Vol 91, No 6 (2024)

BACKGROUND: Potato is a crop that requires the preparation of a fine-grained structure of the upper tuber-inhabited soil layer to form tubers of the correct shape, as well as to ensure conditions for good soil separation during harvesting. For this purpose, most technologies for cultivating this crop consider for the formation of a profiled field surface. One of the results of global climate changes is an increase in the frequency of heavy rainfall during the growing season. At the same time, the presence of a profiled surface on fields with even a slight slope leads to significant risks of water erosion during heavy rains due to water flowing from the ridge walls into the row spacing. This leads to annual irreparable losses of the fertile soil layer. Therefore, in order to ensure the preservation of the level of natural soil fertility and to eliminate the risks of water erosion when using intensive potato production technologies in the context of global climate changes, it is necessary to improve the technological methods and technical means used to form a profiled field surface.

OBJECTIVE: Protection of soil from water erosion during potato cultivation on a profiled field surface by improving technological methods and technical means used to form a profiled field surface, as well as justification of the parameters and modes of their operation.

METHODS: The study object is a non-powered rotary hole-digger mounted on an inter-row cultivator-subsoiler. To select reasonable parameters of working bodies of the hole-digger, theoretical studies were con-ducted on the basis of which the rotor diameter of its vanes was selected. The following assumptions were adopted as initial data for determining the technological parameters of the hole-digger: intensity of downpour; depth of the loosening tines of the row-crop cultivator-subsoiler; the rate of rain absorption by capillaries on medium-loamy soils at a certain degree of field slope. The theoretical calculation of the technological parameters of the hole-digger was performed on the basis of the built paths of the rotor center and its vanes during the working process. The calculation of the parameters of the hole-digger was carried out taking into account that the front and rear walls of a hole are formed by its vane by pushing loose soil during rolling with a step t relative to a fixed point at a certain depth h, the step of the hole-digger’s vanes t is determined by the design parameters of the rotor: diameter D and the number of vanes on it.

RESULTS: In order to determine the number of holes per linear meter, the volume of water that gets between the rows during a downpour was calculated depending on their inter-row width. The calculation results showed that with a precipitation intensity of 15 mm/h the number of holes per linear meter of the profiled surface of the field varies from 2.4 to 3.1 pcs/m. These data made it possible to deter-mine the reasonable parameters of the hole-digger for protection against water erosion of the fields located on slopes when cultivating potatoes on the profiled surface.

CONCLUSIONS: An effective method for preventing water erosion on the profiled surface of a field when cultivating potatoes is deep loosening between rows with simultaneous formation of holes at the bottom of the furrow. For this purpose, it is proposed to use a non-powered rotary hole-digger. When using a hole-digger with a rotor diameter of 600 mm the number of holes per linear meter varies from 2.4 pcs/m with a inter row spacing of 70 cm to 3.1 pcs/m with a inter row spacing of 90 cm. For reliable protection of soil from water erosion, it is enough to install 4 vanes on the rotor with the inter-row spacing of 70 cm, 5 vanes with the inter-row spacing of 75 and 80 cm, and 6 vanes will be required with the inter-row spacing of 90 cm.

BACKGROUND: When applied to the soil during the cultivation process, the moisture and air permeability of the layer improves, which favors the activity of microorganisms and the growth and development of plants. The increase in the yield of agricultural crop production directly depends on the level of technology of the new generation machinery. Therefore, the improvement of their designs in order to increase the level of technology of the new generation machinery is a relevant task of the agricultural industry.

OBJECTIVE: Systematization and ordering of known designs of steam cultivators, identification of their advantages and disadvantages.

METHODS: The method of monographic examination of the structures of steam cultivators, both the machine as a whole and the main working bodies separately, was used on the basis of well-known scientific studies and the results of state tests. Thus, the really working steam cultivators recommended for use in agricultural production were considered. In addition, the patented designs of the working bodies of steam cultivators were analyzed. The efficiency of steam cultivators was determined based on the results of state tests of the Povolzhsky, Northwestern, Siberian, Kuban, North Caucasian, Central Chernozem, Kirov, Vladimir machinery testing stations over the past 10 years.

