended by the conventional method of calculating the means of transport of coal from complex mechanized lava. Established analytically: the largest reduction in the unevenness of the original cargo flow from the lava in the experimental conditions without changing the design of the lava conveyor is achieved by stepwise control of the conveyor speed with two-speed drive motors with a ratio of low and high speeds is less, but is less.

Features of application of simplified method of power calculation of plane trusses under conditions of forced oscillations

2021-07-13T11:02:37+00:00

Kholodniak Yu. S., Podliesnyi S. V., Kaporovych S. V. Features of application of simplified method of power calculation of plane trusses under conditions of forced oscillations // Herald of the DSEA. – 2019. – № 2 (46). – Р. 103–113.

The analysis of existing methods of power calculation of trusses under the influence of forced oscillations is performed. When considering the forced oscillations of flat trusses, two-dimensional models are used, which are complex for wide practical use. Their implementation requires in-depth mathematical training and complex computational tools. Therefore, they are difficult to apply in normal engineering practice. Simplified techniques oscillating force analysis of trusses does not exist. The aim of this work is to develop a simplified two-dimensional mathematical model of forced oscillations of flat trusses, followed by the use of this model in their power calculations. The mathematical model proposed in this paper describes the oscillations of a weightless truss with a point mass with simultaneous action of vertical and horizontal harmonic disturbing forces on them. The model is based on the method of forces, establishes a link between the movements of the trusses and the forces that act on it. Together with the model, the dependences for calculating the resonant frequencies of the oscillatory system are obtained. The performed developments allow to determine the dynamic characteristics of the oscillatory process and to calculate the strength, stiffness and stability of the truss. The method of such calculation is implemented in Mathcad15 and has been successfully tested on a number of educational tasks. The results of the work can be useful for students and teachers of technical universities, as well as practitioners performing power calculations.

Prospects for improving the management system for DSP-15

2021-07-13T11:02:36+00:00

Voloshin A. I., Tsyganash V. E. Prospects for improving the management system for DSP-15 // Herald of the DSEA. – 2019. – № 2 (46). – P. 114–117.

The analysis of the control system developed for the DSP-15 arc steel-smelting furnace was carried out, its drawbacks were noted and promising solutions were identified for further improvement of this system. An approach is proposed to determine the optimality of the operating mode of the power circuit of an object, on the one hand, invariant to the size and shape of the input signals, which may not be differentiable, and on the other hand, it is relatively easy to implement. The possibility of representing the criterion for optimizing both in the phase-frequency domain (PFD) and in the time domain allows one to formalize the variation principle of reciprocity in these areas and consider the obtained values as clusters of system paradigms that complement each other well. When presenting signals in the PFD, this makes it possible to reduce the dimensionality of space and at the same time take into account the current changes occurring in it due to the introduction of a relative reference system. Such an approach to estimating the change in energy in the system is also convenient because, with optimal operation of the system, it is possible to combine the range of acceptable values and lead the process without approaching the optimal trajectory as in existing methods, but conduct it directly along this trajectory, which positively affects the efficiency energy conversion. The advantage of this method is to increase the speed of the control system and the possibility of more efficient control using the optimizer. Improving the efficiency of the optimizer contributes to the selection of low-frequency component, which characterizes the power, and allows better alignment of the effective performance ranges of the optimizer with the analyzed signals of the control system. To confirm and implement the marked advantages of the system it is planned to carry out tests in two stages.

The use of modern systems of engineering analysis in the design of equipment

2021-07-13T11:02:34+00:00

Hurkovskaya S. S., Krasovsky S. S. The use of modern systems of engineering analysis in the design of equipment // Herald of the DSEA. – 2019. – № 2 (46). – P. 118–122.

