卷 15, 编号 1 (2021)

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Articles

Vibration levels on operator’s workplace and vibration protection characteristics of seat suspensions

Godzhayev Z., Lyashenko M., Shekhovtsov V., Potapov P., Iskaliyev A.

摘要

This article analyzes the nature and parameters of the main operational disturbances, which energy is directly or indirectly transferred to the operator's workplace of tractor with a caterpillar or wheeled propeller when performing various technological operations, based on experimental research data. The main operating frequency range of these operational disturbances is considered. The contribution of each frequency component to the overall level of vibration at the operator's workplace is assessed. The example of implementation the results of field measurements of real operational disturbances and vibration characteristics on a K-744R1 (st.) wheeled tractor, which operated in a unit with a PG-3-5 plane cutter in the mode of plowing stubble at a constant speed of movement was used. The comparative study of vibration-protective properties of various designs of seat suspension was carried out. The technique of field measurements, including specialized equipment of the ZETLAB and Assistant companies, the mode, the sensor installation scheme and other conditions are described. Using the numerical Runge-Kutta method and mathematical modeling tools in the Simulink MatLab software environment, the operation of the serial suspension of the K-744R1 (st.) tractor seat, air suspension of the Sibeco seat with a scissor guiding mechanism and the innovative air suspension of the seat (based on Sibeco) with controlled extraction of vibration energy and its subsequent recuperation was simulated. There were obtained the calculated oscillograms and spectra of vertical accelerations on a seat cushion, sprung with each of the considered suspensions under the input action of measured real operational disturbances. The results of the analysis of the research results are summed up.
Izvestiya MGTU MAMI. 2021;15(1):2-11
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Improving the efficiency and safety of operation of underground tunnel escalators. Forecasting model

Popov V., Yelantsev V.

摘要

The subways of Moscow and St. Petersburg are the oldest in Russia. Its infrastructure includes a diverse fleet of equipment. The fleet of rolling stock in the last decade was mainly renewed, while due to the peculiarities of operation and mainly for financial reasons, the escalator fleet will not be replaced for a long time. In this connection, the main task of the departments responsible for the operation of escalators is to maintain the rapidly aging fleet in good condition. Thus, a situation, when the escalator economy is a source of costs to meet the constantly increasing demand for resources is formed. At the same time, the limited allocation of all types of resources only aggravates the current situation. The above circumstances contribute to the actualization of the issue of selection of tools, which makes it possible to increase the efficiency and safety of operation of underground tunnel escalators. According to the authors of the paper, one of such tools can be the forecasting of the technical state of the elements of the escalator subsystems, made on the basis of special routing of information flows, designed for the optimal distribution of allocated resources. Since an escalator is a complex technical object of increased danger, the routing of information flows for it characterizing its technical condition is possible only on the basis of a preliminary decomposition into information levels. For this reason, the beginning of the paper is devoted to the decomposition of the technical state of the escalator into four information levels, covering all aspects of the technical state from the micro-level of the state of materials from which the elements of the escalator subsystems are made, ending with the functional state of the entire escalator. The purpose of the work is further revealed. It consists in describing a general mathematical model for predicting the technical state of the elements of the escalator subsystems and the requirements for its construction. The work describes the main task that solves the proposed forecast model. In conclusion, the options for using the proposed model are considered. The scientific novelty of the proposed approach lies in the use of the modern mathematical apparatus of the fuzzy set theory for processing parametric information, elements of artificial intelligence, as well as a precedent approach in analyzing the operational situation, which, in combination, are necessary to build a predictive model of the technical state as applied to the escalator facilities of the subway. From a practical point of view, it should be noted that the proposed mathematical model, implemented on the basis of modern information technologies, will make it possible to more rationally adjust the mechanisms for allocating resources, while ensuring the necessary level of safety for passenger transportation.
Izvestiya MGTU MAMI. 2021;15(1):12-22
pages 12-22 views
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Calculation of wind turbine generator power characteristics using Windpowerlib software module

Ilichev V., Shevelev D.

