No 2 (2018)

Articles

Topological optimization of the automobile bumper design under impact from the passive safety standpoint

Goncharov R.B., Zuzov V.N.

Abstract

Topological optimization of the elements of the automobile's design helps to reduce its weight while maintaining the strength and rigidity characteristics, therefore, the use of optimization in the design process is an important and urgent task. In this paper, topological optimization of the vehicle bumper is considered from the standpoint of passive safety. Brief theoretical information on the optimization method based on application of the method of hybrid cells and the concept of a body of variable density is given. The article presents the developed rational finite element models of the bumper and impactor for topological optimization, the loading scheme is described, the results with acceptable accuracy and minimum solution time using the LS-DYNA solver and the LS-TaSC module are obtained. The selection of the type and size of the finite elements for the solution of the problem of the shock interaction of the bumper and the impactor is substantiated by the example of three models of different degree of structuring. The variants of the initial and boundary conditions for topological optimization are considered. The substantiation of a choice of time of the decision of a problem of impact influence from the point of view of rational use of computer time and accuracy of received results is given. A variant of the design of the bumper and its finite element model is presented after the completion of the optimization results, and a check is made that the modified model satisfies the initial requirements. As a result, the weight of the modified bumper structure was 29% less than the original, while maintaining the stiffness and energy intensity parameters.
Izvestiya MGTU MAMI. 2018;(2):2-9
pages 2-9 views

The digital gauge of a tension of a belt of a gas-distributing mechanism and the generator in VAZ vehicles

Ermakov V.V., Maleev R.A., Holodov A.A., SHmatkov Y.M.

Abstract

In this article, the analysis of belt tension measurement instruments for the gas-distributing mechanism of automotive internal combustion engines is presented. The review and analysis of belt tension measurement instruments of the gas-distributing mechanism of leading foreign manufacturers was conducted. Classification of methods for measuring belt tension is carried out. It is concluded that the mechanical belt tension indicators do not provide sufficient measurement accuracy. The classification of electronic belt tensioners is considered. The main disadvantages of modern electronic measurement instruments of belt tension of the gas distribution mechanism of automobile internal combustion engines are revealed. A digital device for measuring the belt tension of the gas distribution mechanism of automotive internal combustion engines, developed at Togliatti Polytechnic University, is presented. Structural and schematic diagrams of the device for measuring belt tension, as well as working diagrams of the device, are given. The developed instrument is universal and can also be used to measure the tension of any belts, for example, for driving a car generator. The proposed method for measuring the tension of the gas-distributing belt and the generator can be further adapted to the use for motor vehicles of various automakers (including foreign ones) that are equipped, in particular, with electric start systems with a capacitive energy storage and a battery.
Izvestiya MGTU MAMI. 2018;(2):10-15
pages 10-15 views

Linear positioner based on pneumatic muscle

Efremova K.D., Pil'gunov V.N.

Abstract

The main goal of the work is to investigate the technical possibilities of creating a linear positioner on the basis of pneumatic muscle with acceptable characteristics for positioning. The experimental study of the power characteristics of the pneumatic muscle of the MAS 10-300 series of “FESTO” company is carried out. The physical essence of the cylindrical membrane operation is considered, on the basis of which the pneumatic muscle is constructed and a method for calculating the parameters of the positioning spring has been developed. It is shown that if the positional component is present in the load of pneumatic muscle then its rigidity (the dependence of the force on displacement) allows solving the task of positioning by controlling the pressure in the internal cavity of pneumatic muscle. If there is no positional component in the load or it is too small, then a positioning spring is needed to solve the positioning problem. Methods for determining the parameters of the positioning spring for positioners created on the basis of MAS pneumatic muscles of “FESTO” company are given. It has been established that the pneumatic muscle, which is used as a linear pneumatic motor, generates a pulling force which, with zero reduction of the pneumatic muscle, is 12 ... 14 times greater than the force developed on the return stroke by a pneumatic cylinder of equal working area of the piston and the specific force (force referred to the mass of the pneumatic motor) of pneumatic muscle is 100 times larger. This makes it possible to use pneumatic muscle as a loading device for brake, clamping and tensioning devices of transport systems and mobile units. To use the positioner in the tracking position control system, it must be provided with an analog feedback sensor. The static characteristic of the created physical layout of the positioner, obtained experimentally, has a quasilinear section in the range of the control pressure change of 2.5 ... 5 bar and agrees well with the calculation results. The nature of the transient process with respect to the input effect makes it possible to treat the positioner as an aperiodic link of the first order with a time constant T = 2 ... 5 s. As an example, the possibility of using a positioner in solving problems related to the need to stabilize a cargo platform in a horizontal position, in the case of a shift of the center of gravity of the cargo relative to the vertical axis of the platform, was investigated. The results of the work can be used and implemented in solving problems of linear and angular positioning of the load in flexible production systems, in executive devices of industrial robots, etc.
Izvestiya MGTU MAMI. 2018;(2):16-29
pages 16-29 views

