The Problem of Damping the Transverse Oscillations on a Longitudinally Moving String

Introduction. The problem under consideration is relevant to production processes associated with the longitudinal movement of materials, for example, for producing paper webs. For these processes transverse disturbances, which in the vertical section are described by the hyperbolic equation of a longitudinally moving string, are extremely undesirable. That gives the problem of damping these oscillations within a finite time. Materials and Methods. To solve the problem of damping the oscillations, the authors suggest reducing it to the trigonometric problem of the moments at an arbitrary time interval. When considering moving materials, the construction of the basis systems forming the moment problem is a special challenge, since the hyperbolic equation contains a mixed derivative (Coriolis acceleration). Therefore, the classical method of separating variables is not applicable in this case. Instead, a new method is used to find self-similar solutions of non-stationary equations, which makes it possible to find the basis systems explicitly. Results. In the case of paper web, it is necessary to find a minimal in the whole class of admissible perturbations time interval, within which the trigonometric system forming the problem of moments is the Riesz basis, that make it possible through using the system conjugate with it to find the optimal control way in the form of a series and, therefore, to build a so-called optimal damper. Conclusions. As a result of the study, a generalized solution of the problem of transverse oscillations is constructed. For the problem of damping oscillations, the exact damping time is obtained, namely, a time T0 at which the total energy of the system is zero. Optimum control is found in the form of a Fourier series. Keywords: damping oscillations, hyperbolic equation, Coriolis acceleration, trigonometric moment problem, Riesz base For citation: Muravey L. A., Petrov V. M., Romanenkov A. M. The Problem of Damping the Transverse Oscillations on a Longitudinally Moving String. Vestnik Mordovskogo universiteta = Mordovia University Bulletin. 2018; 28(4):472–485. DOI: https://doi.org/10.15507/0236-2910.028.201804.472-485 Acknowledgements: The work was supported by grant No. 16-01-00425 A from the Russian Foundation for Basic Research.

The Installation for Processing of Parts with a Complex Profile of Working Surface

Introduction. The article presents new solutions for designing the equipment for final processing parts with a complex profile of working surface. The said solutions allow a planetary rotation of the part at a small center distance of the mandrel with the workpiece and the spindle of the installation. This solution improves the quality of the working surfaces and reduces energy costs. Materials and Methods. The disadvantage of modern devices for final processing of complex parts is the increased energy consumption and the large axial distance between the part and spindle. These factors reduce the quality of processing and the part range in terms of weight and dimension characteristics. The application of new solutions to change the design of the installation is relevant. When designing a new installation, the center distance between the part and the spindle was reduced. This contributed to the reduction of vibrations, improving the quality of surface treatment and increasing the product range. Results. The calculations to reduce the resistance of the abrasive medium affecting on the surface of the diesel engine turbo-compressor wheel blades confirmed the expediency of the solution. The calculations of the part for deflection by using Solid Works 2016 software were carried out. The calculations demonstrated the reliability of the installation when processing parts of medium and large sizes as compared to the basic installation option previously made by Penza State University for Penzadieselmash Company. Conclusions. The calculations made it possible to find that the reduction of the center distance reduces the deflection of parts and vibration in the process of finishing and allows stabilizing the quality and performance of processing the surfaces of a complex profile with less energy coast. A new design of the installation was developed and manufactured. It contributes to planetary rotation of the part at a small axial distance of the mandrel with the part and the spindle of the device. Keywords: theoretical study, result of study, complex surface, part surface, loose abrasive particles, performance, quality indicator, equipment design, design calculation automation For citation: Skryabin V. А. The Installation for Processing of Parts with a Complex Profile of Working Surface. Vestnik Mordovskogo universiteta = Mordovia University Bulletin. 2018; 28(4):552–561. DOI: https://doi.org/10.15507/0236-2910.028.201804.552-561