摘要

The problem of using alternative energy sources is becoming more and more urgent every year. Wind turbogenerators are one of the most promising alternative power plants. The article is devoted to the creation and testing of a calculation program for determining the main indicators of wind generators - the dependence of the power factor (efficiency) and the generated power on wind speed, the power change curve by time intervals, and the average power per year. At the beginning of the work, basic information is given about alternative power plants, in particular, about wind generators, their advantages, disadvantages and methods of feasibility study for use in a given area according to weather statistics. The following are the modules used in the program, the main of which is a special command library for calculating wind turbines Windpowerlib. The sequence of implementation of the calculation algorithm stages is described: methods of entering weather data and the main characteristics of the turbine, the procedure for calculating the power of the turbine generator, and the output of results in the form of qualitatively formalized graphs. To test the developed program, the energy characteristics of one of the most common and widely used wind generators in the world were calculated - the Siemens SWT 3.6-120 model, the calculation results were compared with operational data published by the manufacturer of this plant. The graphs proved a high degree of conformity between the calculated and actual characteristics. The plant capacity change during the year is determined by hourly time intervals, as well as the average capacity generated per year. The resulting software product allows the end user to easily download input data and automatically calculate all the above characteristics of any wind turbine. In conclusion, conclusions were drawn on the work done, recommendations were made to expand the scope of the methodology to determine the characteristics of other power plants. The planned direction of further research in this area using the developed software product is indicated.

Izvestiya MGTU MAMI. 2021;15(1):23-31
pages 23-31 views
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Calculation of the coefficient of local hydraulic diaphragm resistance in transitional and laminar areas of flow

Kondratyev A., Ogorodnik K., Frikha M.

摘要

In the case of hydraulic machines and devices, local hydraulic resistances, as a rule, constitute the determining part of the total head losses during the operation of any hydraulic machine. The most detailed reference book, which has gone through many editions in our country and published abroad, is the “Reference book on hydraulic resistance” by I.E. Idelchik. At the same time, the analysis carried out in the cited literature showed that, depending on the year of publication of the reference book by I.E. Idelchik, for the same local resistance, the difference in the numerical values of the same local hydraulic resistance can reach a multiplicity. The purpose of this work is to analyze the recommendations given in the handbook for calculating the hydraulic resistance coefficient of diaphragms (holes) with any edge shapes for various conditions of flow overflow in the transition and laminar regions inside a pipeline of constant cross-section. In particular, it is shown that tabular values are recommended for calculating the filling factor of the diaphragm section and an analytical dependence is given, the differences in the numerical values of which reach 15%, which introduces uncertainty in the results of specific calculations. To a much greater extent, a similar situation takes place when using the recommendations for calculating the coefficient of hydraulic resistance. In this case, also, the given numerical tabular values of the coefficients of hydraulic friction resistance when the flow passes through the hole and calculated from the given analytical dependence, differ in multiplicity, which indicates the absence of a connection between them. This issue requires further special consideration.
Izvestiya MGTU MAMI. 2021;15(1):32-37
pages 32-37 views
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Method for determining the temperature fields of the spark plug

Yakhutl' D., Maleyev R., Zuyev S., Shmatkov Y., Ryabykh Y.

摘要

This article examines the main factors that determine the thermal performance of a spark plug in the temperature range from 300 to 2500 Kelvin. The optimal value of the temperature of the heat cone was determined. A technique and algorithms for the numerical simulation of the thermal state of a spark plug are presented. These made it possible to calculate the dependence of the thermal conductivity coefficient of ceramic elements of a plug and the specific heat capacity of ceramic insulator on temperature. The calculation of the working cycle in the engine cylinder was carried out. The calculation of the temperature distribution of heat fluxes in the elements of the spark plug design was performed.

The assessment of the thermal characteristics of the spark plug is carried out by the method of numerical modeling of the operating cycle of an internal combustion engine. The calculation of the instantaneous temperature distribution in the body of the spark plug and on its surface is carried out. Calculations of the intensity of heat fluxes between the spark plugs and adjacent parts of the working fluid were carried out.

The modeling of the operating cycle for various operating modes of the engine was made. The temperature fields of the spark plugs were determined. An array of initial data for calculating the temperature fields of the spark plug was formed. Dependences of the temperature of the working fluid in the vicinity of the spark plug on the angle of rotation of the crankshaft are determined. The harmonic components of the heat transfer coefficients between the working fluid and the cylinder fire guard (Voshni coefficient) are considered. The harmonic components of the heat flux density are considered. Calculations of the heat field of the spark plug are carried out for various operating modes of the engine, using the finite element method. The calculation of the temperature field of the spark plug by the finite element method was carried out using ANSYS, SolidWorks, Inventor, etc.

Izvestiya MGTU MAMI. 2021;15(1):46-53
pages 46-53 views
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Numerical simulation of dynamic processes in transmission of vehicle

Hoodorozhkov S., Krasilnikov A.

