Title of the article | ON THE CHOICE OF MODERN STRUCTURAL METAL MATERIAL FOR HIGH-DUTY MECHANICAL SYSTEMS. PART 1 |
Authors |
SOSNOVSKIY Leonid A., D. Sc. in Eng., Prof., Professor of the Department “Locomotives”, Belarusian State University of Transport, Gomel, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. |
In the section | TRIBO-FATIGUE SYSTEMS MECHANICS |
Year | 2022 |
Issue | 3(60) |
Pages | 85–96 |
Type of article | RAR |
Index UDK | 669.13.018; 669.131.7 |
DOI | https://doi.org/10.46864/1995-0470-2022-3-60-85-96 |
Abstract | It is shown that when solving the problems of assurance of quality, reliability, competitiveness of high-duty mechanical systems, metal and a complex of its mechanical and service properties are of fundamental importance. Steel cast iron MONICA (Mo–Ni–Cu) (patent BY, no. 15617) exhibits an unconventional and unique ability to lose brittleness (increase viscosity) with increasing strength. In terms of service properties, it is not inferior to alloyed heat-strengthened steels. This makes it possible to recommend it for the manufacture of various highly loaded parts and assemblies of modern technology. The article provides several examples of the effective use of MONICA for the manufacture of cast knives for cutting and chopping devices of forage harvesters (Hi-Tech), large-sized gear wheels with a diameter of 500 mm for final drives of agricultural combines (know-how), as well as experimental cast rails for railway transport (Hi-Tech). A complex of laboratory and full-scale tests has convincingly proved that one brand of a new structural material fully provides the required operational reliability of many and different tribo-fatigue systems, the performance of which is determined by many criteria (fatigue, wear, friction, crack resistance) under the action of high repetitive variables and shock-cyclic loads. This determines the unconditional efficiency and competitiveness of critical mechanical systems (tribo-fatigue systems) for modern machines and equipment. |
Keywords | metal; mechanical and service properties; limits of strength, fatigue, crack resistance; wear resistance; stress-strain and limit states; modification; microstructure; MONICA |
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Title of the article | FINITE ELEMENT MODELING OF THE PROBLEM OF STRETCHING A MATERIAL WITH ZONES OF ALTERED STRUCTURE |
Authors |
VERAMEICHYK Andrei I., Ph. D. in Phys. and Math., Assoc. Prof., Senior Researcher of the Test Center, Brest State Technical University, Brest, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. NERODA Mikhail V., Ph. D. in Eng., Assoc. Prof., First Vice-Rector, Brest State Technical University, Brest, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. KHOLODAR Boris G., Ph. D. in Eng., Assoc. Prof., Senior Researcher of the Research Department, Brest State Technical University, Brest, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. |
In the section | MECHANICS OF DEFORMED SOLIDS |
Year | 2022 |
Issue | 3(60) |
Pages | 77–84 |
Type of article | RAR |
Index UDK | 004.94:620.172 |
DOI | https://doi.org/10.46864/1995-0470-2022-3-60-77-84 |
Abstract | The article considers computer simulation of tensile tests of a rectangular cross-section rod with zones formed during heat treatment by a moving highly concentrated heat source, the characteristics of which differ from the properties of the base material. Based on the results of finite element modeling, the stress-strain state of a rod with one or more zones of altered structure along its entire length and on part of the length is investigated. The stress concentration coefficients in the vicinity of the treatment zones are determined. |
Keywords | mechanical characteristics of the material, stress concentration coefficient, finite element method, local impact, material structure, stress intensity |
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Title of the article | DETERMINATION OF THE EFFECTIVE THICKNESS OF HARDENED LAYER OF CARBURIZED GEARS |
Authors |
RUDENKO Sergei P., Ph. D. in Eng., Leading Researcher of the Laboratory of Metallurgy in Mechanical Engineering, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. VALKO Aleksandr L., Senior Researcher of the Laboratory of Metallurgy in Mechanical Engineering, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">valсThis email address is being protected from spambots. You need JavaScript enabled to view it. SANDOMIRSKI Sergei G., D. Sc. in Eng., Assoc. Prof., Head of the Laboratory of Metallurgy in Mechanical Engineering, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. |
In the section | MECHANICAL ENGINEERING MATERIALS AND TECHNOLOGIES |
Year | 2022 |
Issue | 3(60) |
Pages | 61–67 |
Type of article | RAR |
Index UDK | 669.15:620.178.1 |
DOI | https://doi.org/10.46864/1995-0470-2022-3-60-61-67 |
Abstract | The methods are considered for determining the effective thickness of the hardened layer of metal parts listed in the standards STB 2307-2013 and STB ISO 18203-2019. The ambiguity of interpretation of the concept of effective thickness hэф of the hardened layer up to the half-transition zone is established for control of gears after the chemical heat treatment: carburizing and hardening. In practice, hэф is determined by the Vickers hardness distribution under the relevant load. In accordance with the standard ASTM E140-07, the Vickers hardness value of 50 HRC represents the Vickers hardness of 513 HV for non-austenitic structural steels when tested at 294.2 N. When testing Vickers hardness at lower loads, conversion tables or dependencies must be used. It has been shown that such measurements are more inaccurate at lower loads. To eliminate errors and increase accuracy of determining hэф of diffusion thickness of gear wheels after chemical-hardening, techniques are compared to determine hэф three: metallographic, mechanical and chemical. The Vickers hardness values determined during tests of structural non-austenitic steels with different loads correspond to the hardness value of 50 HRC. The values obtained can be applied to determine hэф of diffusion layers of surface-hardened parts corresponding to the half-transition zone. |
