The investigation purpose: simplification and ensuring tooling high performance of two-pair gear trains in machines with change gears. Methods used: numerical experiments for the characteristics definition of change gear sets in gear trains, a comparative analysis of different sets characteristics, a result visualization in a table form. Relevance of the method offered is substantiated with considerable labor intensity in the definition of the gear combination in gear trains by existing methods based on tables use mainly through possible way selection. Novelty: there are offered special algorithms of setup calculations decreasing operation time for the choice of gear combinations of gear trains. Basic results: there are developed computer programs for the definition of gear train combinations required and an electronic directory for machine-tool two-pair gear train setups recommended for use by workers of technological departments and in design service in production activities of engineering and motor car repair companies, in research centers and colleges (in thesis investigations, in training processes of engineering experts).
The paper considers a technique that allows to increase the efficiency of solving various types of production tasks based on simulation modeling. The technique considers the process of engineering modeling of technological system components in accordance with conceptual hierarchical levels, which with the deeper level provide an approximation of the simulated object from the initial correspondence in the form of equipment contours to the maximum in the form of a 3D component model based on 3D scanning. This technique allows to choose the most adequate option of modeling the technological system components, corresponding to the complexity of the production task solved by simulation modeling. The application of the technique in the design and engineering services of a machine-building enterprise allows to arrange the modeling process, select all its stages, assign performers, check the execution of the modeling process, ensure that the models correspond to the production task being solved. The technique effectiveness is confirmed by the given examples of solving production tasks of diverse complexity – simulation modeling of gear milling of helical bevel gears and circular tooth pulling. The purpose of the paper is to reduce the complexity of building 3D models of technological systems by engineering services of machine-building enterprises for solving production problems of diverse complexity thanks to the hierarchical structuring of input design information for building 3D models of a technological system and solved production tasks. Research methods: functional differentiation of processes. Research results and novelty: reducing the duration of solving production tasks of diverse complexity by decreasing the time of 3D modeling of technological systems. Conclusions: rational arrangement of engineering modeling based on the hierarchical structuring of input design information for building 3D models of a technological system and solved production tasks allows to reduce the duration of engineering modeling up to two times.
To improve functional properties of pre-eutectic silumins there are used many different methods having a complex effect upon processes of structure formation and physical-mechanical properties of alloys. In this paper there is offered a method for alloy operation characteristics increase by the example of wear-resistance by the impact of nanosecond electro-magnetic pulses (NEMP) upon silumin melt AK7ch (AL9). Melt illumination was carried out with the generator (NEMP) (GNI-01-1-6) submersible rod radiator. The melt was overheated to 900ºC and processed with NEMP with the length up to 25 min after that it was cooled at a rate of 20ºC/min. Slow cooling contributed to the formation of a structure close to equilibrium. Cylindrical ingots with a diameter of 0.06 m (60mm) and a height of 0.06 m (60 mm) were obtained. Wear-resistance was defined on a cross cut of ingots according to GOST 23.208-79. As a standard of comparison were used non-irradiated samples of silumin. It is defined that melt NEMP processing changes considerably parameters of crystallization, structure formation and increases silumin properties. At abrasive wear, silumin wear-resistance changes from the duration of melt electro-pulse processing according to an extreme dependence with the evident maximum at melt irradiation in the course of 15 min. At that in the edge area of the ingot wear-resistance increases by 1.54 times, and in the central one – by 1.34 times. This effect is explained by the fact that during melt NEMP processing during 15 min the characteristics of alloy micro-structure change considerably: morphology and dimensions of structural constituents. At that there is formed a qualitatively new fine structure of a non-dendritic type which ensures maximum values of alloy wear-resistance. The data obtained allow developing technology of wear-resistant silumin fusion intended for operation under abrasive wear conditions.
The purpose of this article is to develop a model for managing duplicates at a motor transport if there is an insurance reserve. The task is to minimize the total costs (losses) at the motor transport enterprise. For an optimal model of duplicates management, regardless of the supplier and the time of delivery, the insurance stock in the warehouses of motor transport enterprises will satisfy the demand for spare parts necessary for rolling stock. Also, taking into account the determination of the optimal size of duplicates, the prediction of sudden failures, as well as statistics maintained in the Procurement service of motor transport enterprises, the volume and frequency of orders for duplicates become known. Determining the size of duplicates batch of various classification and quality allows the MTS (material and technical support) services of motor transport enterprises to ensure not only an uninterrupted transport process, but increase the coefficient of technical readiness and save on previously unclaimed stocks (surpluses) ensuring the effective distribution of financial resources. Further research in this area will be aimed at determining duplicates quality, supplied to the motor transport enterprise and developing methods for assessing the risk of the impact of defects in spare parts on failures and further consequences.