This article discusses the need to introduce modern computer simulation and engineering analysis methods based on FEM into the educational process. Engineering analysis programs based on FEM allow with sufficient efficiency and accuracy to evaluate the behavior of structures that do not fit into the canons of analytical and "semi-analytical" dependencies. The use of a full range of computer-aided design systems reduces the material consumption of a product by 20–25%, production costs by 15–20 %, shortens the product creation cycle by about 2 times, improves the quality of the product and, as a result, improves the competitiveness of the enterprise. In addition, in the process of creating new machines, it is sometimes extremely difficult or very expensive to carry out their tests under the conditions provided by the field of application. At the same time, the equipment being created must have high reliability, durability and performance after mastering mass production. Abaqus, the most popular and powerful calculation package in the world, is considered as the main product used to solve the problem. The main stages of the calculation of the stress-strain state of the gearbox with a view to its further modernization, as well as the results of the calculation are considered. The basic principles that should guide the choice of the type and size of the grid of finite elements in order to obtain the most accurate results with minimal machine time are considered. It should always be remembered that the finite element method itself is a method of numerical approximation, and it cannot give absolute accuracy. However, the use of modern CAE computer modeling systems helps the engineer to quickly assess the vulnerabilities in the structure, improve them, and if necessary, upgrade the structure as a whole.

Automation adjustment and control of the installation mode of the electrophysical treatment

2021-07-13T11:02:32+00:00

Jhartovsky A. V., Kravchenko V. I., Borovikov N. U. Automation adjustment and control of the installation mode of the electrophysical treatment // Herald of the DSEA. – 2019. – № 2 (46). – Р. 123–129.

One of the promising methods of improving the wear resistance and reliability of the instrument are the methods of electro-physical processing. Treatment by impulse electric current on a layer of paste from dispersed materials allows to receive coatings from a deposited layer of a given chemical composition with high quality of the surface layer. In developing the equipment for the implementation of pulsed electro physical processing, there are high requirements for compliance with the processing parameters. It matters the energy and power of the electric impulse. It is from the chemical composition of the paste of dispersed materials and these energy parameters depends on the wear resistance of the coating layer obtained on the surface of the tool. The process does not require high energy costs. Among the disadvantages of this method is the need to improve the management of electrical discharge parameters. The work is devoted to the improvement of equipment for electro physical processing. The tasks are to develop a pulse electro physical processing unit and software that provides precise control and compliance with the electrical pulse parameters for controlling operating modes. The device for impulse electro physical processing and software is developed, which provides precise control and observance of the parameters of the electric pulse for control of operating modes. As part of this installation, there are two functional parts of the power and controlling logic, through which the algorithm of the system is implemented. In the developed program implemented algorithms for selecting the mode of operation of the installation, control of the entered values, pulse generation, determination of power and pulse energy. The program is created in the programming language C in the Keil u Vision 5 software environment. The control program is intended to enter parameters of the mode of operation of the installation and control of the entered values, pulse generating, determination of power and pulse energy. The help of the developed program implements the logic and algorithm of the system.

Development of a software algorithm of automatic climate control system using STK «KONTAR»

2021-07-13T11:02:30+00:00

Luta A. V., Tatarenko O. V., Afanasieva M. A. Development of a software algorithm of automatic climate control system using STK «KONTAR» // Herald of the DSEA. – 2019. – № 2 (46). – Р. 130–135.

In the article the automatic climate control system of the office was developed by developing of the software algorithm with the help of STK «KONTAR». The complex «KONTAR» of modular devices is intended for the solution of a wide range of tasks of automation of heat supply, ventilation, air conditioning, automation of boilers, electric heaters and other power plants. The software and hardware complex of the Moscow Thermal Automation Plant is a system of modules that perform the common task of distributed control and information gathering, interconnected interfaces and common protocols of exchange. The functional scheme of the automatic climate control system was developed. The software algorithm of the climate control system in the office was developed using the Kongraph software environment. In the developed software algorithm the systems of control of shutters, temperature control, level of humidity and level of carbonic gas in the office were implemented. The software algorithm of shutters control of air supply was developed. The software algorithm of humidity regulation in the office was developed. The software algorithm of control of level of carbonic gas in the office was developed. The software algorithms of master-controller MC8, slave-controller MC5 and relay module MR8 by the functional block diagram language in the Kongraph software environment were developed. The conversion and translation of developed software algorithms was implemented by using the Keil software environment. Console software environment was used in order to download bin files gotten after translation into controllers. Developed software algorithm of the automatic climate control system in the office be using STK «KONTAR» can be used in other apartments. In order to adapt it for other apartments it is necessary to correct the specified parameters of temperature, humidity and level of carbonic gas if conditions are different.