Quasi-finite element model of rolling elastic wheels on uneven deformable substructure in nonlinear motion of a wheeled vehicle

Volskaja N.S., Zhileykin M.M., Zakharov A.J., Panshin M.V.

Abstract

One of the main directions of economic development of Russia was and should remain the accelerated development of the regions of the North and North-East, occupying more than 60% of the country. Further development of these areas requires new approaches and new technologies to solve transport and technological problems in the movement of goods and people in conditions where the roadway is off-road. At the same time, the movement of transport and technological machines is not only difficult, but in some cases completely excluded. The existing all-terrain vehicle equipment, made according to the old traditional schemes and commercially produced by the industry, does not meet the requirements that determine the efficiency and environmental friendliness of the engines of machines in complex natural and climatic conditions of operation. In this situation, the problem of forecasting the permeability of wheeled vehicles (KM) on the support surface with weak bearing properties is relevant. One of the main methods to predict permeability is a simulation of the motion of wheeled vehicles in different operating conditions, which are based on mathematical models of interaction between elastic tires with deformable irregularities of the support base. Currently in the theoretical study of the interaction of propellers with the ground formed two main directions: analytical method involving a mathematical description of the process under study and the finite element method based on computer simulation. The aim of this study is to develop a mathematical model of rolling elastic wheels on deformable rough reference base, taking into account the deformation of the contact patch at each end of the elementary playground. The mathematical model combines a mathematical description of the physical processes of interaction between elastic tires with uneven deformable substrates and finite element approach, based on consideration of processes in each end unit site of contact.
Izvestiya MGTU MAMI. 2018;(2):30-40
pages 30-40 views

Prospects for the use of automated and robotized electric drives on mobile energy equipment and agricultural machinery working bodies

Godzhaev Z.A., Izmajlov A.Y., Lachuga Y.F., SHogenov Y.H.

Abstract

The issues of application of electric drives (ED) on mobile energy and transport and technological agricultural means are actively discussed for the last 10-15 years in the agroengineering community. This is a very urgent and energy-efficient event for the further improvement of agricultural machinery. The urgency and importance of this work is related to the fact that it is also proposed to transfer active working bodies of agricultural machinery to ED. The various aspects related to the use of automated and robotic ED on agricultural machinery are considered in this paper. Various advantages of ED use have been identified - economic, ecological, technical, functional, etc. The design features of some existing mobile agricultural machines on automated ED have been analyzed, various layout electrical schemes such as the application of the Diesel-Generator system, autonomous power sources and hybrid power plants have been considered. Dynamics of development of technical and economic indicators of the component base used in automated ED such as-electric machines, converter equipment, storage batteries and etc. is given. Conceptual schemes of creation of basic mobile platforms based on automated ED have been substantiated which have two schemes of typical layouts: the application of the Diesel Generator system and the Autonomous Battery System, taking into account the functional and operational requirements for these mobile platforms. The main aspects of design, research and production of modern domestic automated ED’s, including problem aspects are revealed. In this article authors considered the prospects for using constructively and technologically advanced electrochemical energy sources such as fuel cells, as an energy installation for ED. The main strategic directions of creation and introduction of high-tech components for electric and hybrid-drive mobile equipment are revealed.
Izvestiya MGTU MAMI. 2018;(2):41-47
pages 41-47 views

Optimization of the working cycle of a transport diesel engine by simulating the combustion process with a double Wiebe function

Kamaltdinov V.G., Markov V.A., Lysov I.O., Popov A.E., Smolij A.E.

