Випуск 55

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Application of the partial accelerations method in large-scale modeling of mechanical systems
(Харківський національний автомобільно-дорожній університет, 2024) Bogomolov, V.; Podrigalo, M.; Shein, V.; Baitsur, M.; Богомолов, В. О.; Подригало, М. А.; Шеїн, В. С.; Байцур, М. В.
Problem. Modern trends in the design of mechanical systems require the application of efficient methods to reduce time and resource expenditures during the development and testing of new structures. Large-scale modeling serves as a critical tool for verifying theoretical principles, evaluating the safety, and assessing the functionality of mechanical systems at early design stages. However, the complexity of dynamic models that describe the behavior of mobile machines in a scaled format necessitates the development of approaches to simplify such models. One promising approach is the method of partial accelerations, which enables mathematical and computational optimization of modeling processes. Purpose. The purpose of this study is to improve large-scale modeling methods by employing the method of partial accelerations in the study of mobile machine dynamics. Methodology. The research is based on the principle of superposition in mechanics, which enables the replacement of classical dynamic equations with equations of partial accelerations in a homogeneous vector space. This approach significantly simplifies the mathematical representation of system dynamics. Results. It has been established that the acceleration scale for mechanical systems operating within Earth’s gravitational field is always equal to unity, simplifying the process of determining the scaling factors for other physical quantities. The study proposes equations for partial accelerations that provide an accurate representation of the kinematics of both prototype and scaled models of mobile machines. Furthermore, the application of the multi-component complex motion model demonstrated its ability to evaluate dynamic deviations in mobile machines and account for the effects of active and reactive forces. Originality. The proposed method of partial accelerations introduces a novel approach to large-scale modeling of mechanical systems. By operating within a homogeneous vector space of accelerations, this method eliminates the need for inertial forces, reducing the complexity of mathematical models and enhancing the accuracy of predicting system dynamic behavior. Practical meaning. The method of partial accelerations can be applied in the following areas: designing mobile machines, including vehicles and planetary rovers; optimizing dynamic tests using accelerometers; modeling the energy efficiency of vehicles under steady and unsteady motion; enhancing scaled models for safety and maneuverability analyses.
Cycle mechanical coefficient of useful effect of motor-transmission installations of transportation and tractor vehicles
(Харківський національний автомобільно-дорожній університет, 2024) Podrigalo, M.; Podrigalo, N.; Vakhniuk, S.; Bisha, V.; Подригало, М. А.; Подригало, Н. М.; Вахнюк, С. А.; Біша, В. М.
Problem. When determining the efficiency coefficient of the motor-transmission systems of cars and tractors, it is necessary to consider not only the losses due to viscous and dry friction but also the losses caused by the circulation of potential and kinetic energy within the transmission. These losses result from the use of typical internal combustion engines in motor-transmission systems. Currently, existing studies do not take into account the dynamic cyclic energy losses in the transmission, which prevents an accurate assessment of the cyclic efficiency coefficient. Purpose. The purpose is to determine the cyclic efficiency coefficient of motor-transmission systems with internal combustion engines, taking into account the cyclic dynamic efficiency coefficient of the transmission in vehicles equipped with internal combustion engines. Methodology. The approaches adopted in this work to achieve the stated goal are based on the theoretical foundations for determining the dynamic efficiency coefficient, the work balance in the motor-transmission system of a car (or tractor) over one oscillation period of the indicator torque and the angular velocities of the engine's crankshaft during one oscillation period of its torque. Results. The cyclic mechanical efficiency coefficient of motor-transmission systems in wheeled machines has been determined, accounting for the losses associated with the acceleration of moving masses and the torque irregularities inherent to internal combustion engines. A relationship has been established in which the cyclic coefficients of dynamic and elastic losses are equal to zero when the torque irregularity coefficient is zero, a characteristic typical of electric motors. Originality. The results of the study provide a general understanding of the proportionality of the cyclic dynamic coefficient of mechanical losses in the transmission to the torque irregularity coefficient and the difference between the squares of the circular frequencies of torque oscillations and the natural (free) oscillations of the transmission input shaft. Practical meaning. The obtained results can be recommended for identifying frequency coincidences that lead to resonance, where the cyclic coefficients of elastic and dynamic losses increase sharply.
Experimental study of the influence of the damping coefficient of a semi-active suspension on vehicle acceleration during starting
(Харківський національний автомобільно-дорожній університет, 2024) Shuklinov, S.; Tkachov, О.; Шуклінов, С. М.; Ткачов, О. Ю.
Problem. The influence of the damping coefficient of a semi-active suspension on vehicle acceleration during starting can be determined experimentally. The experimental research method is the most accurate for obtaining real data, as it accounts for vehicle parameters and the specific operation of the suspension system. This study conducted an experimental investigation of the acceleration process of a vehicle equipped with a semi-active suspension. The effect of the suspension damping coefficient on vehicle acceleration was determined for the first and second gears. The vehicle selected for the study was a Land Rover Evoque equipped with a CVSA suspension system from Tenneco. Speed, acceleration, and distance parameters of the vehicle were measured under conditions of low and high suspension damping. For a clear representation of the research results, graphical dependencies of speed, acceleration, and distance on time were constructed using MATLAB software. The results were analyzed, and corresponding conclusions were drawn. Goal. The purpose of the study is to validate the theoretical research on the influence of the damping coefficient of a semi-active suspension on vehicle acceleration during starting under road conditions. Methodology. The approaches adopted in this study to achieve the objective are based on the principles of vehicle theory. Results. It has been established that a vehicle with a high suspension damping coefficient has a greater impact on acceleration in first and second gears compared to a vehicle with a low damping coefficient. It was determined that the acceleration of a vehicle with high suspension damping during first-gear acceleration is higher than that of a vehicle with low damping. During the shift from first to second gear, the suspension settings do not affect vehicle acceleration. In second-gear acceleration, the vehicle with high suspension damping also exhibits higher acceleration than with low damping. Corresponding data were obtained showing different acceleration distances for vehicles with high and low suspension damping over the same period of time. Originality. The results of the study provided an insight into the impact of suspension on vehicle acceleration when using different gears. Practical value. The results of the experimental study enable a comparative analysis of the theoretical research on the influence of the damping coefficient on vehicle acceleration. Moreover, the obtained data can be utilized in the design of new vehicles or in the improvement of sports cars, such as dragsters.