Designing of wireless remote control of an automated climate control system indoor

2021-07-13T11:02:28+00:00

Luta A. V., Hryakov A. V., Afanasieva M. A. Designing of wireless remote control of an automated climate control system indoor // Herald of the DSEA. – 2019. – № 2 (46). – Р. 136 –140.

In order to improve the usability of the automated climate control system in the room, a wireless control panel based on the laboratory stand - the software and hardware complex KONTAR of the Moscow Thermal Automation Plant, equipped with controllers, sensors and actuators used in climate control systems for indoor air was developed in the article. The wireless control panel of the automated microclimate control system was designed for the previously developed system of automatic control of air temperature and the air ventilation system in the room. Using this wireless remote control at any time, you can perform some operations for changing the climatic parameters in the room without getting up from the workplace, very easily, by pressing the buttons on the wireless control panel. Software algorithms of automatic control of air temperature and air ventilation in the room were successfully implemented on the stands of an experimental model of a climate control system based on instruments of the KONTAR software complex. It provided the basis for developing a wireless control panel of this climate control system. To fully cover the functionality of the system in the wireless control panel 4 buttons are implemented with functions: switching between automatic and automated control modes; on / off the air heating system; on / off the air cooling system; on / off the air ventilation system. KiCad software was used for designing electrical circuit diagrams and printed circuit boards. Electrical circuit diagrams of the receiver and transmitter have been developed. An electrical circuit diagram of the interface board has been developed. Designed circuit board has been developed. The developed schemes and the wireless control panel can be used in automated climate control systems in the room.

Electric power system efficiency improvement

2021-07-13T11:02:26+00:00

Tsiganash V. E., Beloivanenko Y. S. Electric power system efficiency improvement // Herald of the DSEA. – 2019. – № 2 (46). – P. 141–144.

This work considered the possibility of developing a new method of optimal control and introducing “in large” optimization into the process of energy conversion. That is, to be able to make optimal use of resources at each stage of energy conversion, in all modes of system operation, using all available resources, subject to the obligatory observance of many actual existing restrictions, which are not possible to neglect: energy, information, computing and others. The main goal of this approach to solving the optimization problem is to increase the dynamic properties of the electric power system. To solve this problem, a new optimal control criterion was proposed by us and based on the power supply factor. This criterion makes it possible to develop a model for the process of energy transformation in which measurements and filtering on the one side, management and regulation on the other side are in particular interrelation between duality. The proposed criterion, based on the power supply, makes it possible to abandon parametric optimization and implement the solution of the problem directly through the functional, to be able to represent signals in both the frequency and time domains, significantly expanding the area of its use. This principle of duality allows the multi-stage task to be presented not in the form of a multi-stage “decision tree” as in dynamic programming, but only in three stages of reference - relative, absolute and figurative. Reducing the steps significantly increases the speed of the task solution process. This effect has been confirmed in industrial conditions and in induction and arc steel-smelting furnaces.

Development of an information system for the approximate finding of indicators of an athlete thrower using mathematical modeling of nucleus pushing and the use of neural network technologies

2021-07-13T11:02:25+00:00

Melnykov O. Yu., Kadatsky M. A. Development of an information system for the approximate finding of indicators of an athlete thrower using mathematical modeling of nucleus pushing and the use of neural network technologies // Herald of the DSEA. – 2019. – № 2 (46). – P. 145–149.

The thesis describes the main factors affecting the range of the nucleus. A formula is given for calculating the range, from which it follows that the smaller the force acting on the core, the greater should be the direction angle of this force, and at a certain angle for an angle, an optimal combination of all quantities occurs, which leads to a maximum range of the projectile. The task of designing a system is formulated - an application capable of calculating the main indicators and the result of an athlete in order to use them in the training process to achieve maximum communication between the force and speed of the thrower. An information model of such a system was developed in the form of a set of UML diagrams (use-case diagram, class diagram). Software implementation of the model is described. The results of the software product, showing how fast, with what angle of release and with what force an athlete must push the core to achieve the maximum range of flight, are given. It is concluded that the description of sports equipment solely by the equations of mechanics may not take into account a number of factors which, being of minor significance for the absolute values of the results, can have a serious impact on the relative indicators. The possibility of using modern methods to solve the problem of forecasting is substantiated. The data on the characteristics of eight athletes (age, height, body weight, the preferred method of throwing), as well as their athletic performance (initial speed of the nucleus, throwing angle, height of free hand and distance of flight) are given. Two forecasting tasks were formulated: based on the available data on the age, height, and body mass of the athlete, as well as the characteristics of the core flight, determine the range of this flight; according to the available data on the age, height, body mass of the athlete, as well as the range of the kernel’s flight, determine the optimal combination of flight characteristics – initial velocity, angle and separation height. A method of artificial neural networks with a two-layer perceptron architecture, an activation function by sigmoid, and an error back-propagation algorithm for network training is proposed. Examples of calculation in the environment of Deductor Studio Lite are given.