Abstract

For modeling the working cycle of transport diesels, models with two laws of combustion according to the Wiebe, mathematically related to each other and corresponding to the initial and main periods of the process, are increasingly being used. However, known mathematical models give different results in estimating the distribution of fuel shares between these periods. These models also do not allow to simulate a smooth start of the combustion process. Therefore, a new mathematical model was developed for calculating the working cycle of a diesel engine with two independent laws of combustion of fuel, described by the functions of Wiebe. Communication between them is carried out through a new parameter, which is the proportion of fuel, burning in the initial period, from the total cyclic feed. The novelty of the model is also the ability to set, within a wide range, independently of each other, the angles of the start and duration of the first and second combustion laws for the initial and base periods, respectively. A program for calculating the operating cycle with simulation of the combustion process using a new mathematical model is developed. Calculations have been made for a transport diesel engine equipped with a fuel-supply system of a battery type. The results of the calculation showed that an increase in the fraction of the fuel burned according to the first law from 0.1 to ~ 0.3 with other parameters being constant leads to a significant increase in the maximum pressure in the diesel cylinder and some improvement in the indicator indexes. With a further increase in the fuel fraction to 0.5, the maximum gas pressure continues to increase, and the indicator indexes slightly deteriorate. At the same time, in the initial period, the value of the index of the combustion character has practically no effect on the indicator index of the diesel engine and the maximum pressure in the cylinder. In the main period, the value of the indicator of the nature of combustion, on the contrary, significantly affects the indicator indexes of the diesel engine and the maximum pressure in the cylinder. The calculation determines the optimal heat release law in the diesel cylinder of ChN15/16 type, which provides the best indicator values when the maximum pressure in the cylinder is limited.
Izvestiya MGTU MAMI. 2018;(2):48-55
pages 48-55 views

Influence of the elements of the spatial bearing system of the vehicle of increased cross-country ability of the “buggy” class on the parameters of its stress-strain state

Bazhenov E.E., Bujnachev S.K., Kustovskij A.N.

Abstract

The technique of the analysis of a degree of influence of separate elements of a tubular bearing structure of the buggy vehicle on parameters of its stress-strain condition is studied in the paper. As parameters of the stress-strain state the angle of twisting of the frame around the longitudinal axis of symmetry, as well as the stress in the front upper corners of the cockpit (the subconstruction where the racer is located), were selected. The considered method is based on the regression analysis, with the help of which the equations for calculating the above values were obtained. Due to the volume of data and the associated difficulties with subsequent analysis, the given equations are proposed to be used only for the most important elements of the individual frame sub-structures from the point of view of the engineer. The definition of such elements can depend on the experience of the engineer, his intuition, and also on the basis of the previously accumulated third-party information. The object of the study is the frame of the “buggy” cross-country vehicle used for movement on rough terrain, in particular, in forestry by huntsmen. The calculations were carried out in the SolidWorks computer simulation program using the finite element method.
Izvestiya MGTU MAMI. 2018;(2):56-61
pages 56-61 views

Determination of the time and the path of acceleration of a vehicle equipped with a gearbox without switching-off of the power flow

Ryabev A.V., Parfenov A.P.

Abstract

Gearbox with gears switching without switching-off of the power flow (GWSPF) are known to spread on agricultural tractors, which have a large number of gears to support various technological processes. However, the expediency of using them on high-speed crawler machines (HSCM), which has the limited number of gears, is not obvious due to greater complexity and cost, as well as additional power losses compared to the widely used simpler mechanical gearboxes. For HSCM, as well as vehicles with a number of gears of more than five, the advantages of shifting without breaking the power flow can outweigh their disadvantages mentioned above. For army crawler machines used in military conditions the time and the path of dispersal can be decisive. The paper gives a comparative evaluation of HSCM equipped with a five-speed mechanical synchronized gearbox and GWSPF, which showed the advantages of gear shift without breaking the power flow in reducing the time and acceleration path by 1.3 and 1.2 times, respectively. To perform the calculations, a technique and algorithm for calculating the parameters of the acceleration of the machine was developed in comparison with the approximate method of graph-analytic integration of professor N. Yakovlev. The exact calculation technique is based on solving a differential equation relating the acceleration to the speeding up parameters of the crawler machines under the initial conditions corresponding to the beginning of its motion. The methodology and calculation algorithm can also be used to determine the traction-speed and fuel-economic qualities of other vehicles, including automobiles.
Izvestiya MGTU MAMI. 2018;(2):62-70
pages 62-70 views

Mathematical model for assessing the influence of a coupled suspension system on the smooth running of a tracked vehicle

Sarach E.B., Cipilev A.A., Kurasova M.S.