RESULTS: The paper contains a review of steam cultivators and their designs. The classification of cultivators by 3 types is given: by the type of main working bodies (paws); by the type of additional working bodies (rollers, harrows, rods); by the type of attachment to the tractor (trailed, mounted). Their advantages and disadvantages are considered. A review of studies on improving the designs of steam cultivators to improve the tillage quality and to reduce energy consumption for tillage is given. The working bodies (paws), the frame parts for mounting the main working bodies, the strut and the design of additional working bodies of steam cultivators are being modernized. Theoretical studies on improving the efficiency of cultivators are considered. The conditions for achieving and improving the tillage quality with a steam cultivator are revealed by determining the relationship of parameters with the indicators of the technological process. The application of computer simulation modeling in solving theoretical problems of study of the new working bodies is considered, advantages and disadvantages are revealed.

CONCLUSIONS: The systematization of steam cultivators presented in this paper is helpful to determine ways to further improvement of them.

BACKGROUND: An increase in the quantity and quality of soybean crop seed can be achieved by using a combine harvester with two-phase threshing, since during conventional post-harvest processing, the yield of seed material is reduced due to the traumatic effects of the working organs of cleaning machines. One of the most important processes for obtaining soybean seed fraction is the purification process. In this regard, the improvement of air-sieve cleaning systems of combine harvesters is the most important task of combine engineering.

OBJECTIVE: Identification of the patterns of changes in the airflow rate depending on the operating parameters of the air-sieve cleaning system of a combine harvester.

MATERIALS AND METHODS: To study the parameters of the airflow, the experimental part of the research was carried out using a laboratory bench simulating the operation of a combine harvester cleaning system. A total of 43 experiments were conducted in three repetitions according to the matrix of the multifactorial experiment and 4 regression equations were obtained.

RESULTS: Empirical dependences that describe the change in the airflow rate behind the sieve depending on various parameters of the grain cleaning system are presented. The influence of the operating parameters of the air-sieve cleaning system of a combine harvester on the nature of the airflow distribution is studied. The change in the airflow rate at the outlet of the fan diffuser and the flow rate distribution over the entire surface of the upper sieve are considered.

CONCLUSIONS: The obtained patterns will be helpful to optimize the airflow distribution along the entire length of the sieve of the air-sieve cleaning system and to create prerequisites for automating the harvesting process. The decoded regression equations will be the basis for the development of an algorithm for automatic control of the parameters of the air-sieve cleaning of the combine harvester.

BACKGROUND: Topological optimization is widely used in aircraft construction and architecture, but is still of limited use in heavy mechanical engineering. At the same time, the metal cutting for production of working bodies, frames and other structures is often carried out by plasma cutters with computer numerical control. This makes it possible to produce flat parts of almost any complexity. Consequently, there is a field for using the topology optimization methods with no need to use additive technologies to create three-dimensional structures.

OBJECTIVE: Weight reduction of the structural components of the front loader’s working equipment without loss of rigidity and strength, as compared with traditional designs; exploration of the capabilities of topological optimization for solving this problem.

METHODS: The DM-30 loader was used as the base machine. Its work equipment was converted into a set of flat-shaped design volumes, to which the topological optimization methods of the Autodesk Inventor Professional (AIP) software package were applied. As the steel structure of the working equipment is subject to load in different directions during operation, a method of sequential generation of parts’ shapes for each design position and synthesis of all the shapes into a single object was used. The forces acting on the components of the working equipment were determined with dynamic simulation of the design positions for the base machine which made it possible to study the majority of operation cases.

RESULTS: As a result, the weight of the front loader was reduced by 36% while sustaining the same strength characteristics.

CONCLUSIONS: The proposed method of formation the optimized steel structure is capable of using simple topological optimization modules and obtaining up to 40% less metal-consuming spatial structures.

