Traktory i sel hozmashiny

BACKGROUND: Due to the rapid growth of the electrified transport sector, one of the key issues in designing electrified vehicles is determining the optimal parameters of hybrid powertrains. This paper contains the study of an extra-large class urban passenger vehicle equipped with a hybrid powertrain (HPT) consisting of a rechargeable electrical energy storage system and an electrochemical generator. In order to define optimal parameters of a HPT, the method for synthesis of optimal parameters that accounts for the main design requirements and operational features of the studied vehicle is proposed.

AIM: Determination of the optimal parameters of a hybrid powertrain for a vehicle, taking into account technical and operational parameters and the actual operating modes of an extra-large class urban passenger vehicle.

METHODS: Optimization of the hybrid powertrain parameters is performed using a global search optimization algorithm included in the GlobalToolbox package of the MATLAB software. Simulation modeling methods in the Simulink software are used to calculate the optimization criterion.

RESULTS: The paper presents a formulation of the optimization problem for the hybrid powertrain parameters, a description of the simulation mathematical model in the Simulink software, verification of the mathematical model using the experimental data, and the results of synthesis of optimal parameters for various cell chemistries of the rechargeable electrical energy storage system.

CONCLUSION: As the study result, optimal parameters of the HPT of the extra-large class urban passenger vehicle were defined considering main technical and operational parameters. The practical value of this study lies in the possibility of using the proposed method for determining optimal parameters of hybrid powertrains in the design of commercial vehicles, in particular extra-large class passenger vehicles with a hybrid powertrain based on an electrochemical generator and a rechargeable electrical energy storage system.

BACKGROUND: In a market economy, farms are the main alternative for rural development. One of the conditions for obtaining a good harvest is high-quality soil cultivation. A feature of farms is their small size. Therefore, it is necessary to use small-sized power units to mechanize the processes of cultivating agricultural crops.

AIM: Development of a small-sized traction and transport vehicle for primary soil cultivation in small subsidiary farms and determination of its traction indicators.

METHODS: A design of a small-sized soil-cultivating unit based on a walk-behind tractor has been developed. The proposed small-scale mechanization tool is driven by a motorcycle engine and is equipped with combined working tools: a cutter is located in the front, and a disk gang is at the back. A power analysis was carried out to assess the energy consumption of the proposed unit, including the resistance of the cutter and the disc working element.

RESULTS: As a result, the power costs for the resistance of the cutter and disk working bodies were determined. The dependencies of the total traction resistance on the unit velocity and the depth of soil tillage were obtained.

CONCLUSION: As a result, the operability of the proposed unit for primary soil tillage in small farms has been confirmed.

Modern agricultural machinery enterprises produce combine harvesters of various design solutions, including those with an axial threshing and separation design. The development, improvement and optimization of the parameters of the elements of rotary threshing and separating devices is a relevant technical task.

The aim is to study the working process in the lead-in of various grain harvesters with an axial threshing and separation system in order to identify the problems that arise during their operation and to establish methods for solving them.

The research conducted is based on a comprehensive analysis of the information available on the websites of both domestic and foreign manufacturers of self-propelled grain harvesters. In addition, the research involved studying data from various literature sources regarding changes in the physical and mechanical properties of agricultural plant stems during threshing and the results of assessing the condition of the receiving chambers during industrial operation in agricultural conditions.

The technological process of grain harvesters with an axial threshing and separation system of various manufacturers has been considered. The most loaded element has been identified, which is the intake chamber of the lead-in, as it receives the entire volume of the threshed mass with the maximum mechanical properties of the crop stems. When operating in production conditions, various manufacturers’ grain harvesters have shown through wear of the intake chamber due to the high load. The existing solutions for reducing wear have been found to be insufficiently effective. To reduce wear, it is proposed to optimize the technological process by changing the geometric shape of the receiving chamber.

The practical value of this research lies in identifying the wear of the receiving chamber during operation of grain harvesters with an axial threshing and separation system from various manufacturers in production conditions. The most promising approach to overcome this issue is to modify the technological process by optimizing the geometric shape.

BACKGROUND: The cutting edge of a modern rotary cultivator knife has a complex shape of a spatial curved line and should perform the process of soil cutting with minimal energy consumption and without becoming clogged with weeds. Due to the complexity of the curve shape, a method for analyzing it for fulfilling the condition of weed removal has not been developed yet, which hinders the determination of directions for its improvement.

AIM: Development of a methodology for analyzing the shape of the edge curve of the blade of spatial knives of rotary cultivators to meet the condition of weeds coming off them.

METHODS: The design of the study included: development of a methodology for analyzing the shape of the edge curve of the blades of spatial knives of rotary cultivators; testing of the methodology during the analysis of standard Japanese and Chinese knives.

The objects of the study were the shapes of the edge curves of standard Japanese and Chinese knives. The studies were conducted during 2023 and 2024.

RESULTS: A method for analyzing the shape of the edge curve of the blade of spatial knives of rotary cultivators to meet the condition of weeds coming off them has been developed. Examples of its application for analyzing the shapes of the edge curves of the blades of standard Japanese and Chinese knives are given. A pattern of changes in the wedge angle along the length of their blades was found, and areas of the blades under study with difficulty in removing weeds from them were identified.