The purpose of the work is to assess the safety of passenger cars in case of an emergency rollover on the body of railroad tracks. The paper introduces a method for predicting injury of railway transport passengers as a result of swinging over the wagon on the body of railroad tracks. The method of research is mathematical modeling of scenarios of swinging over the wagon on a flat bottom or earth tramp of the railway track. A model of a passenger compartment has been developed, which is supplemented with models of a roomette, hand luggage and an anthropometric dummy. The originality of the work is the use of mannequin models for an accident with the rollover of a compartment car on the body of the railroad tracks and obtaining data on the interaction of fit models and a compartment car. The result of the study is the reported values of possible injury to passengers during an emergency rollover of a passenger car. Namely, the values of the head injury criterion, cervical vertebrae, breast and hips of the crash test dummy have been obtained. In comparison of the two considered scenarios of swinging over the wagon, the value of the head injury criterion for overturning the car on an inclined surface is 15% higher, the neck injury criterion is 30% higher, and the hip and chest injury criterion is 23% higher for mannequins on the upper shelves of the compartment due to their interaction with hand luggage. The obtained values do not exceed critical ones. The most dangerous positions of the mannequin model in the compartment of the car are revealed. Conclusions concerning the sufficient safety of the passenger car are formed and recommendations for the development of additional technical solutions to improve the safety of passenger cars are given.
The work purpose is to increase the productivity of bulk material separation by means of engineering process development based on fundamentally new engineering equipment in the form of spiral sieves, the novelty of which is confirmed by six patents for invention of the Russian Federation. In the work there was used a complex method of investigations. Analytical methods allowed offering dependences for the definition of bulk material longitudinal motion speed in spiral sieves. Experimental investigations were carried out in order to confirm analytical dependences. The analytical investigation of bulk material separation into fractions for the purpose of conditional model choice for its description is presented. A mathematical model choice is fulfilled. There is analyzed a model of continuous medium and that of a material particle. A mathematical model is developed to determine a speed of longitudinal motion of bulk material from charging to unloading. There is presented not only a circuit and an experimental plant created in metal version, but the results of experimental investigations of bulk medium motion parameters subject to spiral sieve design peculiarities are shown which presented a coincidence level high enough.
The purpose of the work presented in the paper consists in the choice of radio-transparent material that can withstand loads influencing a nose cone of an aircraft during a flight. In the paper there is solved a problem which consists in comparing the characteristics of different materials used in aircraft industry both common materials and composites and in the choice of the most efficient field of materials that meet the requirements of radio-transparency, strength and heat-resistance. The investigation work is carried out by means of the collection, processing and analysis of data obtained through an experimental way and containing information on strength characteristics, radio-transparency characteristics, on the range of operation temperatures, density and rigidity of each kind of material analyzed. On the basis of the investigation results a field of application of the materials under consideration is offered: in accordance with physical characteristics of composites analyzed the most efficient solution will be the application of glass-ceramic composites for manufacturing radio-transparent nose cones exposed to strong temperature changes during short periods of time caused by super-sonic speed achieved during flights and glass-ceramics, but glass-plastic having lower density and heat-resistance – for manufacturing nose cones of sub-sonic planes which are not subjected to such high thermal loads, at that it was defined that aircraft steels and composites based on metal matrix are not suitable for manufacturing nose cones in view of their high density and low radio-transparency.
