MECHANICAL ENGINEERING
The paper analyzes reasons for application of plasma torches of special design for deposition of heat-resistant layers of thermal barrier coatings that contribute to minimum oxygen content in the zone of spraying. It contains detailed description of design for a plasma torch with a nozzle that allows better protection of a plasma stream against atmospheric exposure.
Heated inert gas (Ar) is fed inside the nozzle along its walls through holes in its end part. Air around a plasma jet is displaced, additional compression of the plasma occurs and due to this oxygen content is decreased in a coating and efficiency of material deposition is increased. An additional use of a tungsten insert in an electronic node makes it possible to create a pair of tungsten – tungsten in an electrode assembly and the life of the electrode assembly will be increased due to high erosion resistance, electrical conductivity, thermal conductivity and sufficient strength in 2–2.5 times while increasing spray performance through toughening regimes. The paper presents testing results of the developed plasma torch and its prototype for duration of continuous operation and intensity at 500 A current, 70 V voltage, nitrogen flow rate of 45 l/min (standard mode for deposition of oxide ceramics). Coatings from nickel–chromium–aluminum–yttrium powder have been obtained while using plasma torches with the same parameters of deposition and a comparative analysis of the technological properties have been made in the paper. The developed plasma torch has more qualitative characteristics of subsurface plasma coatings: increase in adhesive strength – by 1.4 times, material utilization ratio – by 1.3 times, micro-hardness – by 1.3 times, porosity decrease – by 2.3 times.
The paper proposes to reach such external energy which is sufficient for shifting carbide atoms and binding through application of resonance effect on frequencies that corresponds to sound wave spectrum. The energy is used to increase resistance of hard alloys with simultaneous preservation of high characteristics in hardness and density and which are operating under heavy technological conditions with an impact load. Method of aerodynamic strengthening has been developed and patented in order to impart new properties to hard alloys. While carrying out the strengthening the effect is reached due to high-energy action of sound waves on structure of hard alloys at low temperature. Milling of carbide phases and their redistribution, reduction of dislocation in internal structure, improvement structure parameters for specified operational conditions occur in strengthened hard alloys. The obtained results prove a resonance factor of energy deposition while using method of aerodynamic strengthening. It has been experimentally determined that in order to use this strengthening method for hard alloys there are two most efficient processing modes and each of them has up to five clearly expressed resonance amplitude spikes at specific frequencies and the most efficient one is the first mode. Attenuation ratios have been determined while processing hard alloys for every strengthening mode. Results of the research prove the fact that the method of aerodynamic strengthening is an efficient mechanism that changes properties of hard alloys operating with impact loads: improvement of wear resistance in hard alloy plates is reached by 20–40 % upon the expiry of 30 minute operational period while making strengthening at resonance frequencies.
The paper is devoted to study of a possibility to manufacture fluoroplastic products while using method of cold deformation of pressed blanks and research of peculiar features in mechanical behavior of fluoroplastic which are revealed during deformation that affects quality and accuracy of the manufactured parts. Manufacturing technique of fluoroplastic sealing rings which are obtained while using method of coiling a band blank on a cylindrical mandrel with further endurance in a wound state and subsequent cutting of a spiral on rings has been considered in the paper. An important stage in the development of the technological process is a calculation and a design of a tool (mandrel caliber) that ensure obtaining of ring products with the required size and shape. Deformation behavior of fluoroplastic under conditions of force action is significantly different from the behavior of the known classical materials and it has a number of specific features and manifestations. Therefore the problem for creation of a calculation methodology for tool development looks as a complicated one and it requires a justified approach while selecting a mechanical model of polymer. Considering the fact that fluoroplastic has a structure with a high degree of crystallinity, a mechanism and sequence of deformations in it due to load are largely similar to the behavior of metals and other low-molecular materials. It allows to use methods and approaches adopted in the mechanics of solids for a calculation of fluoroplastic products however it is necessary to take into account the fact that deformation processes in polymers proceed in time and have a different nature of elastic and residual deformations. When bending the fluoroplastic band in case of winding it on the mandrel residual deformations which provide the required size and shape play the most significant role. However elastic deformations which cause springing and change of size in a finished product after removal of loading are also important. It has been proved that an elastic zone of finite width which has a certain influence on accuracy of manufactured products with due account of all accumulated elastic deformations will be present in the field of a neutral layer even at high degrees of deformation. In this case, fluoroplastic is a multi-modulus material having elasticity which at stretching is significantly higher than in compression, and therefore elastic recovery is more associated with the area of stretched fibers. The authors have developed a methodology for calculation of the tool for obtaining rings of the required size on the basis of the analysis pertaining to deformation behavior of the fluoroplastic while taking into account specificity of its mechanical properties. The proposed methodology with a sufficient degree of accuracy is consistent with the results of experimental studies.