The Resource of Movable Sealing Joints with the O-Ring Seal

Introduction. The problem of reliability of hydraulic drives sealing joints remains unsolved. However, the current level of computer modeling tools development allows us to solve effectively the problems of their longevity by replacing laborious experiments with high-performance computing. This paper presents the results of the approbation of the author's methodology for realizing computational approaches to determining the life of sealing joints on the basis of circular cross-section seal of hydraulic booster for MTZ (Minsk Tractor Works) tractors. Materials and Methods. The determination of mobile sealing joints resource is based on the author's methodology, which used ANSYS for realizing a series of accelerated loading cycles that simulates real operating conditions. The developed models consider the processes of wearing, relaxation and hydrodynamic effects acting in a sealing joint. Results. The use of the finite element modeling tools made it possible to determine the change in the stress-strain state of the power steering tightener in MTZ tractors during operation. The mechanism of joint tightness restoration on the basis of self-packing effect is revealed. The comparison of the forms of sections, obtained as a result of numerical and micrometer studies, confirms the effectiveness of the proposed methodology and the adequacy of the results obtained. The analysis of the obtained graphs shows that under normal operating conditions, the life of the sealing joint “cylinder ‒ piston” and “rod ‒ cover” is 2 and 1.12 years respectively, and as the temperature and pressure of the hydraulic fluid increase, decreases exponentially. Conclusions. The results of the study show the high efficiency of the author's methodology. This technique can be used in researches to determine the resource and criteria for the leak-tightness of sealing joints. The graphs of the dependence of the sealing joints life on temperature and hydraulic pressure allow companies, specializing in the creation and repair of hydraulic drives, to develop schedules of preventive measures for their maintenance considering a complex of operational factors. Keywords: seal, O-ring, hydraulic drive, reliability, life, service life, wear, relaxation, ANSYS, finite element analysis Acknowledgements: The study was supported by the Russian Foundation for Basic Research and the Government of the Republic of Mordovia in the framework of the project “Obtaining and research of new composite polymeric materials containing finely dispersed and nanosized modifiers for machine tribo-conjugation elements” (Grant No. 18- 48-130007а_р). For citation: Kuznetsov V. V. The Resource of Movable Sealing Joints with the O-Ring Seal. Vestnik Mordovskogo universiteta = Mordovia University Bulletin. 2018; 28(4):562–582. DOI: https://doi.org/10.15507/0236-2910.028.201804.562-582

Evaluation of the Influence of Motor Oil Ultrasonic Processing on the Wear of Friction Pairs during Long-Term Wearing Tests

Introduction. The influence of ultrasound parameters on the properties of processed lubricating oils and wear characteristics of friction pairs is a relevant problem in agricultural engineering. The paper presents a simple method for influencing on the lubricating oil by ultrasonic vibrations of the optimum frequency and power that results in reducing the wear of the interfaces of mechanisms and machines. The authors study the change in the physical characteristics of the oil during its ultrasound treatment and the assessment of their effect on the wear of a friction pair during long-term tests. Materials and Methods. We used a generator with variable signal parameters, a lever scale, a burette and an alcohol thermometer to assess the change in coefficient of surface tension of engine oil during sonication. Long-term tribotechnical tests were carried out on 2070 CMT-1M friction machine according to the “roller ‒ pad” scheme. The mass of these samples after long-term tests was weighed by Sartorius company analytical scales with a measurement accuracy of 0.00001 g. A profilograph-profilometer of Taylor Hobson Company was also used. Results. As a result of the research, the optimum frequency and power of ultrasound were revealed for lubricating oil processing. The decrease in the surface tension coefficient of oil was more than 5 %. With prolonged wear tests, the wear factor was reduced by 28 %. Conclusions. The effect of increasing the wear resistance of friction pairs when exposed to ultrasound oil is associated with a decrease in its surface tension coefficient, which allows the oil to be distributed with minimal effort over the surfaces with forming a film of sufficient thickness, which increases the bearing capacity of rubbing surfaces. Keywords: wear, surface tension coefficient, motor oil, tribotechnical test, ultrasound For citation: Simdiankin A. A., Davydkin A. M., Slyusarev M. N., Zemskov A. M. Evaluation of the Influence of Motor Oil Ultrasonic Processing on the Wear of Friction Pairs during Long-Term Wearing Tests. Vestnik Mordovskogo universiteta = Mordovia University Bulletin. 2018; 28(4):583–602. DOI: https://doi.org/10.15507/0236-2910.028.201804.583-602 Acknowledgments: The study was conducted with the financial support of the Ministry of Education and Science of the Russian Federation (state task, direction: development of competencies) project no. 11.3416.2017/4.6 “Development of technologies and tools to improve the durability of parts, assemblies, machines and equipment by creating nanostructured coatings sources of concentrated energy”.