Maneuverability and off-road capability of a four-axle vehicle with swivel bogies and electrically driven wheels
(Харківський національний автомобільно-дорожній університет, 2024) Yeremenko, A.; Smetanin, G.; Єременко, А. В.; Сметанін, Г. В.
Problem. The issues of maneuverability and off-road capability in four-axle vehicles involve ensuring their efficient operation on rough terrain, in narrow or confined spaces, and under challenging operating conditions. Key challenges include reducing the turning radius, achieving even load distribution across axles, and minimizing energy losses during movement. Additionally, it is crucial to ensure the reliable performance of all drivetrain components, particularly under increased wear and exposure to external factors. Goal. The objective of the study is to develop and substantiate technical solutions aimed at improving the maneuverability and off-road capability of four-axle vehicles by optimizing the design of the running gear, implementing innovative drives, and enhancing the control system. This will ensure the efficient operation of vehicles under challenging conditions, improve their energy efficiency and reliability, and expand the scope of their applications. Methodology. The methodology for implementing the maneuverability and off-road capability of a four-axle vehicle with swiveling bogies and electric wheel drive includes the analysis and modeling of the vehicle's reaction to various operating conditions, as well as optimizing the drive and control systems to ensure high movement efficiency on challenging routes. Results. The results of the research on the maneuverability and off-road capability of a four-axle vehicle with swiveling bogies and electric wheel drive have improved the turning efficiency of such a vehicle on challenging terrain with steep slopes and uneven areas without road coverage. By optimizing the design of the bogies and implementing electric wheel drives, it was possible to reduce the weight and geometric parameters of the vehicle, allowing for more precise maneuvers in confined spaces while maintaining stable movement with sufficiently high off-road capability and aneuverability of the four-axle vehicle. Originality. The originality of the research lies in the comprehensive approach to improving the maneuverability and off-road capability of a four-axle vehicle with swiveling bogies and electric wheel drive. For the first time, innovative methods for optimizing the design of the running gear and implementing electric drives were applied, which significantly reduced energy losses and improved motion control on challenging terrain. New approaches to modeling movement ensured high maneuvering efficiency under various operating conditions. These results provide new opportunities for the application of such vehicles in specialized industries where the requirements for off-road capability and maneuverability are extremely high. Practical value. The practical significance of the research lies in the potential implementation of the developed technical solutions in the production of four-axle vehicles for operation in challenging conditions, such as construction, agriculture, and military applications. The improvements developed allow for enhanced equipment efficiency, reduced energy consumption, and high maneuverability and off-road capability on difficult routes.
Modeling of limitations on the use of hydraulic motor-wheels in transmissions of mobile machines
(Харківський національний автомобільно-дорожній університет, 2024) Avrunin, G.; Podrigalo, M.; Podrigalo, N.; Fidrovskaya, N.; Moroz, I.; Yatsunskyi, P.; Аврунін, Г. А.; Подригало, М. А.; Подригало, Н. М.; Фідровська, Н. М.; Мороз, І. І.; Яцунський, П. П.
Problem. The development of mobile machines with increased movement speeds requires constructive solutions for the creation of appropriate transmissions, particularly the analysis of the possibility of creating hydraulic stepless transmissions using hydraulic motors of various types. Goal. Increasing the technical level of transmissions of utility, construction and road vehicles and multi-axle high-speed vehicles with the help of advances in modern hydrostatic transmissions. Methodology. The transmissions of mobile machines are considered from the point of view of the possibility of using multi-cycle radial-piston hydraulic motors in them as gearless hydraulic motor-wheels. According to the traction-speed characteristics, the values of the torques and rotation frequencies of the hubs were calculated, and the hydraulic motor-wheels were selected according to the corresponding working volumes. As an example, calculations of the dynamics of the hydraulic drive transmission of a cleaning utility vehicle were carried out using the VisSim application program package, where the universal characteristic of the gerotor hydraulic motor was used to determine the hydromechanical efficiency in the modes from displacement to maximum rotation frequency. The results. Positive results were obtained in terms of increasing the speed of mobile machines when using hydraulic motor-wheels of radial piston multicycle action in transmissions instead of gerotor hydraulic motors, axial-piston hydraulic motors with planetary gearboxes, hydraulic transmissions with cardan shafts and mechanical transmissions. Originality. New calculated data on the initial characteristics of transmissions with a hydraulic drive were obtained, the possibilities of modeling dynamic processes in the transmission hydraulic drive depending on the action of external factors regarding the load, speed and properties of the working fluid were shown. It was established that for multi-axle vehicles with a maximum speed of up to 100 km/h, the use of electric or hydraulic motor-wheels requires the addition of planetary gearboxes with reducers or multiplier frames. Practical meaning. Recommendations for the use of radial-piston gearless hydraulic motor-wheels in mobile machines in order to improve their technical level are given.
Загальні відомості про збірку
(Харківський національний автомобільно-дорожній університет, 2024)

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