BACKGROUND: Highly-mobile wheeled vehicles are designed to move on roads and terrain in various road and soil conditions, which is accompanied by frequent and significant changes in traction forces and rolling resistance forces. In this regard, in order to maintain vehicle mobility and to ensure low energy costs when performing transport tasks, it is necessary to continuously change the operating mode during motion from the completely locked mode to the differential mode in the case of a mechanical transmission. At the same time, the transmission operating mode selected by the driver is not always reasonable. Thus, the development of a law for controlling the power supplied to the propulsion system, ensuring minimal energy losses while maintaining vehicle mobility in widely varying road conditions, is a relevant task.

OBJECTIVE: Increasing the energy efficiency of highly-mobile wheeled vehicles by applying a control law for the power supplied to the propulsion system, adaptive to driving conditions.

METHODS: Increasing the energy efficiency of motion can be achieved by means of reducing losses due to wheel slipping by controlling the power supplied to the propulsion system. It is advisable to obtain the control law as a result of solving an optimization problem, where the loss power is chosen as the objective function, and the traction forces developed on each of the wheels are chosen as the varied values. At the same time, in order to maintain the ability of vehicle to move, it is necessary to take into account that the total traction force on all wheels must be determined by external conditions and be provided by the powertrain. To solve the optimization problem, the Lagrange multiplier method was used.

RESULTS: The conducted studies made it possible to obtain a unified law of adaptive control of the power supplied to the propulsion system in analytical form, applicable in a wide range of road conditions in both straight and curvilinear motion, ensuring the distribution of moments across the driving wheels of the machine close to optimal.

CONCLUSIONS: The application of the developed law for controlling the power supplied to the propulsion system, based on the use of information about the longitudinal and vertical forces, rotational velocities and steer angles of the wheels during the motion, will improve the efficiency of performing transport tasks when moving a vehicle in continuously changing road conditions. This is achieved due to reducing the workload on the driver in terms of controlling differential locks in comparison with a manual transmission both in straight and curvilinear motion.

BACKGROUND: Mechanized pulling of crops is carried out by the most efficient flax milling machines with transverse belt-disc channels. At the same time, the analysis of the works showed that the action of the inertia forces of plants when moving in curved pulling channels is not analyzed, their effect on the quality of the technological process is not found, the condition for pulling all plants from the soil without their excessive flattening, which reduces their effectiveness, is not determined.

OBJECTIVE: Theoretical and experimental study of the process of pulling flax plants with devices with transverse belt-disc channels.

METHODS: Experimental studies were carried out according to well-known and developed methods, with an assessment of flax products according to the GOST standards. The influence of the centrifugal inertia forces of plants on the bending of the plant belt, stretching of its upper part and loss of flax balls, and the condition of pulling all plants, taking into account the maximal strength of the tearing resistance of plants, were determined. Standard equipment and developed installations were used.

RESULTS: Dependences were obtained for determining the inertia forces of plants in the zones of pulling pulleys and deflecting rollers, and bending moments created by the inertia forces of plants and acting on plants, as well as the speed of the pulling belt, to prevent greater inertia forces of plants, negatively affecting the quality of work, and the condition of pulling all plants from the soil with taking into account the maximal strength of the stretching resistance. The limit value of the bending angle of the plant belt, which should not exceed 20°, has been found experimentally.

CONCLUSIONS: When designing flax milling machines with belt-disc channels to reduce the inertia forces, it is necessary that the elements of adjacent milling sections have the same size and shape as possible, which will reduce the forces of inertia of plants, eliminate peak pressures in a channel, increase the durability of the belt, reduce losses of flax products.

BACKGROUND: The paper discusses the impact of the Khishchnik-3930 and Khishchnik-3940 all-terrain vehicles with ultra-low pressure tyres on soil with various equipment configurations.

OBJECTIVE: Study of the influence of the Belshina Arctic trans 28.1R26 Bel -44 and the Mammoth 1780×710-32 tyres in the context of evaluation of the design parameters of the propulsors of wheeled all-terrain vehicles of various categories on soil and determination of specific soil pressure of the Khishchnik-3930 and Khishchnik-3940 all-terrain vehicles with ultra-low pressure tyres.

