METHODS TO ESTIMATE ECONOMIC EFFICIENCY OF APPLYING POLYMER-BITUMEN BINDERS

The implementation of the national project "Safe and High-quality Highways" is aimed at spreading the successful experience of using innovative materials, structures and technological solutions for federal projects at road facilities of regional and inter-municipal subordination. There are no approaches to evaluate the economic efficiency of using new and best technologies for the objects of regional subordination or they are not provided with a methodological basis for evaluating their total economic profitability. The objective of the research conducted by the group of authors is to develop methods to prove the efficiency of a wide range of innovations for objects of regional subordination. The research problem is to study the issues of effective transfer to the subjects of the Russian Federation of technological solutions used in construction and repair work on federal highways. This is due not only to the lack of experience in the application of innovations, the high cost of new production and laboratory equipment for their implementation, the small scale of the work carried out, but also significantly different operating conditions, maintenance of these road facilities. In this part of a comprehensive study conducted within the framework of the federal project "System-wide Measures for the Development of Road Facilities", the authors propose a methodological approach to calculating the efficiency of using polymer-bitumen binders. Cost-effectiveness analysis for arrangement of polymer-asphalt-concrete coatings on highways was used as the methodological basis for evaluating the economic efficiency of applying this technological solution.

SEARCH FOR WAYS TO IMPROVE THE TRACTION PROPERTIES OF LOCOMOTIVES AND TRACTION DRIVE DESIGN

The work objective is to increase the traction properties of locomotives without the use of traction drives with asynchronous traction motors and pulse width modulation. Research methods: methods of physical and field experiments, analytical methods for calculating the dynamics of the rolling stock. Conclusion: based on the conducted research, it is proposed to perform a promising diesel locomotive in the form of two sections on three two-axle bogies and a booster on two two-axle bogies, as well as to carry out experimental design work to develop an arc-type stator asynchronous motor and traction drives of a diesel locomotive using it.

SIMULATION OF DOOR MOVEMENT WITH A CLOSING MECHANISM

The work objective is to determine the parameters of the closing mechanism that provide the specified characteristics of the door movement. Research method: computer simulation of the movement of a door with a lock mechanism as a multi-mass dynamic system, taking into account the mechanical characteristics and contact interaction of the lock mechanism. Research results and novelty. Computer dynamic models of a door with a door closer and a door with a spring have been developed. The moments of the door opening force, the closing time of the door, the angular velocity of the door at the time of impact with the frame are considered as the criteria for the quality of the door closing mechanism. Formulas are obtained that determine the permissible values of stiffness and deformation of the door closer spring according to the specified moments of the door opening force. The movement of doors with a door closer and with a spring is compared. The parameters of the closing mechanism providing the specified characteristics of the door movement of the considered example are determined. It is shown that with the same values of the opening force moments, the speed of impact with the frame in the case of the door closer is less than the door with a spring. Conclusions: The developed computer dynamic models of a door with a door closer and a door with a spring make it possible to determine the characteristics of the door movement taking into account the inertial and mechanical characteristics of the door closer and spring mechanisms. The permissible values of stiffness and deformation of the door closer spring can be determined by the specified moments of the door opening force in two positions. It is established that the forces of air resistance and friction in the hinges of the door cannot create the moment of resistance necessary for smooth closing of the door without a strong impact on the frame with a limited closing time. The quality criteria that minimize the closing time and the speed of impact of the door with the frame are contradictory. The choice of optimal parameters of the door closing mechanism is possible if one of the criteria is replaced by a restriction. The developed formulas and computer models are recommended for use in the design of devices that restrict the movement of doors.

EXCAVATOR WORKING EQUIPMENT FOR ISLANDS OF PIPELINE REPAIR

Work objective. Modernization of the excavator's working equipment design intended for islands of pipeline repair together with confirmation of its operability by checking the machine for stability, carrying out the necessary calculations of the hydraulic system. Methods. The main idea is in accessorizing the main working equipment of the excavator with a structure consisting of three teeth, which is in a body with an excavator bucket form a pickup mechanism. To confirm the operability of the proposed design, theoretical studies have been carried out aimed at determining the stability of the machine for the most dangerous design operating positions, and permissible pipe sizes have been established so that working with these sizes provides the stability of the machine. Results. A variant of improving the design of the excavator working equipment of the third size group has been developed. The equipment is intended for carrying out random repair of the pipeline by the excavator without involving other road construction equipment (for example, a pipelaying crane). The proposed design of the working body allows speeding pipeline repair by reducing the time spent on changing or relocating the equipment, which as a result reduces the cost of repair work. Conclusions. Calculations of the excavator hydraulic system have been carried out. In addition, as a result of theoretical studies, calculated dependences have been obtained, which made it possible to establish the stability coefficient of the excavator of the third size group when working with upgraded equipment and the pipeline diameter in the range of 720 ...1420 mm. As a result of the research, it was found that the proposed equipment is effective for carrying out random repairs of pipelines with diameters of 720, 1020 and 1220 mm. The stability of the machine in the most dangerous positions is being carried out. The calculation shows that when the excavator does demolition works of a pipeline with a diameter of 1420 mm, there is a danger of overturning the machine due to a decrease in the Ku coefficient below the permissible value.