In the paper there are considered problems connected with the radial stiffness anisotropy of body borings for lathe spindle bearings. Factors having an influence upon stability of its operation characteristics of a machine-tool during idling are considered. The analysis of force factors having an influence upon bearings of a spindle unit during lathe idling is carried out. The work purpose is to determine a quantitative and qualitative situation in the changes of boring forms for spindle bearings under the impact of loads mentioned. As an object of investigations there is chosen the lathe “Vector” manufactured at the Middle-Volga machine-tool plant. A finite element modeling is carried out for deformation investigations in the body boring of the spindle unit under the impact of forces caused by weight and imbalance of the rotating spindle. There is shown a geometrical model of a spindle carrier body, the peculiarities of a finite element model formation and a procedure for the fulfillment of a numerical experiment are described, and approaches of boundary conditions setting are also considered. As a result of a finite element there are obtained values of finite element unit displacements lying on the surface of the body boring of the spindle carrier under the impact of the mentioned power factors. The results found are presented for illustration in the form of solid and flat graphical dependences. The analysis of numerical experiment results has confirmed the presence of the stiffness anisotropy in spindle unit bearings. The phenomenon of stiffness anisotropy in bearings was already under consideration in investigations carried out earlier. But the results of the numerical experiments carried out by us have shown that along with other factors the imbalance forces together with design peculiarities of body parts have an influence upon the constancy of elastic characteristics of bearings. The matter obtained can be used during development of measures for design changes in a spindle unit body with the purpose of stiffness anisotropy decrease in the borings for bearing.
The purpose of the research in this paper is to develop a promising airfield driverless tow truck to increase the economic efficiency of aircraft towing facilities, including unmanned aircrafts as well as to ensure reliable operation in various climatic conditions. The research methods include the analysis of the experience of using such driverless airfield tow trucks abroad, the theory of calculating traction and speed indicators and experimental studies conducted during the creation and study of field tests of devices used to load the driving wheels of a tractor. To achieve the goal, the configuration of the structure being designed and its intended composition are determined analytically. The operation of the designed device in the traction mode is considered, and the characteristic of calculating its indicators when moving along the support surface is presented. The presented material briefly illustrates the process from creating a model of a driverless airfield tow truck to the created design of an existing sample, which will later be used to conduct its full-scale tests and a comprehensive assessment of its strength traction and speed characteristics.
The purpose of the paper. In order to solve the problems of increasing the efficiency of machining operations of small diameter holes by milling, the optimal range of cutting modes and helix pitch for the machining strategy with helical interpolation is established. The reduction of labor intensity and costs of hole machining when treating holes in alloyed corrosion-resistant steels is experimentally confirmed. Research methods. In this paper, the issues of machining blind holes by helical interpolation milling with end cylindrical carbide cutters of relatively small dimensions in parts made of 12X18N10T alloy are considered. The features of this machining are availability of significant axial and radial components of the cutting forces with relatively low tool strength. This leads to the fact that a key factor of the tool failure is its mechanical failure, the cause of which is an increase in cutting forces due to the edge of the cutter being chipped. Research results and novelty. It has been experimentally proved that the most rational machining parameters to ensure the specified accuracy and surface quality of the machined holes when using a strategy of helical interpolation milling will be the choice of the helix pitch p = 0.2 mm, the feed range F = 0.075-0.11 mm /tooth, which corresponds to the minute feeds of the milling center 450-675 mm/min. Conclusions. The optimal range of cutting modes is found in the feed range from 450 to 675 mm/min, with a helical interpolation pitch of 0.2 mm. The accuracy and roughness of the holes obtained by milling with end mills with a diameter of 3 mm for steel 12X18N10T is evaluated.
The application of hardened steel parts for the purpose of wear-resistance increase becomes increasing spread in different branches of mechanical engineering. In view of high hardness of the work surface of parts, finishing is carried out by flat grinding. During the hardened steel grinding there are formed burns, cracks, admixtures of abrasive particles in the work surface which are inadmissible defects in a surface layer of critical parts mounted in the fuel unit of an aviation engine. The analysis of literature and company experience has shown that after thermal treatment instead of finishing is necessary to use surface finishing by a face milling method, but there are no sufficient recommendations for tool choice and cutting modes to date. Jointly with the educational department there are carried out theoretical researches of cutters for the face milling of the “selector housing” mass-produced parts consisting of corrosion-resistant 95H18-Sh steel with the hardness of 59÷61 HRC. In the paper there is considered a chemical composition of 95H18-Sh steel, a method for manufacturing a cast, its physical, mechanical and chemical properties. Taking into account data obtained for the face-milling cutter installation on the frame there was chosen Sandvik Coromant material for the replaceable cutting insert the base of which consists of hard alloy 1010 with PVD coating. Later on there was carried out selection of basic geometrical parameters and characteristics of a cutting plate and also a micro-geometry of a major cutting edge and a tip. Mass-produced replaceable through-away plates with R245-12 T3 M-PM number of 1010 hard alloy and PVD coating were obtained from the catalog of Sandvik Coromant company. At the end of the work a conclusion was drawn that the application of face milling will allow ensuring the requirements to the design documentation of the product, decreasing thermal and power stress of the process, increasing productivity, surface quality and excluding the necessity in abrasion, and the investigation results are applicable to the fulfillment of the complete factor experiment and computation of a simulator with the definition of the impact of variable factors upon a response function.