CONCLUSION: The proposed method allows quick analysis of the shape of the edge curve of the blades of rotary cultivators to meet the condition of weed removal from it, and identifying areas of the blade from which weed removal is difficult.

BACKGROUND: The paper discusses the process of modeling the motion of grain and foreign impurities carried by the air flow in the grain transportation and cleaning system of a breeding combine harvester, which is necessary to improve the quality of grain cleaning and to optimize the development and adjustment of such cleaning systems.

AIM: Building a digital twin of the transportation and cleaning system with the ability to simulate the motion of particles in the air flow.

METHODS: A digital model of the grain transportation and cleaning system was used as the object of study. Modeling of the process and study of particle movement in an air flow using the discrete element method was carried out at the Don Engineering Center as part of the SRW of the Federal Scientific Agroengineering Center VIM. The particle parameters were selected based on measurements of real impurities in the grain heap of the Anfisa wheat variety.

RESULTS: The composition of the grain heap was clarified, the geometric dimensions and masses of typical particles — grains, chaff, awns, etc. — were measured, their digital models were created. A digital model of the grain transportation and cleaning system of a breeding combine harvester was created, with the help of which a study of the motion of particles in the air flow was carried out, in particular - their paths, motion velocities. The grain heap motion route was modeled from the time it enters the grain intake from the sieves by the time it passes the cyclone filter of the cleaning system. Some air flow parameters were measured on a physical sample of the pneumatic grain transportation and cleaning system installed on a breeding combine harvester.

CONCLUSION: To improve the quality of grain cleaning in a selective combine harvester and optimize the development and configuration of such cleaning systems, the possibility of conducting research in a digital environment for a design requiring optimization of many parameters is considered, using the example of a digital twin of a grain transportation and cleaning system with the ability to simulate particle motion in an air stream.

BACKGROUND: Trailer chassis systems play a crucial role in ensuring the safety and efficiency of cargo transportation. Therefore, when designing the frame, it is necessary to conduct a detailed analysis of stress-strain state using the finite element method. In numerical analysis problems, an important step is to select a suitable finite element model of a semi-trailer frame that ensures an adequate representation of stress and strain distribution. This study conducts a comparative analysis of various approaches to constructing finite element models that differ from each other in terms of the method for transferring load from transported cargo, taking into account contact interactions between elements, as well as the way of modeling the fifth wheel coupling device.

AIM: Development and analysis of computational finite element models of the semi-trailer framework with various options of structural elements joints modeling, methods of load transfer from the truck and the transported cargo.

METHODS: The solution of the given task is carried out using the finite element method in the Siemens NX software package.

RESULTS: During the analysis of various finite element models, it has been found that:

1. When transmitting load through pallets, the difference in stresses reaches 60%.
2. The introduction of a coupling device into the calculation model reduces stresses by up to 25% due to the creation of an additional support surface for the front plate of the semi-trailer.
3. Taking into account the contact between all the contacting elements of the frame and setting the tightening forces of the bolts reduces the stresses in the spars to 60%.

CONCLUSION: As a result of the study, a number of finite element models of the semi-trailer frame were developed and analyzed. The influence of various options for modeling the joints of structural elements, methods of transferring loads from the truck and the transported cargo on the strength characteristics of the frame has been studied. The analysis of the results revealed a significant impact of the addition of pallets, a coupling device and the contact interaction between the elements on the calculation results, which does not allow to conclude that the simplified and detailed models are equivalent. Therefore, when performing calculations using the finite element method, the absence of these elements should not be allowed, since such an assumption may lead to a significant difference in the calculation results.

BACKGROUND: Currently, agricultural equipment faces the challenges of increased wear and tear and limited availability of conventional materials. To replace standard components, innovative solutions are required to improve the mechanical properties of parts while maintaining or reducing their mass. The use of metamaterials created using 3D printing technologies opens up new opportunities for the production of parts with adjustable internal structure, which helps to improve the durability and performance of machines.

AIM: Analysis of the influence of the octagonal correct and incorrect geometric configuration of metamaterials on their mechanical properties in order to develop the application of these materials for agricultural machinery parts that provide increased strength and resistance to deformation.

METHODS: The study was based on numerical modelling using computer-aided design and engineering system. The objects of the study were metamaterials with various configurations of octagonal cells differing in shape, size, number and orientation. A comparative analysis of regular and irregular octagonal structures was carried out as part of the experiment.

RESULTS: The analysis showed that the geometrical structure of metamaterials has a significant influence on their mechanical performance. Regular octagonal structures showed increased stiffness and resistance to deformation, whereas irregular structures were characterized by greater plasticity. Optimization of the internal structure of the materials improved the mechanical properties without significantly increasing the mass of the parts.

CONCLUSION: The study confirmed the feasibility of using 3D printing to create metamaterials with improved mechanical properties by changing the geometric structure. The developed materials can replace conventional counterparts in agricultural machines, ensuring their durability and performance.