EVALUATION OF SURFACE DEFECTS OF PRODUCTS USING DIGITAL TECHNOLOGIES

The suggested approach provides an opportunity under the conditions of enterprises to give a comprehensive view of products defects and functional coatings imperfections. The application of the computer program developed in the Microsoft Visual Studio environment, which allows digital image processing of the studied surfaces to estimate the area of external defects of materials, regardless of the nature of the origin of defects and the method of image acquisition, is proved. Research methods. Digital images of metal surfaces and coatings obtained by energy dispersive microanalysis, electron and optical microscopy have been tested. Research results and novelty. The possibility of using the program for evaluation of surface bands with local chemical and morphological inhomogeneities, determination of the porosity of materials is shown. The possibility of express evaluation of digital images of objects at macro-, meso- and microstructural levels for automated diagnostic control of surface defects within 1-2 seconds is implemented. Disaggregation of brightness, texture and color components of the image significantly increases the speed and efficiency of image processing structures. Conclusions: The proposed program is versatile, does not require special user skills and serves as a convenient tool for analyzing and controlling the quality of objects of various physico-chemical nature. The results of the study indicate that the application of the developed computer program makes effective quantitative calculation of the area of local defects, areas of distribution of chemical elements, various inclusions, surface porosity of products and coatings possible.

ENSURING TIGHTNESS IN PRESSURE COUPLING PARTS

Work objective is to solve the urgent problem of increasing the tightness and reliability of pressure couplings during their operation under dynamic loads. Theoretical and experimental studies assessing the impact on the tightness due to roughness nature of mating surfaces and three types of coatings: soft, double-layer and hard have been undertaken. The joints were tested under the influence of axial cyclic load and torque on a bench for accelerated testing. It is established that tightness of pressure couplings during operation under dynamic loads significantly depends on the parameters of microgeometry and physical and mechanical properties of the mating surface material that determine their actual contact area. Recommendations for preparing the surfaces of parts before pressure coupling assembling have been developed. It is proved that the use of regular microrelief and soft galvanic coatings of mating surfaces have a significant effect on the tightness of pressure couplings.

SOLVING THE MULTI-CRITERIA TASK OF DETERMINING THE CRITERIA FOR THE EFFECTIVENESS OF THE TRANSPORT AND LOGISTICS SYSTEM

Work objective. The article considers the process of optimizing transport and logistics system in various areas of work and represents the task of solving a complex multi-criteria system. Determining the most optimal and accurate way to solve this problem will lead to a significant stimulation of the management processes of transport and logistics complexes, in particular trucking. Research methods. The research was carried out by analyzing the solution of multi-criteria mathematical problems. Novelty of the work. The novelty of the work is due to the need to solve the main problems of optimizing the operation of the transport and logistics system. The solution of this task will stimulate the country's economy by increasing the volume of annual shipping goods, as this indicator is one of the key road transport complex of our country. Research results and novelty. According to the results of the study, the main ways of solving the problem of optimizing the transport and logistics system are determined. Conclusions: The main criteria for solving a multi-criteria task in optimizing the planning, organization and management of terminal and warehouse complexes of work are determined.

THEORETICAL MATHEMATICAL MODELING OF HEAT EXCHANGE IN PIPES WITH TRIANGULAR AND SQUARE TURBULATORS WITH d/D=0.95÷0.90, t/D=0.25÷1.00 AND HIGH REYNOLDS NUMBERS Re=106

Mathematical modeling of heat exchange process in straight and round horizontal pipes with protrusions and d/D=0.95...0.90, t/D=0.25...1.00 of triangular and square sections with large Reynolds numbers (RE=106) are carried out on the basis of multiblock computing technologies based on solutions of factored and finite-volume algorithm of RANS equations and energy equations. It is shown that for higher square protrusions and at higher Reynolds numbers, a limited increase in NU/NUgl is accompanied by a significant increase in relative hydro resist ance in accordance with the higher Reynolds number; for triangular turbulators, this persists and even deepens.

UNMANNED URBAN AIR MOBILITY: TECHNOLOGIES OF THE NEAR FUTURE

The further development of urban mobility, taking into account the latest technical and technological achievements, is considered by many leading vehicle manufacturers in creating and introducing unmanned urban air mobile vehicles into the urban environment. Despite the fact that currently the development of these means of transportation of passengers and cargo is actually in the technical plane - the integral success of introducing this type of transport depends on multiple socio-technological aspects of this phenomenon, which will have various social consequences. The objective of this paper is to identify the socio-technological issues of the phenomenon of unmanned urban air mobility. The result of this paper is to make recommendations to developers of unmanned urban air mobile vehicles in order to minimize the damage from ignoring the negative socio-technological consequences of introducing this type of transport into the urban environment. The novelty of the paper lies in the fact that this type of transport was studied not from a technical and technological point of view, which is the leading one at this stage, but using a socio-technological approach. The paper clearly proves that unmanned urban air mobile vehicles are also multifaceted social objects.

METHODOLOGICAL FOUNDATIONS OF DIAGNOSTICS OF METALWORKING TECHNOLOGICAL SYSTEMS ACCORDING TO PARAMETRIC RELIABILITY OF ENSURING A GIVEN QUALITY OF THE TREATED SURFACES

The paper presents the results of research justifying the need for diagnostics of metalworking technological systems on the reliability of ensuring the quality parameters of the surfaces of machine parts during machining. The fundamentals of the methodology of its implementation have been developed. Theoretical models of forming the quality parameters of parts surfaces during machining are considered and refined. This characterizes the scientific novelty of the results obtained. Circuitries for the construction of experimental control systems when conducting bench tests of machined surfaces of parts in conditions close to operational are of practical value. Circuitries are developed and computerized systems based on them for measuring the quality parameters of machined parts surfaces, including the working area of the technological system, are implemented. Recommendations on the rational choice of technological systems and the use of simulation methods in the study of parametric reliability of technological systems are presented. Mathematical and software analysis and processing of experimental results are developed and tested. These results will serve as a foundation for further development of research in the field of parametric reliability of technological systems, improving the quality of domestic engineering products and increasing their competitiveness at the world market.