The paper presents a designed device for checking acuteness of injection needle point and development of methodology for conducting corresponding tests. Basic information on disposable injection needles including their purpose, structural elements and requirements for the state of their points. The paper describes a standard method for checking acuteness of injection needle point which is based on measuring maximum force for piercing a high-pressure polyethylene film of a certain thickness by an injection needle during its translatory motion at a given speed. A description is given of the design and operating principle of the developed device that implements this method for checking acuteness of injection needle points. Main provisions of the developed methodology for conducting these tests including sequence and content of actions during their execution have been set out in the paper. Results of the experiments on verification of acuteness in injection needle points of four-diameter confirm practical use validity of the developed device and methodology for conducting corresponding injection needle tests. The obtained oscillograms on changes in the force acting on a needle in the process of polyethylene film piercing are highly informative and that makes it possible to investigate in detail specific features at all stages of the process being studied, including both the stage of film piercing by a test needle and the subsequent stage of removing it from the contact with the film.
The proposed design solution refers to elements of land vehicle bodies and namely to control panels of a power truck and it can be used to control vehicles of technological purpose with electric traction, as well as their hinged and trailed equipment. A technical problem of a device coinciding with the positive result from its application is to provide a possibility for controlling hinged or trailed equipment of a transport vehicle of technological purpose with the help of a panel. The control panel has a steering wheel located on its left side mounted on a steering column, a speedometer and a section of vehicle control devices, and there is a control unit for hinged and trailed equipment of the vehicle in the right part of the panel; it is made in the form of a box and there is a group of indicating devices, keypad and two function keys on the outer box surface. The group of indicating instruments includes a line of seven-segment indicators, a text LCD-indicator, a graphic TFT-display, the first and second LEDs indicating the status of hinged and trailed equipment. Indicating devices, keypad and two function keys are electrically connected to the control unit located inside the box. The control unit is based on an industrial microcontroller equipped with a non-volatile memory unit and a USART module connected via an interface converter unit to a radio module.
The paper considers issues pertaining to creation of a model for controlling road traffic with the purpose to minimize delays on street and road network, which is proposed as an innovative one while developing an intelligent transport system of the large city that is Minsk. The developed model has a complex structure of algorithmic support. The first-level model has been implemented on the basis of fuzzy logic, for which a program has been developed and conditions have been determined, and operation of traffic light at a real local intersection of Minsk, which is included in the automated traffic management system, has been simulated. Innovation in the first-level model is an approach in determining conditions while detecting a fuzzy set without using a standard algorithm that is an algorithm of local flexible regulation. The paper proposes and investigates a model that works on the basis of operationally obtained parameters of traffic flow intensity at characteristic points (sections) of street and road network. Efficiency of the first-level model has been equal to 8 % due to optimization of a traffic light cycle (reduction of transport delays during passage of stop lines). Results of the simulation using the proposed computer program have made it possible to improve efficiency of traffic management on the studied highway (Logoysky trakt) in Minsk city of Minsk by 15 % due to decrease of delay level in case of unilateral coordination. The algorithm has been already implemented as part of the current automated traffic management system in the city of Minsk and it has shown its efficiency. However this efficiency can be increased if it is used together with an algorithm for searching maximum volume of motion in a cycle with a distributed intensity pulse. It has been planned to take into account this specific feature when increasing possibilities for algorithmization of traffic management.
In order to increase reliability and accuracy of robot manipulators or other construction equipment used for lifting operations an optimum dynamic mode for moving its boom system has been calculated in the paper. Results of the research have made it possible to construct a mathematical model for manipulator movement and obtain kinematic characteristics of the optimum dynamic mode. While determining the optimum dynamic motion mode, a criterion action has been used as an optimization criterion which represents a time integral with an integrand function expressing a dynamic component of manipulator drive power. Functions for changing kinematic characteristics of an manipulator boom have been calculated when it moves from one predetermined position to another one and which correspond to optimum dynamic mode of motion. Search for an optimum motion mode has been performed by minimizing the optimization criterion using the Euler–Poisson equations. In this case a generalized angle of rotation has been used which permits to relate movement of the boom and oscillations of its support part. As a linking component differential equations of system motion have been also applied, in which relationships between an oscillation angle, rigidity of a manipulator support, and its mass-geometric characteristics have been recorded. Results of the work can be useful for refinement and improvement of existing engineering methods for calculating the drive mechanisms of manipulators both at design/construction stages and in real operation modes, and the results can also be used while making design or improvement of similar executive mechanisms for construction equipment and robots.