METHODS: Determination of the tyre pressure (4 and 50 kPa) is given according to the results of the impact of the machinery of various categories and configurations of the wheel equipment and the additional equipment on soil in accordance with GOST R 58656-2019 in the natural and operating conditions of the regions of the Far North and the equivalent areas of the Russian Federation are given.

RESULTS: The results of theoretical and experimental studies of the impact of propulsors of the all-terrain vehicles on soil are presented.

CONCLUSIONS: The methods and ways of reduction of negative impact of the all-terrain vehicles’ propulsors on soil are proposed. The practical value of the study lies in practical recommendations on the possibility of approbation of the study results in the natural and operating conditions of the regions of the Far North and the equivalent areas.

BACKGROUND: Solving the problem of ensuring the reliability of internal combustion engines during operation requires an integrated approach, solved in different directions. Solving these problems is a relevant complex task. The main issues are operating conditions, the type of fuel used, monitoring the indicators of engine oils, as well as the development of reasonable service life for the latter. When supporting the operational properties of engine oils, monitoring the basic characteristics of the operating oil is relevant.

OBJECTIVE: Assessment of the accumulation of contamination and wear products in the M10G2 oil of diesel engines and diesel-based gas engines. Use of theoretical equations for assessment of change in percentage of contamination products and conducting laboratory analyses aimed to assessment of content of contamination and wear products as well as particle size in the oil.

METHODS: One of the main ways to reduce increased wear and carbon formation in engines is blending additives to the engine oil that can neutralize the corrosive and carbon-forming effects of sulfur fuel combustion products, having high antioxidant and detergent properties. Products of organic and inorganic origin and mechanical impurities of wear products accumulate in motor oil as a result of long-term operation. After the first 100 hours of oil operation, it contains certain amounts of contamination and wear products, as well as insoluble products of oxidation and wear of engine parts. During the study, the laws of lubrication theory, methods of design of experiment and mathematical statistics, as well as methods based on existing regulatory documents were used. Processing methods in the Microsoft Office Excel application packages were used for processing of experimental data.

RESULTS: The process of oil aging in internal combustion engines and the factors influencing the aging of engine oil are considered. Using the analytical equations, changes in the concentration of wear products and contamination of the oil of a diesel-based gas engine are calculated, and graphical dependences of oil indicators on operating time are given.

CONCLUSIONS: The practical value of the study lies in the fact that, using theoretical equations, it is possible to assess the accumulation of contamination products in the oil; based on the results of laboratory tests, it is possible to assess the percentage of wear products and contamination in the oil. Operation of diesel and diesel-based gas engines with oil having high percentage of contaminants and wear products leads to reduced engine reliability, reduced lubricating oil lifespan, accelerated wear of individual parts, varnish formation and sedimentation on separate engine parts.

BACKGROUND: The 3D printing technology is rapidly developing, giving the opportunities for the manufacturing of parts with specified properties. However, the mechanical characteristics of materials obtained by 3D printing often do not meet the requirements for various applications, for example, agricultural machinery. Increasing the impact strength of materials produced by 3D printing is a relevant task for expanding their application.

OBJECTIVE: Study of the effect of heat treatment (annealing) and 3D printing parameters (layer thickness, filling percentage) on the impact strength of the polylactide (PLA) samples.

METHODS: An experimental study was conducted using the PLA samples made by 3D printing with variable parameters: layer thickness (0.15 mm, 0.20 mm, 0.25 mm) and percentage of filling (50%, 75%, 100%). The samples were annealed at a temperature of 80 °C for 2 hours. The impact strength was determined by the Charpy method using standard test equipment.