Abstract

This article is devoted to the solution of the actual problem - the development of an imitative mathematical model for the investigation of the smooth running of a caterpillar vehicle with a coupled suspension system. The publication is an analysis of the merits and demerits of existing mathematical models, allowing to evaluate the feasibility of certain constructive solutions at the design stage. In order to take into account the links in the suspension system and to assess the possibility of using the obtained mathematical model to study the smoothness of the progress of vehicles with a coupled suspension system, the authors finalized the mathematical model of rectilinear motion created by staff of Bauman Moscow State Technical University. The simulation was carried out in the MATLAB Simulink software package. The results of the work of the simulation mathematical model of the coupled suspension system are demonstrated on the example of solving an applied problem: comparison of the smoothness of the track of a caterpillar vehicle with a coupled and independent suspension system. It is shown that the presence of bonds in the suspension system introduced to reduce loads on the chassis elements does not affect the smoothness of the track of the caterpillar machine. The height of the periodic irregularities that the vehicle can overcome without “disruption” of the suspension in the entire speed range for both versions of the suspension system is 0.23 m. This corresponds to the level of modern high-speed crawler vehicles. Thus, the modified simulation mathematical model allows to investigate the smoothness of the transport vehicles with the coupled suspension system.
Izvestiya MGTU MAMI. 2018;(2):71-79
pages 71-79 views

One-dimensional univariate work simulation of turbocharged engine with restrictor before compressor inlet

Tatarov M.G.

Abstract

All over the world, and in Russia, especially, the engineering sports competitions "Formula Student" are gaining popularity. Formula Student - is an international competition held among students of technical universities, in order to get practical knowledge in the process of developing and building a Formula student class racecar. When creating a car, you must adhere to strict technical regulations. So, one of the limitations is the maximum engine capacity - 710 cubic meters, which, in itself, implies the use of a motorcycle engine. A mandatory condition is the presence of a restrictive nozzle (restrictor) which have 20 mm diameter and placing in the inlet system. This causes many problems when designing engine intake systems. However, it allowed using various systems of pressurization of engines. The most common and effective is the installation of the turbocharger. This helps to solve the problem of insufficient amount of air that entering to the engine. Moreover, with the correct configuration of all components of the intake system in combination with the turbocharger, it is possible to achieve power and torque exceeding the standard engine without a restrictive nozzle. The article presents the data obtained in the course of a one-dimensional simulation of the KTM LC4 engine with a turbocharger and a restrictor in the intake manifold. The purpose of the work is to reduce the negative influence of the restrictor on the power and torque parameters of the KTM LC4 engine by using a turbocharger. In the course of the work, an analysis was made of gas-dynamic processes occurring in various parts of the engine intake system that affect its output values based on numerical studies. Because of the research, the dependences of the output parameters of the engine (maximum power and maximum torque) on the parameters, shapes and sizes of various components of the intake system with a turbocharger.
Izvestiya MGTU MAMI. 2018;(2):80-87
pages 80-87 views

Investigation of internal dynamics of a two-piston air-hydraulic spring

Cipilev A.A., ZHarov S.S.

Abstract

With the development of electronic computers the possibility of investigating the work of various devices and mechanisms has reached a qualitatively new level. The speed of modern computers makes it possible to carry out investigations of the internal dynamics of various units and assemblies of high-speed caterpillar machines, in particular, suspension systems, taking into account the most subtle and complex nuances of their work. The present article is devoted to the investigation of the internal dynamics of the operation of a pneumohydraulic spring fitted with an embedded piston that allows stabilizing the value of the static course of the suspension in a wide range of temperatures. The introduction outlines the relevance of the use of pneumohydraulic suspension systems and the prospects for their application in order to increase the smoothness indicators required for machines with high power-to-weight ratio. However, along with the prospects due to the well-known advantages of such suspension systems, there are also disadvantages, in particular, instability of the characteristics of the gas when its temperature changes. The need to stabilize the static course has led to the appearance of various versions of the pneumohydraulic springs (PS), in particular, the PS with the embedded piston. However, the experience of using machines with such a configuration of the PS testifies to a violation of the stability of the static stroke. The paper investigates the operation of the PS under various loading conditions and various temperatures and shows the conditions for the appearance of the phenomenon of spontaneous change in the course of the roller. It is shown that simultaneous stabilization of the stroke at high and low temperatures is impossible and, in addition, the stabilization of the static path at low temperatures will lead to a shock motion of the embedded piston, accompanied by the transfer of high accelerations to the sprung body. The article concludes with recommendations on the choice of the rational position of the static stroke of the rod on the static elastic characteristic of PS.
Izvestiya MGTU MAMI. 2018;(2):88-99
pages 88-99 views

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