Currently, heterogeneous materials based on titanium and aluminum alloys are widely used as promising armor materials. When a ballistic object is exposed to the armor material, brittle cracks that occur at the contact point spread in such a way that composite material is in state of decay both deep into and along the interlayer boundaries of the joint, while there is a violation of the composite structure and loss of the mechanical strength of the armor element. In this regard, the task of developing new reinforcement schemes for composite armor is urgent. One of the most promising technologies in the field of creating and developing new composite non-metallic armor materials is explosion bonding. The authors of the work proposed a new scheme for reinforcing a heterogeneous metal material by means of explosion bonding, which uses internal perforated reinforcing layers that serve as elements preventing the development of brittle fracture at the point of ballistic contact. To increase the efficiency of the destruction of a ballistic object in the composite structure, the authors proposed the formation of highly solid intermetallic compounds at the boundary between the metal of the base of a viscous metal matrix and the reinforcing element by subsequent heat treatment of the material. The conducted micro-X-ray spectral analysis of intermetallic compounds showed their correspondence to the chemical compound α-titanium (TiAl3). Comparison of the obtained level of physical and mechanical properties of the developed heterogeneous armored material with analogues suggests that the expected level of the composite protection class against small arms is in the range from Br4 to Br5 according to GOST R 50963-96 with an armor thickness of 40 to 60 mm, which makes it possible to reduce the weight of armored vehicles significantly and, as a result, increase its tactical and technical characteristics.
There are considered analysis results of stress-strain state in the load-bearing structure of three versions of refrigerator cars with different arrangement solutions of refrigerating-heating plants (RHP) and a thermos car at its cooling with liquid nitrogen. By means of the “APM WinMachine” application there are presented model parameters of a basic universal body. The analysis of calculation results has shown sufficient strength and potentialities for updating an available car metal structure for the application as a universal body of a refrigerator car. Work purpose: the estimation of a stress-strain state in the load-bearing structure of a basic body for insulated cars of different types of refrigerator- and thermos cars. Investigation methods: for the analysis of the stress-strain state in a load-bearing structure in three versions of the bodies of refrigerator- and thermos cars under loads with “Normal” modes there was used the “APM WinMachine” software complex realizing a finite element method. Results and novelty: for the first time there are offered arrangement solutions for the location of refrigeration-heating plants earlier not used for refrigeration rolling-stock (RRS). A stress-strain state of the body of the thermos car at the impact of overpressure upon it of gaseous nitrogen evaporated in cargo compartment is estimated. Conclusions: the analysis of calculation results for all three versions of the RHP arrangement and a solid body of a thermos car has shown sufficient strength and possibility regarding simple updating an available body metal structure which may be used as a universal car set.
The problems of traction properties increase in locomotives are considered. The necessity in devices for instantaneous control of a friction coefficient of wheels and rails based on the impact of electric current or a magnetic field upon a wheel/rail contact area. There are defined basic fields of researches essential for the actual realization of such devices. It is defined that devices based on electric current impact require the introduction of considerable changes in the units of a crew part for wheel pair insulation and searches of problem solution in the separation of traction current and control one and the prevention of control current impact upon alarm systems. It is offered to consider magnetic amplifiers of adhesion as a solution of a short-term outlook which can be introduced in an existing locomotive fleet and those using current impact as a solution of newly-developed promising machines. There is offered a design of an individual traction drive simplifying a problem in the arrangement of devices for instantaneous control of a friction coefficient.