Automated Unit for Magnetic-Pulse Processing of Plants in Horticulture

Introduction. The current level of agricultural production, including horticulture, is determined by intelligent machine technologies and new generation technical means with modern information and instrument support. The implementation of digital intelligent agricultural technologies in industrial gardening requires a fundamental change in the paradigm of technical support, based on the development and application of new automatic and unmanned machines, equipment and software for managing work processes of machines, navigating technical means, controlling the implementation of technological operations, monitoring the yield of agricultural crops, analyzing diseases and pests on plants and other technological functions. Materials and Methods. 3D model is visualized in the computer-aided design “KOMPAS-3D” through using the methods of mathematical modeling, theoretical mechanics and optimal design. A prototype of an automated unit for magnetic pulse processing of plants is made. The program code for calculating the required movement of the actuator rod is developed in the Sublime Text editor. C++programming language was used. The functionality of the computer program is related to the capabilities of controllers STM32, Arduino Mega/ Uno/Nano. Nextion 2.4 (the TFT screen 320x240) for the graphical output and interaction was used. Results. An automated unit with the algorithm of the drive control system of working bodies were developed during the technological operation of magnetic pulse processing of plants, taking into account the agro-technological parameters of garden plantations. A computer program with both automat and remote control was designed for driving the working bodies. Conclusions. The unit allows introducing a new environmentally safe technological method of stimulating vital and growth processes of fruit crops. This device provides the most efficient operation through automatic adjustment to various agro-technological parameters of plantings, providing the required value of magnetic induction in the working area on plant objects in the field. Keywords: magnetic pulse processing, control system, automated unit, irradiation of plants, gardening, low-frequency magnetic field For citation: Smirnov I. G., Khort D. O., Filippov R. A., Kutyrev A. I., Artiushin A. A. Automated Unit for Magnetic-Pulse Processing of Plants in Horticulture. Vestnik Mordovskogo universiteta = Mordovia University Bulletin. 2018; 28(4):624–642. DOI: https://doi.org/10.15507/0236-2910.028.201804.624-642

The Parametrization of the Cauchy Problem for Nonlinear Differential Equations with Contrast Structures

Introduction. The paper provides an analysis of numerical methods for solving the Cauchy problem for nonlinear ordinary differential equations with contrast structures (interior layers). Similar equations simulate various applied problems of hydro- and aeromechanics, chemical kinetics, the theory of catalytic reactions, etc. An analytical solution to these problems is rarely obtained, and numerical procedure is related with significant difficulties associated with ill-conditionality in the neighborhoods of the boundary and interior layers. The aim of the paper is the scope analysis of traditional numerical methods for solving this class problems and approbation of alternative solution methods. Materials and methods. The traditional explicit Euler and fourth-order Runge-Kutta methods, as well as the implicit Euler method with constant and variable step sizes are used for the numerical solution of the Cauchy problem. The method of solution continuation with respect to the best argument is suggested as an alternative to use. The solution continuation method consists in replacing the original argument of the problem with a new one, measured along the integral curve of the problem. The transformation to the best argument allows obtaining the best conditioned Cauchy problem. Results. The computational difficulties arising when solving the equations with contrast structures by traditional explicit and implicit methods are shown on the example of the test problem solution. These difficulties are expressed in a significant decrease of the step size in the neighborhood of the boundary and interior layers. It leads to the increase of the computational time, as well as to the complication of the solving process for super stiff problems. The authenticity of the obtained results is confirmed by the comparison with the analytical solution and the works of other authors. Conclusions. The results of the computational experiment demonstrate the applicability of the traditional methods for solving the Cauchy problem for equations with contrast structures only at low stiffness. In other cases these methods are ineffective. It is shown that the method of solution continuation with respect to the best argument allows eliminating most of the disadvantages inherent to the original problem. It is reflected in decreasing the computational time and in increasing the solution accuracy. Keywords: contrast structures, method of solution continuation, the best argument, illconditionality, the Cauchy problem, ordinary differential equation For citation: Kuznetsov E. B., Leonov S. S., Tsapko E. D. The Parametrization of the Cauchy Problem for Nonlinear Differential Equations with Contrast Structures. Vestnik Mordovskogo universiteta = Mordovia University Bulletin. 2018; 28(4):486–510. DOI: https://doi.org/10.15507/0236-2910.028.201804.486-510 Acknowledgements: This work was supported by the Russian Science Foundation, project no. 18-19-00474.