Raising of non-stationary border task of filtration of liquid in a porous environment

2021-07-13T11:02:22+00:00

Molchanov V. F., Chernyshov А. V. Raising of non-stationary border task of filtration of liquid in a porous environment // Herald of the DSEA. – 2019. – № 2 (46). – P. 150–154.

In the article conformities to the law of process of filtration of technological liquids are investigational through porous materials. On the finish operations of metal-workingness an important value is acquired by application of lubricating-coolings liquids. In the process of exploitation of liquid continuously and intensively contaminated the particulate matters of metal-workingness. For renewal of primary properties technological liquids are purged from mechanical admixtures. A most wideuse is got by the methods of cleaning of technological liquids by filtration. Use of filtration for cleaning of technological liquids most effectively, because during filtration through the layer of porous materials it is possible to attain complete extraction of particulate matters from liquids. However features of structure of poresing space cause row of the specific phenomena, arising up at motion of liquids in ductings of porous environment. A research purpose is a study and establishments of conformity to the law of process of filtration of technological liquids through porous materials. During filtration of technological liquids through the layer of porous materials the porous environment of filter partition is increased with a change its porosity. A change porosity takes a place due to diminishing of volume of pores of poresing space, because particulate matters together with a liquid get to the pores of ductings of poresing space and hang up in them. The conducted researches allowed to expose and study conformities to the law of process of filtration and set the law of change porosity of porous environment. On the basis of the set law differential equalization which allows at the set initial and scope conditions to formulate raising task of filtration of liquid through the layer of particulate matters of variable porous environment of filter partition is shown out

Mathematical modeling of the formation of a multidimensional assessment of the student

2021-07-13T11:02:20+00:00

Isikova N. P., Reshetnyak T. V., Ovsyannikov R. R. Mathematical modeling of the formation of a multidimensional assessment of the student // Herald of the DSEA. – 2019. – № 2 (46). – P. 155–160.

The article describes the method of integral assessments used in the construction of mathematical models in the educational process. A review conducted of the sources on the design of integrated assessments at assessing the knowledge and skills of a student and an assessment of the quality of education in an educational institution. The criteria used for the analysis of the educational level of the student are considered. The method of using additive, multiplicative and additive-multiplicative convolution is given. The advantages and disadvantages of using these methods for the construction of an integrated assessment were underlined. Proposed to use the Choke fuzzy integral to eliminate these drawbacks. The advantages and disadvantages of this method are considered. To provide a high-quality assessment of the student, a multi-dimensional assessment offered. Proposed to include data on the psychological characteristic of the student in the process of building a multidimensional assessment of the student. These types of data generated at the request of a teacher, psychologist, student or parents. The multiparameter assessment contains resulting from the check, processed in a special way and combined into a single completely psychological and pedagogical information about the results of the education of the student. Multi-parameter assessment uses the criteria for assessing the knowledge, skills, abilities and personality characteristics of the student, as well as his creative development. The method of multidimensional assessment, proposed for use in assessing the student, allows you to get a comprehensive assessment of the knowledge and skills of the student, as well as allow you to describe his personal characteristics and creative development. Monitoring the dynamics of a multi-parameter assessment will allow you to track the development of each student during the completely educational process

Development of a neural network computer model for managing a major educational system

2021-07-13T11:02:19+00:00

Reshetnyak T. V., Isikova N. P. Development of a neural network computer model for managing a major educational system // Herald of the DSEA. – 2019. – № 2 (46). – P. 161–164.