RESULTS: 27 PLA samples were included in the study. Annealing significantly increases the impact strength of all samples. The dependence of the impact strength on the thickness of the layer and the percentage of filling was observed. The maximum impact strength (2.58 ± 0.12 J/cm²) was achieved with a layer thickness of 0.15 mm and 100% filling. Statistical analysis of the results performed using ANOVA (p < 0.001) showed a significant influence of all factors on the impact strength.

CONCLUSIONS: The results obtained demonstrate that annealing and optimization of 3D printing parameters (layer thickness, filling percentage) can increase the impact strength of materials obtained by 3D printing from PLA. The optimal parameters achieved in this study can be used in development of parts of agricultural machines with improved mechanical properties.

BACKGROUND: The relevance of reasonable ballasting of a new generation of wheeled 4K4a tractors on single (1k) and dual rear (2k’) wheels with an operating weight adjustable over a wide range when used in zonal tillage technologies is shown.

OBJECTIVE: Justification of levels of reasonable ballasting of the new generation wheeled 4K4a tractors in soil cultivation operations.

METHODS: The specific weight of the tractor is taken as the main adapting parameter, the reference value of which is the ratio of the operating weight with full ballast to the engine power output in the nominal traction mode for operations of the first group (moldboard plowing) at a velocity of 2.50 m/s (9.0 km/h), ensuring full implementation of potential capabilities.

RESULTS: The reference levels of specific gravity based on the results of modeling and experiments are 67.3 (1k) and 70.0 (2k’) kg/kW and determine the maximum value of the operating weight of a tractor of the declared power. For operations with lower energy intensity, the second and third groups, with a nominal velocity of 2.90 and 3.33 m/s, its optimal values are reduced by 16 and 33% respectively, which determines the feasibility of their implementation with minimal ballasting with a specific gravity of 58.0–60.0 kg/kW. At the same time, the reasonable use of a tractor with full ballast is limited to the velocity range of 7.6–10.0 km/h in operations of the first and second groups, and the velocity range of 10.0–13.0 km/h with a minimum ballast when performing operations of the second and third groups. Tractor operation with full ballast during operations of the third group at a velocity of 12–13 km/h is accompanied by an increase in the harmful impact of propulsion on the soil and an increase in fuel consumption to 0.7–0.9 l/h to move each ton of excess mass.

CONCLUSIONS: The proposed ballasting options ensure the implementation of the potential capabilities of the new generation tractors at operational tillage technologies with a minimal increase in operating labor intensity.

BACKGROUND: The conducted laboratory studies of the effect of a low-frequency magnetic field on the productivity of grain seeds revealed stimulation of the biophysical and bio-chemical properties of the seeds, an increase in their germination, germination energy and plant growth, which corresponds to the research plan of the Federal Scientific and Technical Program for the Development of breeding and seed production of cereals until 2030.

OBJECTIVE: To study the effect of a low-frequency electromagnetic field on the productivity indicators of an industrial batch of grain seeds.

METHODS: The research was carried out in accordance with the GOST on a prototype of the equipment for electromagnetic exposure on 11 varieties of grain seeds according to 5 indicators of productivity: laboratory germination, field germination, germination density, plant density before harvesting, yield rate. The varied parameters were the irradiation modes: frequency (Hz), magnetic induction (mT), exposure time (min).

RESULTS: An increase in the yield rate of the irradiated industrial batches of grain seeds compared with the non-irradiated ones up to 22% was found, while an increase in laboratory germination up to 17%, field germination up to 10%, germination density up to 10%, plant density before harvesting up to 11% were found.

CONCLUSIONS: The effectiveness of the irradiation modes of industrial seed masses has been proven by an increase in yield rate for the following varieties: 16 Hz, 25 mT, 25 min — for the Ester spring wheat varieties (an increase of 13%); 50 Hz, 25 mT, 25 min — for the Znatny spring barley (an increase of 5%); 75 Hz, 25 mT, 5 min — for the Povolzhskaya 21 winter wheat varieties (increase of 22%); 16 Hz, 10 mT, 25 min — for the Povolzhskaya Niva winter wheat (increase of 19%), Moskovskaya 39 (increase of 13%).