Keywords | Vickers method, hardness test, analytical dependence, surface layer, half-transition zone, effective thickness |
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Title of the article | VIBRATIONS OF A THREE-LAYER CIRCULAR STEP PLATE UNDER PERIODIC IMPACT |
Authors |
LEONENKO Denis V., D. Sc. in Phys. and Math., Prof., Professor of the Department “Structural Mechanics”, Belarusian State University of Transport, Gomel, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. MARKOVA Marina V., Postgraduate Student of the Department “Structural Mechanics”, Belarusian State University of Transport, Gomel, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. |
In the section | MECHANICS OF DEFORMED SOLIDS |
Year | 2022 |
Issue | 3(60) |
Pages | 68–76 |
Type of article | RAR |
Index UDK | 539.3 |
DOI | https://doi.org/10.46864/1995-0470-2022-3-60-68-76 |
Abstract | Forced oscillations of a three-layer circular plate with step-variable thickness of the outer layers are analyzed. The deformation of the plate is described with the zig-zag theory. In thin border layers of plate Kirchhoff’s hypotheses are valid. In a relatively thick in thickness medium layer Timoshenko’s hypothesis on the straightness and incompressibility of the deformed normal is fulfilled. The equations of motion are derived from Hamilton’s variational principle. A special case of exposure is considered: periodic sequence of strokes with constant intensity. The problem is reduced to finding three required functions in each section, deflection, shear and radial displacement of the median plane of the filler. The solution is presented as a sum of quasi-static and dynamic components of the unknown displacements. Numerical results of the obtained solution are presented. The influence of the impact stress on the oscillatory character is analyzed. |
Keywords | circular three-layer plate, plate with step-variable thickness, forced vibration, periodic strokes |
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Title of the article | SELECTION OF THE RANGE OF GEAR RATIOS OF THE MECHANICAL PART OF THE ELECTROMECHANICAL POWER TRAIN OF THE TRACTOR |
Authors |
ZHDANOVICH Cheslav I., Ph. D. in Eng., Assoc. Prof., Associate Professor of the Department “Tractors”, Belarusian National Technical University, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. KALININ Nikita V., Senior Researcher of the R&D Center “Agricultural Engineering”, Joint Institute of Mechanical Engineering of the NAS of Belarus, Minsk, Republic of Belarus, This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it. |
In the section | MECHANICAL ENGINEERING COMPONENTS |
Year | 2022 |
Issue | 3(60) |
Pages | 52–60 |
Type of article | RAR |
Index UDK | 629.3.014 |
DOI | https://doi.org/10.46864/1995-0470-2022-3-60-52-60 |
Abstract | A method has been developed for selecting the gear ratio of the mechanical part of the power train (MPPT) to work on agricultural operations of a tractor of the 5th drawbar class equipped with an electromechanical power train with a traction induction electric motor (TIM). It is assumed that there are two gears: the high one (n-th) for operation in transport mode and the low one (n–1st) for operation in operational and technological modes. The gear ratio MPPT uМЧТ,n, corresponding to the nth gear, is determined from the condition of ensuring the required maximum velocity of the tractor. The gear ratio of the MPPT uМЧТ(n–1), corresponding to the n–1st gear, must be in the range from the uМЧТ(n–1),р, at which the minimum plowing velocity will be provided at the nominal value of the voltage frequency supplied to the TIM, to the uМЧТ(n–1),max, determined by from the condition of providing the maximum possible velocity range of the tractor with only the n-th gear without overlapping its n–1st gear. A formula is also proposed for determining the value of the uМЧТ(n–1),v, at which the tractor can operate with the maximum velocity permissible for a given agricultural operation. If uМЧТ(n–1),v < uМЧТ(n–1) < uМЧТ(n–1),р, then the entire velocity range for a given agricultural operation will be provided when working in the n–1st gear. In order to determine the uМЧТ(n–1) with the best traction efficiency, it is proposed to carry out tractor traction calculation for the values of uМЧТ(n–1) taken in the range from uМЧТ(n–1),р to uМЧТ(n–1),max with a certain step. After that, for the selected value uМЧТ(n–1), it is necessary to calculate the TIM losses during tractor operation in the entire velocity range provided by the n–1st gear. If the thermal mode of the TIM is not performed when the tractor is moving at low velocities in the n–1st gear, then it is necessary either to take a larger value of the uМЧТ(n–1) at which it is performed, or in case of a small excess of the permissible power losses of the TIM, do not increase the uМЧТ(n–1), but take this into account when designing the TIM cooling system. |
Keywords | tractor, traction induction electric motor, gear ratio, mechanical part of the power train, electromechanical power train, drawbar pull, slipping, theoretical velocity, actual velocity, traction efficiency |
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