摘要

The article considers the issues of digital modeling of dynamic processes in the transmissions of transport vehicles. The purpose of this research was to develop an algorithm for numerical mathematical modeling of dynamic processes in the transmissions of transport vehicles using modern digital software packages. The method includes a systematic approach to the study of dynamic processes during switching, based on modeling the operation of the gearbox together with the internal combustion engine (taking into account its dynamic, speed and load characteristics). The order of application of the MATLab – Simulink, Simscape software packages for numerical simulation of dynamic processes is considered. Using the fundamental blocks of these applications, models of physical components are created: the internal combustion engine, friction clutches, gearboxes, elastic shafts, damping devices, and tractor power transmission control systems. A digital model of the tractor transmission is created, its design scheme is given, and the initial characteristics are set. It was used to simulate dynamic processes in the tractor gearbox. The main attention in this paper is paid to the application of the proposed method for calculating the dynamic processes in the gearbox during gear changes under load with forward and reverse switching, including the simultaneous use of several friction clutches.

Izvestiya MGTU MAMI. 2021;15(1):38-45
pages 38-45 views
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Investigation of the environmental characteristics of a diesel engine when operating on activated fuel

Plotnikov S., Kartashevich A., Motovilova M.

摘要

The internal combustion engine is the most widespread source of energy for vehicles. The main requirements for an internal combustion engine include: the efficiency of functioning as part of a vehicle, high performance indicators, as well as environmental parameters of the emission of exhaust gases into the environment. The fulfillment of these conditions is possible by improving the design of the engine, as well as improving the working process of the diesel engine while increasing the quality of diesel fuel or additional impact directly on the fuel itself. One of the most effective ways to influence diesel fuel is to transfer a certain amount of heat to it in the high-pressure fuel line in front of the injectors. At the same time, the physical and mechanical properties of diesel fuel change, which leads to a change in mixture formation and the combustion process in the engine cylinder. To intensify the combustion process, a method of preliminary high-temperature local heating of diesel fuel in the fuel supply system in front of the injectors was proposed. To achieve this goal, several main directions were identified, including the study of environmental indicators during the intensification of the combustion process. The tests were carried out in stages. At the first stage, the operation of the fuel injector when operating on activated fuel (bench, laboratory tests) was investigated. At the next stage, the indicators of the diesel engine in the main modes of its operation were investigated. Bench (laboratory) tests made it possible to draw a conclusion about the operability and compliance of the aggregate with the technical requirements of the manufacturer and the parameters of GOST. The bench tests proved the possibility of a diesel engine running on activated fuel without deteriorating environmental performance in the exhaust gases; at the same time, changes in the toxicity and smoke of the exhaust gases from different values of the average effective pressure were revealed.
Izvestiya MGTU MAMI. 2021;15(1):54-62
pages 54-62 views
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Modern approach to testing and validation of driver assistance systems

Toropov Y., Trusov Y., Vashurin A., Moshkov P.

摘要

The ever-increasing demands of vehicle safety are forcing car manufacturers to develop ADAS systems (“intelligent assistants”). However, before starting sales of car equipped with such functions it is necessary to fully test and validate the algorithms for the operation of electronic systems in various conditions. Currently, the most popular methods for debugging and testing ADAS systems are based on "model-”, “software-" and "hardware-in-the-loop" modelling, which allows developers to identify and eliminate errors in the early stages of product development, thus saving money. Despite the enormous advantages of simulation, full-scale tests remain the fundamental and final stage before the start of mass production, this is due to the fact that international and Russia government standards currently don’t provide for the certification of “electronic assistants” through virtual tests. In this regard, manufacturers of measuring equipment and test-engineers are faced with the task of developing a new test setup that provides fixing the GNSS-position of vehicles in dynamic modes with centimeter accuracy, as well as making synchronized video recording. This article describes the approach of the employees of the NNTU n.a. R. E. Alekseev to the solution of this problem: the design of the concept and its implementation on a light commercial vehicle with ADAS systems. To fix coordinates with centimeter accuracy we have used Racelogic Vbox 100 Hz, operating in the RTK-mode, synchronized video recording was made using Racelogic Video Vbox Pro, which includes 4 wide-angle cameras. The approbation of the measuring installation was carried out when testing the following systems: a blind spot detector, a lane departure warning and a parking space search assistant. The article presents a number of graphs of the functioning of one of the systems.
Izvestiya MGTU MAMI. 2021;15(1):63-72
pages 63-72 views
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Numerical study of the effect of droplet coagulation intensity on polydisperse aerosol fraction distribution

Tukmakov D.

