Другие журналы

scientific edition of Bauman MSTUSCIENCE & EDUCATIONBauman Moscow State Technical University. El № FS 77  48211. ISSN 19940408
# 08, August 2013
Machine Building and Engineering Science
Thread cutting using thread taps and with preliminary plastic deformation of the material of the layer to be cut
# 08, August 2013 DOI: 10.7463/0813.0570897 Results of technological tests of thread cutting using thread taps and with preliminary plastic deformation of the material of the layer to be cut are presented in this article. It was experimentally established that task oriented change of physical and mechanical properties of the surface which is processed during thread cutting may lead to decrease in tension of the cutting process along with the increase in tool durability and geometrical accuracy of the thread profile. For example, thread cutting in details made of 20H13, 12H18N9T and 50RASSH steels with additional mechanical hardening provides decrease in rotational moment by 1626% in comparison with the traditional method of thread cutting by means of thread taps; tool durability was also increased by the factor of 1,31,8 and in isolated cases it was possible to reduce the number of thread taps in the set and increase process efficiency.
Stressstrain state in a combined operation of expansion and swaging when manufacturing adapters
# 08, August 2013 DOI: 10.7463/0813.0578962 The authors consider a combination of two operations (expansion and swaging) in one manufacturing step. A coordinated solution to equilibrium equations, plastic conditions, relations between stresses and strains were used during the analysis of these operations. As a result, data were obtained for calculation of effective stresses and strains for both zones  swaging and expansion. The results of the study and calculation of the friction effect on the magnitude of stress and strain state in the combined operation are given in this work. Methods of controlling the formation process were defined. A numerical experiment was carried out with the use of MATCAD by varying the main parameters of the process which are friction and strain.
Constructional Material Processing in Machine Building
A study of lathing characteristics on the basis of obtaining and analyzing multidimensional polynomial dependences
# 08, August 2013 DOI: 10.7463/0813.0589299 This article considers a possibility and an algorithm of the mathematical study of polynomial dependences which are used for describing characteristics of machining. The authors describe advantages of polynomial dependences obtained on the basis of a complete factorial experiment in multidimensional parameters spaces. For illustrative purposes, an analysis of energy consumption during twostage lathing was carried out on the basis of the obtained polynomial dependence of the tangential cutting force on processing factors. The influence of the specified factors was established a priori on the basis of conducted experimental studies or literary sources. Conditions and results of all the conducted experiments are presented in this paper along with the algorithm for determining the minimal value of energy consumption.
Practicability of purchasing new metalcutting machinery
# 08, August 2013 DOI: 10.7463/0813.0587093 An approach to decision making on practicability of purchasing new metalcutting machinery in the context of processing’s prime cost was proposed; this is an actual problem for many machine builders which upgrade their machine tool population. It was shown that the cutting speed that provides minimal prime cost is a key to this problem. A formula for estimating the lowest prime cost of cutting action was derived. The author analyzed key factors influencing the solution to the problem of practicability of purchasing a new metalcutting tool. It was also shown that it is impossible to reduce the prime cost of processing by increasing cutting speed. The only way to reduce the prime cost of processing by new equipment is a decrease in auxiliary time. The area of unprofitability of old machinery replacement was determined.
Investigating the influence of cutting conditions on wear of thread cutters with an internal chipcarrying
# 08, August 2013 DOI: 10.7463/0813.0583417 This article provides results of investigations aimed at reasoning of the increase in the working capacity of a new type of thread cutters with an internal chipcarrying. Determination of the wear criterion, which characterizes the admissible wear limit, is an important stage for estimating the working capacity of the thread cutter. This criterion, in general, depends on the kind of failure, cutting conditions, tool and work materials, structural and geometric parameters.
Influence of pressure on supporting surfaces of the cutting profile on the accuracy of the thread being cut
# 08, August 2013 DOI: 10.7463/0813.0590745 The author developed a mathematical model that sets basic laws of changes in specific forces in formation of the thread surface and allows one to determine priorities of technical activities aimed at improvement of accuracy and stability of the process of threading. Pressure diagrams for tap tool minor cutting edges were obtained. This is useful for load distribution analysis between cutting teeth. Results of theoretical and experimental studies on the effect of the cutting angle of the taps on the dynamics and precision of the threading process are presented in this paper. A correlation between the character of overpressure on instrument base surfaces and a classification of thread types was determined.