Technological Improvements of Grain Preparation for Milling in Small Enterprises

Introduction. In small enterprises with simplified technological process of graded milling, preparations, which involve cleaning, peeling and moistening grain, play an essential role for ensuaring high quality of graded flour. Modern equipment for the low-productive mills implies only dry cleaning of grains in an abrasive machine with their further cold conditioning. The equipment designed for graded milling with deep multiple cleaning, washing and hydrothermal treatment is not possible. It significantly increases the cost of flour. The aim of the study is to increase both qualitative and quantitative indicators of graded flour in small enterprises through peeling and drying of grains before milling. Materials and Methods. The quality analyses of grain processing according to such indicators as ash content (whiteness), moisture, quantity of fractured grains were carried out according to State Standards of the Russian Federation and the methods established in science and practice. The degree of peeling was determined by the whiteness indicator with a photoelectric whitener SKIB-M (GOST 26361-2013 “Flour. Test method for whiteness”). Grain moisture was determined according to GOST 13586.5-2015 by the drying cabinet DEC-3M (drying electrical cabinet, model type 3M). The number of fractured grains was determined according to GOST 30483-97. Results. The research result revealed the dependence of grain processing on the technical aids. А combined peeling–drying machine was developed on this principle. The authors have developed rational operations of grain processing, which increase the whiteness of the received flour on average 4–7 conventional units. The standard instrument for whiteness definition has been studied and set. According to the given results optimal operating parameters for grain processing before milling have been developed: machine productivity (Q = 700 kg/h); the period of grain processing (t = 72 s.); optimum moisture content (from the point of view of obtained flour whiteness) of grains received for milling (W = 14 %); radiant power (P = 1 000 W). Conclusions. The research proved the fact that peeling of grains is one of the most effective ways of increasing the grade of end products of small enterprises with simplified technological process of graded milling. The efficiency of peeling seeds of wheat with humidity higher than 16 % decreases that speaks for the need to dry grains. The authors of the article introduce the equipment and technology for grain processing before graded milling, which provide grain peeling and, if necessary, drying. The operating parameters of the peeling-drying machine for preparation of grains for milling have been determined. The developed technology provide, if necessary, drying the remoistened grain to necessary standards that gives the chance to produce high-quality flour from the grains processed hydrothermally without processing moisture conditions required. The machine productivity in the mode of drying should be connected with the power of microwave infrared radiation, and its time and power should be limited to a maximum permissible grain temperature, which does not exceed 60 ºС. Keywords: peeling, whiteness, moisture, drying, preparation of grain for grinding For citation: Anisimov A. V., Rudik F. Ya., Zagorodskih B. P. Technological Improvements of Grain Preparation for Milling in Small Enterprises. Vestnik Mordovskogo universiteta = Mordovia University Bulletin. 2018; 28(4):603–623. DOI: https://doi.org/10.15507/0236-2910.028.201804.603-623 Acknowledgments: The study was conducted as part of an agreement with the Foundation for Assistance to Development of Small Enterprises in Scientific and Technical Sphere (No. 180GS1 / 6784, 25 December 2014) under the “START-1” program together with “Healthy Food” LLC.

Developing the Automatic System for the Multi-Point Fumigation of Air Charge in the Diesel Engine

Introduction. The study deals with enhancement of an automotive diesel engine duty cycle through fumigating air charge by the certain dose (10−20 %) of hydrocarbon activator (alcohol, gasoline, kerosene, biodiesel, etc.). This is a relevant problem in engineering. In spite of its effectiveness, this method has not yet been widely applied to machinery. The existing mechanical devices for fumigating air charge do not provide the exact dosage of activator and its timely supply in a diesel engine at different operating modes. Materials and Methods. The solution for this problem may be the development of an automatic system for the multi-point fumigation of air charge. This device performs the injection of activator into the diesel engine intake manifold branches with the help of electromagnetic injectors managed by the electronic control unit. The system should provide the injectors operation by the algorithm for the cylinders firing order and calculate the injection duration for the adjusted activator dose. For the programming of the Electronic Control Unit, the injection duration of the exact activator dose was theoretically calculated. The algorithm of electromagnetic injectors operation was substantiated (for D-243 tractor diesel engine by the example). Results. To implement the multi-point fumigation of air charge, it was determined that depending on the activator dose and the engine speed and load mode, the cyclic dose of activator amounts may be from 1 mg per cycle to 13 mg per cycle, while the activator injection duration is from 0.27 ms to 3.5 ms. For the practical realization of the multi-point fumigation of air charge for D-243 diesel engine of MTZ-82.1 tractor the automatic system was designed. The system consists of an activator tank, filter, electric pump, rail, pressure regulator, electromagnetic injectors, electronic control unit, fuel consumption sensor, and sensor of phase and crankshaft speed. Conclusions. The device solves the problem of the automatic fumigation of air charge at the intake stroke and helps to improve power, fuel economy and environmental indicators of the automotive diesel engines. Keywords: diesel engine, fumigation of air charge, activator, system, electromagnetic injector, electronic control unit, sensor For citation: Ryblov M. V., Ukhanov D. A., Ukhanov A. P. Developing the Automatic System for the Multi-Point Fumigation of Air Charge in the Diesel Engine. Vestnik Mordovskogo universiteta = Mordovia University Bulletin. 2018; 28(4):523–536. DOI: https://doi.org/10.15507/0236-2910.028.201804.523-536 Acknowledgements: The authors thank the engineer of PNIEI company A. V. Grunyushkin for help in invention of Electronic Control Unit and in programming of microcontroller; the President of GAKS-Armservis Research and Manufacturing Association, D.Sc. (Engineering), professor S. V. Seynov for help in manufacturing of the modified intake manifold for diesel engine. Special thanks to anonymous reviewers for the objective analysis of the article.