The paper is dedicated to the increase of reliability, life, resource and decrease of costs for maintenance of micro-turbine installations at the expense of rotor bearing timely maintenance and decrease of total work time of the installation in the mode of catastrophic wear. In the paper there is described a method for the active monitoring of rotor bearing state of the micro-turbine installation allowing timely notification of the workers in charge about essential turbine generator maintenance. The solution offered is fundamentally new in this field of investigations as it was not used earlier for the control of rotor bearing state of turbine generators. In the paper there are enumerated all components essential for the operation of the system and a method for their connection. A process for adjustment and updating the solution offered is described. As a basic component of the system for data collection there is used Arduino Uno controller. As a main software component is chosen Zabbix 5.0 monitoring system. The objects under investigation are described, and there are presented conclusions on effectiveness and economic purposefulness of the solution offered.
The work is dedicated to the formation of TiAl titanium aluminide coatings with cobalt and nickel additives by means of the method of mechanical alloying with the further maturing at high temperature in vacuum. Coatings were applied with the use of the ball mill of the planetary type upon VT1-0 titanium alloy substrate which were placed in the mill cup filled with metal powders. There is studied growth kinetics, a coating thickness is measured. A specific rate of metal powder sedimentation upon a titanium substrate makes from 4.6 to 11 g/(min•m2). Deposited layers have a mean thickness 70-180 mkm. There are studied thoroughly compositions and microstructure of mechanical-alloyed coatings. For that there were used methods of X-ray diffractometry and raster electronic microscopy. It is defined that the inner structure of coatings is heterogeneous. After deposited layer thermal treatment a metal interpenetration takes place first aluminum into particles of titanium, cobalt or nickel. Coatings are composite material the basis of which makes aluminide of RiAl titanium, and as inclusions there are other inter-metallides, titanium, cobalt or nickel and also aluminum oxide. Mean values of micro-hardness of coatings obtained are 1.2 - 3.4 times higher than of titanium substrate. The highest values of micro-hardness (more than 6.5 GΠa) after thermal treatment in vacuum are observed in TiAl-5%Co and TiAl-10%Co coatings. Micro-hardness of VT1-0 titanium alloy after annealing, vice versa, decreases by 1.3 times.
In the paper there is under consideration an effort to achieve the roughness index of Ra <0.8 with the aid of soft abrasive tool use. As a result the purpose of this work became development of the technology for surface quality improvement of parts manufactured with the aid of additive technologies. The authors carried out a number of experiments with the samples manufactured with the aid of the method of FDM print. With the aid of 3D Ultra 3 printer of EnvisionTec company. The samples were made of ABS-plastic in the amount of 6 pieces. On each sample there were defects after printing which contributed to the deterioration of surface quality in products. By means of TR220 profilometer there was measured roughness before and after the experiment. There was carried out dry processing and with the use of SCL. As a result, dry processing resulted in worsening surface quality, heavy wear of an abrasive tool and grain contamination. Analyzing the data obtained from the profilometer in the experiment and SCL use a considerable improvement of the surface layer quality at minimum allowance is observed. Investigation methods: in the work basis there are experimental methods of investigation. The investigations are carried out with the use of a microscope and profilometer. Processing investigation results was carried out as a result of the comparison of the measuring data obtained. Work Novelty: there are defined conditions of soft abrasive tool operation and SCL impact upon Ra indices. The results obtained indicate a possibility of Ra improvement on a part surface which is achieved due to a combined shaping with the aid of additive technologies and further machining carried out on a single technological basis. The experience without SCL use has shown the overheating possibility the result of which is a meltback and plastic sticking both on the surface, and on abrasive grains of the cutter which is inadmissible and results in considerable worsening of Ra on the surface machined and cutter wear. In view of this the SCL use in finishing is promising, but to achieve better results SCL chemistry must be improved.
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.
The development of the international trade and the entrance of domestic car manufacturers into international markets required bench equipment development for tests in accordance with the requirements of the European standards. In this connection the purpose of this work is to develop an experimental and methodical basis for the estimation of the strength correspondence of export railway produce to the European standard basis. In the work there is shown a description of the bench developed for static tests of rolling stock for loads corresponding to the European standard basis. In the requirements mentioned there is used a more extended list of loads and combination of efforts and the necessity in the application of longitudinal loads to the elements of the end wall in three levels should be particularly emphasized. On the test bench there are carried out static tests of the car of model 61-4514 for Egyptian national railways and the body of the motor-rail car of model 2853 for the railway infrastructure of Serbia.
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.