The article analyzes the relevance of the task of increasing the efficiency of the functioning of a large educational system. The features of modernization of vocational education in Ukraine are considered. The problems of the existence of a modern school are determined. The possibility of using artificial neural networks as a tool for solving problems of improving the quality of management is considered. The importance of timely forecasting was emphasized to increase the efficiency of managerial decision-making and reduce the risks of unpleasant consequences. As an output for the constructed model, an indicator for assessing educational institutions is proposed. Based on the selected indicators of the criteria of quality, accessibility and efficiency of resource use and the final assessment of educational institutions, a neural network model was built that will allow us to predict the level of the final rating of the educational institution. A graph was built that demonstrates a graphical view of a neural network consisting of neurons and synoptic connections. To assess the degree of deviation of the predicted data from the accepted as a reference, a dispersion diagram was built. When visualizing the diagram, two lines were constructed corresponding to the permissible error level. The What-if visualizer was used, which allows you to change the input data and calculate the level of the final grade of schools using the developed model. The possibility of using the constructed neural network model to manage business processes in the educational system in modern socio-economic conditions of Ukraine’s development is emphasized

Mathematical ground of choice of architecture of computer network as an element of informative infrastructure of educational organization

2021-07-13T11:02:17+00:00

Shevchenko N. Yu., Bagach S. G., Potapov D. S. Mathematical ground of choice of architecture of computer network as an element of informative infrastructure of educational organization // Herald of the DSEA. – 2019. – № 2 (46). – P. 165–170.

In the article the question of the effective use of informative resources is considered through the construction of informative infrastructure of organization the inalienable element of that is her computer network. Going is certain near the choice of architecture of computer network as an element of informative infrastructure of educational organization through determination of efficiency of functioning of computer network by means of imitation design. It is marked that computer networks are the discrete systems with stochastic character of functioning, queuing systems, for planning of that an imitation design is used. An imitation design allows to work out recommendations in relation to the topology of network that will provide most efficiency of informative exchange depending on the size of inwardly-network traffic. Efficiency of informative exchange is offered in a computer network with the set structure to estimate through determination of output-input ratio from position of information transfer. For the imitation design of work of computer network a package is used for the imitation design of Simulink, namely for the imitation of permanent stream of requests the built-in are used in SimEvents elements of pseudocasual generation of numbers that are based on the formulas of exponential and discretely-even distribution. It is set on results a design, that most efficiency of informative exchange is arrived at the use of computer network with a topology "star" on condition of the subzero informative loading, and also at the small changes of input stream. At the high entrance loading, and also her dramatic changes the best technical indexes are demonstrated by the network built on the base of topology "binary tree". A conclusion is set forth that the choice of optimal calculable network structure on the basis of estimation of quality of her functioning allows to promote efficiency of informative exchange

Didactic and acmeologic aspects of training gifted students with regard to the theoretical mechanics competitions

2021-07-13T11:02:15+00:00

Podliesnyii S. V., Yerfort Yu. O., Stadnik A. N. Didactic and acmeologic aspects of training gifted students with regard to the theoretical mechanics competitions // Herald of the DSEA. – 2019. – № 2 (46). – P. 171–180.

The training of the specialists with good creative abilities, professional knowledge and skills is necessary to boost the innovative high-tech economy. The higher education industry is focusing on discovering new talent and working with gifted students. Competitions between students represent one of the ways to fulfill the purpose of finding students talented in technics and helping them to develop their creative abilities. This article tackles the didactic and acmeological aspects of such work. After considering the purposes and functions of the competitions the authors come up with propositions of how to improve competitions, they show basic principles of searching for new talent, explain the necessity of this process and provide recommendations on how to organize the learning activities in the best possible way including by selecting tasks for improving creative abilities, finding proper motivation factors and choosing workable benchmarks for assessing student’s achievements. The process of preparing tasks for competitions should fit pedagogical, psychological and methodical criteria. The academic stuff preparing students for technical competitions should be competitive and highly motivated so that they can inspire students to develop their skills and gain knowledge. The good result can be achieved only under condition of achieving the right balance between learning, social and psychological motives when students are keen to work. The authors published the Learning Course for Technical Student which helps to learn how to solve advanced tasks in Theoretical Mechanics. This Course should be considered as methodical support in the system of preparing students for competitions. The authors also propose the method of selecting students for technical competitions