摘要

The paper is devoted to the study of the effect of the intensity of aerosol fluctuations on the distribution of fractions of the dispersed component of the coagulating aerosol. Oscillations of aerosol in closed channel are numerically modeled in operation. To describe the dynamics of the carrier medium, a two-dimensional non-stationary system of Navier-Stokes equations for compressed gas is used. They are written taking into account interfacial power interaction and interfacial heat exchange. To describe the dynamics of the dispersed phase, a system of equations is solved for each of its fractions. It includes an equation of continuity for the “average density” of the fraction, equations of preservation of spatial components of the pulse and an equation of preservation of thermal energy of the fraction of the dispersed phase of the gas suspension. Phase-to-phase power interaction included Archimedes force, attached mass force, and aerodynamic drag force. Heat exchange between the carrier medium-gas and each of the fractions of the dispersed phase was also taken into account. The mathematical model of dynamics of polydisperse aerosol was supplemented by the mathematical model of collision coagulation of aerosol. For the velocity components of the mixture, uniform Dirichlet boundary conditions were set. For the remaining functions of the dynamics of the multiphase mixture, uniform Neumann boundary conditions were set. The equations were solved by the explicit McCormack method with a nonlinear correction scheme that allows to obtain a monotone solution. As a result of numerical calculations, it was determined that in the vicinity of the oscillating piston, an area with an increased content of coarse particles is formed. The coagulation process results in a monotonous increase in volume content of the coarse particle fraction and a monotonous decrease in volume content of fine particles. Increasing the intensity of gas fluctuations leads to intensification of the process of coagulation of aerosol droplets.
Izvestiya MGTU MAMI. 2021;15(1):73-80
pages 73-80 views
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Topological optimization of the roof structure of a passenger car in order to increase energy intensity in a side impact

Sulegin D., Zuzov V.

摘要

This article considered the main issues of finding options for strengthening the roofing of the vehicle body based on topological optimization in order to meet the requirements of passive safety with a minimum mass. The method for achieving this goal was mathematical modeling using the Topology Optimization modules of the ANSYS software package and the explicit dynamics of LS-Dyna. In order to test the effectiveness of the reinforcements, the pillar side impact according to UNECE 135 “Uniform provisions concerning the approval of vehicles with regard to their performance in side impact on a pillar” was selected as the loading mode. The efficiency criterion was the energy intensity of the body, defined as the ratio of the energy of the system to the residual (plastic) deformation at the level of the center of the door. Based on the topological optimization, two variants of the arrangement of the reinforcing elements, practically equivalent in efficiency, were obtained. For the most complete assessment of the influence of the parameters, several options for strengthening the roofing were considered: placement of steel reinforcing elements; placement of foam aluminum under the roof; combination of steel elements with filling their cavities with foam aluminum. Based on the simulation results, a comparative assessment of the effectiveness of the considered amplification options was carried out. The most effective were the options for reinforcing the roofing with channel-shaped beams and filling them with foam and the option for reinforcing the roofing with channel-shaped beams and diagonal bridges in them, causing it to increase compared to the original structure by 20.88 and 19.94%, respectively, but at the same time the mass of the first option is 42 kg less than the mass of the second.
Izvestiya MGTU MAMI. 2021;15(1):81-88
pages 81-88 views
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Mathematical modeling of a system for monitoring the insulation resistance of a high-voltage power grid of a hybrid vehicle

Malyshev A., Grunenkov Y., Debelov V., Kozlovskiy V., Shishkov A.

摘要

The paper presents mathematical models and computational and analytical dependences, which make it possible to implement a system for monitoring the insulation resistance of a high-voltage power grid of a hybrid vehicle and make it possible to formulate requirements for the physical and simulation model of the software and hardware complex of laboratory tests. The purpose of the work is to determine the main functions and characteristics of the insulation monitoring system, its features, the principle of operation and methods of monitoring the insulation resistance, drawing up requirements for the simulation system. The introduction justifies the importance of monitoring insulation resistance and provides references to standards that regulate the requirements for the measurement and determination of mains failure. The block diagram of the vehicle power supply and the role of the insulation resistance monitoring system in this diagram are presented, the features of insulation monitoring are explained. The principle of operation of the insulation monitoring system and the use of the most common schemes are considered. The calculated dependencies for each of the presented schemes are given. These allow calculating the insulation resistance. The procedure for measuring the insulation resistance according to the ISO standard is described and the corresponding equations are given. For the presented circuit, a graph that explains the principle of the system's operation, when one of the keys is closed, the voltage across the measuring resistor changes with the normal insulation state of the positive and negative power supply bus of the high-voltage system is given. The conclusions provide a generalization of the presented mathematical model and formulate the requirements for the software and hardware complex, which allows simulation and mathematical modeling of electrical systems and their components in various operating modes. The paper explains the features of the software and hardware complex that allows to simulate changes in the insulation resistance and faults of the high-voltage power supply network for a vehicle with a hybrid power plant.
Izvestiya MGTU MAMI. 2021;15(1):89-98
pages 89-98 views
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