Active use of parts synthesized while using additive technologies from powders is limited due to presence of residual porosity contributing to a decrease in strength, ductility, fracture toughness, crack resistance, workability by cutting, as well as tribotechnical characteristics. It has been proposed in order to expand scope of parts application derived from non-compact alloys to use methods of surface layer hardening. Specific features of local surface-plastic deformation have been investigated by diamond smoothing of samples from a sintered titanium alloy ВT1-0, as well as an alloy based on titanium aluminides LMD ОX 45-3 (Ti–45Al–3Nb) synthesized by selective laser sintering. It has been established that diamond burnishing is an effective method of compacting surface layer of samples from low-plastic non-compact materials obtained by various methods. It has been shown that in order to eliminate effectively porosity and increase strength of a surface layer for bearing surfaces of parts made from these materials, processing must be performed in a narrow range of mode parameters taking into account mechanical properties of the material, residual porosity and tool parameters. For example, application of diamond smoothers with a sphere radius of 0.5 mm leads due to a small contact surface of a tool and low ductility of the material being processed to destruction of the surface layer, as the tool “fails” into large pores, which causes spalling of the material or uneven effect of the tool on the surface layer. It has been determined that for the effective application of the established regimes it is necessary to take into account an initial porosity which has a random distribution over the surface area of the studied samples. For maximum compaction efficiency of an alloy based on a sintered titanium alloy ВT1-0, as well as an alloy based on titanium aluminides LMD ОХ 45-3 (Ti–45Al–3Nb), a cumulative effect of smoothing parameters should be taken into account.
ECONOMY IN INDUSTRY
Methodological basis for formation of system to ensure social and economic security make provisions for specific features of industrial sector. It is proposed to reflect specificity of its protection with the help of methodological and operational fundamentals. Methodological fundamentals have been formulated on the basis of functional specificity for ensuring social and economic security of the industrial sector which was determined with the help of research process. They create a perimeter for ensuring social and economic security which is formed by expectations of the society from defense system of the country’s industrial sector. Operational fundamentals complement functional specificity of the system for ensuring social and economic security through formation of a specific institutional framework. The framework includes the following components: modeling presupposing multivariance in escalation of adverse events in the industrial sector and methods for its evaluation; instrumental assistance which takes into account necessity for instrumental diversity in order to implement defense functions in changing criteria (environment of industrial sector functioning, its structure and state of inter-element relations); functional consistency as a requirement to balance targets for ensuring social and economic security of the industrial sector with objectives and values pertaining to formation of the country’s industrial sector which are fixed in program documents of the state.
Main development trends and complex of internal and external factors influencing on export potential of the industrial sector in the Republic of Belarus have been revealed and determined on the basis of the analysis of national and international statistical databases and method for expert assessment. Relevance of the research is to demonstrate that industry creates a significant part of commodity exports in the small open economy of the Republic of Belarus which has adopted a course to post-industrialization as a national strategy. Absolute figures of the Belarusian export of services are 3.4 times lower than values of the commodity export, 92.4 % of which is provided by manufacturing industry. It is in the sphere of industrial production that we should look for the reasons of long-term trend to reducing physical and cost volumes of Belarusian export, deterioration of its commodity and geographical structure, negative balance of trade and account of current operations. Main positions of the Belarusian commodity exports which form 70 % of its volume to non-CIS countries are raw materials exposed to unstable price environment in the world market, although the mining industry accounts for only 1.2 % while the manufacturing industry creates 85.6 % of the sector’s gross output. The study refutes the conclusion that problems associated with implementation of an export potential of domestic industry should be explained by the crisis of industrial production, proving that post-industrialization, accompanied by a reduction, curtailment or cross-border transfer of industrial production, is not so clear and does not bring the expected macroeconomic results. Reindustrialization, achievement of a breakthrough in the use of information technologies for a new quality of industrial production, which involves reorientation of IT-sector in Belarus operating on the basis of an outsourcing model from external to domestic market and solution of problems concerning system modernization of industry must become a national strategy aimed at the development and implementation of the industry’s export potential.
The paper analyzes approaches to interpretation of a competitive advantage source in various schools of strategic management. Systematizing concepts and approaches of foreign and national researchers within the framework of this or that strategy school the author of the paper gives preference to the Lakatos concept that various scientific-research programs may coexist and compete simultaneously. Strategic management science does not have any obstacle to compare competing theories in justifying sources of strategic competitive advantage. An internal logic of a theory serves as the basis to compare quality of verbal or formal school models, and consideration of successful / unsuccessful strategies in modern dynamically developing economy makes it possible to obtain data for empirical verification of the models. Purpose of the paper is to evaluate prospects of scientific-research programs proposed by various strategy schools in the context of their approaches to sources of competitive advantage. Evolution of science and practice in strategiс has led to shift in emphasis for understanding a company not as a set of business units but as a set of resources and competencies that contributed to obtaining a dominant position in strategic management of resource-based strategy concept. Search for sources of competitive advantage has been shifted to specific resources which a company possess. Such approach lays a solid foundation for a qualitative analysis of strong and weak points of the organization while forming a sustainable long-term advantage based on the development and protection of company's internal resources. Research of competitive advantage resources from the perspective of the concept of company’s dynamic abilities (modern stage of resource-based concept development) is considered as the most promising one because it is based on endogenous nature of advantage sources. This approach rejects implausible assumptions and emphasizes importance of an entrepreneurial factor.
ISSN 2414-0392 (Online)