Modeling of Stress-Strain State in Connection Resource Defines of Volumetric Hydraulic Drive

Introduction. The article explores the stress-strain state of a distribution pair of aggregates of a volumetric hydraulic drive and the search for ways to increase its durability. Materials and Methods. In the process of studying, the generally accepted principles of the theories of friction, reliability, elasticity, mechanisms and machines, and mathematical modeling were used. To simulate the stress-strain state, an engineering analysis system ANSYS was used. Distribution pairs of hydraulic pumps 313.3.112, GST-112 and Sauer Danfoss 90R075 were chosen as objects of study. Results. As a result of the study there were obtained values of the real contact stresses and long-term current stress on the distribution of pairs of units of volumetric hydraulic drive: the 313.3.112 hydraulic pump is 26,93 MPa; for GTS-112 water pump is of 22.21 MPa for the Sauer Danfoss 90R075 hydraulic pump is 27,12 MPa. It is revealed that the area located on the discharge side is a subject to the greatest loads. This is the cause of one-sided wear of spherical surfaces, which is quite common in units decommissioned. The values of contact stresses in the joints hardened by the method of electric spark machining are on average 1.4 and 9.4 % lower than in not unhardened. In the process of electric spark machining there is a redistribution of stresses on the surface that leads to a decrease of the operating load in the connections. Conclusions. The study allowed modelling the stress-strain state in new and hardened distribution pairs of volumetric hydraulic drive units under operating conditions and suggesting ways to increase its durability. It was established that to increase the wear resistance of a resolving compound and the durability of the volumetric hydraulic drive aggregates, it is necessary to ensure that in distribution pairs the maximum bearing capacity is greater than the maximum long-term operating load in these connections. To solve this problem, it is proposed to create coatings with high tribotechnical properties by the method of electricspark machining. Keywords: resource-limiting compound, volumetric hydraulic drive, modeling, finite element method, bearing capacity, operating load, wear resistance, electrospark machining For citation: Ionov P. A., Senin P. V., Stolyarov A. V. Modeling of Stress-Strain State in Connection Resource Defines of Volumetric Hydraulic Drive. Vestnik Mordovskogo universiteta = Mordovia University Bulletin. 2018; 28(4):537–551. DOI: https://doi.org/10.15507/0236-2910.028.201804.537-551 Acknowledgements: The study was conducted with the financial support of the Ministry of Education and Science of the Russian Federation (state task, direction: development of competencies) project № 11.3416.2017/4.6 “Development of technologies and tools to improve the durability of parts, assemblies, machines and equipment by creating nanostructured coatings sources of concentrated energy”.

Project and Operations Management of Machine-Building Production

Introduction. The aim of this work is to develop the main guidelines of project and operations management at machine-building enterprises. Materials and Methods. The authors reviewed the state of application of the project and operations management of machine-building production in the automated mode. The review showed the complexity of its application due to a large number of factors, which must be taken into account when implementing. An approach was developed that allows solving the task using the automation of analysis processes and decision-making in production management. Results. The article establishes the main guidelines of the project and operations management, aimed at increasing productivity and reducing production costs based on modeling the state of production environment. It also defines the requirements for the model. A prognostic time model for forecasting the state of the enterprise production system has been developed. Conclusions.The tasks have been solved in this article allow increasing the level of automation of the processes of project and operations management of the enterprise in the conditions of quick-change production. The implementation of the developed approach to project and operations management of the enterprise will allow streamlining the launch of products with a reduction in the amount of work in progress and increasing the productivity of output. Keywords: technological process, project and operations management, design, prognostic model, production, labor intensity, productivity For citation: Tsyrkov A. V., Kuznetsov P. M., Tsyrkov G. A., Yermokhin Ye. A., Moskvin V. K. Project and Operations Management of Machine-Building Production. Vestnik Mordovskogo universiteta = Mordovia University Bulletin. 2018; 28(4):511–522. DOI: https://doi.org/10.15507/0236-2910.028.201804.511-522