Power Machine Building, Metallurgical Machine Building and Chemical Engineering
Mathematical model of vacuum nitrocarburizing of the complexalloyed VKS10 steel
# 08, August 2013 DOI: 10.7463/0813.0569132 This paper presents a mathematical model of a cosaturating complex alloy steel with carbon and nitrogen in the low pressure atmosphere. They developed software that gave an opportunity to estimate concentration curves of carbon, nitrogen, and basic alloying elements for VKS10 steel, as well as the main characteristics of the phase composition in tabular and graphical forms on the basis of the parameters of vacuum nitrocarburizing. The effect of the complex chemical composition of the steel on formation of the diffusion layer was taken into account. Sufficient adequacy of the model within the temperature range from 880 to 940 ° C was demonstrated; these temperatures are the same as during hightemperature nitrocarburizing. With the help of this mathematical model patterns of formation of diffusion layers depending on technological factors of vacuum nitrocarburizing were investigated.
Transportation, Mining and Construction Machine Building
Analysis of influence of structural factors on passive safety of a truck cab at a frontal impact
# 08, August 2013 DOI: 10.7463/0813.0580257 The purpose of this article is to analyze the influence of structural factors of truck cabs on parameters affecting passive safety (doors, lining boards, use of aluminum foam, etc.). According to the calculation results, the maximum movement of the primary elements of the design was estimated along with the residual living space; the authors also analyzed behavior of door frames, window frames, pillars, side members, the remaining elements of the cabin. The design experiences contact, buckling, wrinkling, bending, appearance of plastic hinges. In order to improve the design, the most flexible areas and areas with plastic hinges were determined. For indirect assessment of the cabin stiffness it was proposed to use, beside the recommended volume of the living space in a cab, acceleration of the mannequin’s center of mass the maximum value of which in a certain moment of time is also specified. Design modifications for the truck cab were developed on the basis of a comprehensive analysis of the influence of structural factors on passive safety on the frontal impact; these modifications improved safety of the truck.
Development of an adaptive relay control law for damped suspension of multiwheeled vehicles in order to prevent linearangular fluctuations in the housing
# 08, August 2013 DOI: 10.7463/0813.0567732 The required level of damping a multipleseated oscillatory system, as it is known, depends on the nature of the external impact. In this case, regulation of damping characteristics depending on the operation mode of depreciation systems is one of the main directions of further improvements. Increasing the quality of primary control systems for suspension of multiwheeled vehicles with the number of axes more than three appears to be very promising. An adaptive relay control law for damped suspension of multiwheeled vehicles was developed in order to prevent linearangular fluctuations in the housing. Methods of simulation modeling were used to determine that efficiency (reduction of variance of vertical accelerations at the driver's place compared to the unmanageable suspension) of the adaptive law of counteraction to linearangular fluctuations is 7...22%. Introduction of an adaptive component increases efficiency of the algorithm by 5...10% compared to the nonadaptive law.
Mathematics and Mathematical Modeling
Localization of invariant compact sets of the discretetime Lozi system
# 08, August 2013 DOI: 10.7463/0813.0609276 One of the methods of qualitative analysis of a dynamical system is to estimate the position of its compact invariant sets closely associated with bounded trajectories of the system. As a solution to such a problem, one can use a localizing set, i.e. a set in the phase space which contains all invariant compact sets of a system. In this paper the discretetime dynamical Lozi system of second order was considered. This system was proposed as a piecewise linear analogue of the known discretetime Chenon system which has a chaotic attractor for some parameter values. For positive invariant and negative invariant sets of the Lozi system a family of localizing sets was constructed and their intersections were determined. The results of this investigation were presented in figures.
Numerical solution of coalitionfree matrix games
# 08, August 2013 DOI: 10.7463/0813.0587745 A general case of weakly investigated Nperson matrix games was considered in this paper. The brute force Nash equilibrium method for mixed strategies, known in case of N = 2, was successfully generalized. Computational complexity of this algorithm is unacceptable; this algorithm is reduced to solving exponentially increasing (depending on the number of strategies) number of completed linear systems, where the number of variables also exponentially depends on N. The new playing equilibrium algorithm based on the methods of linear programming and duality theory was proposed in this work. The algorithm was developed with the use of a more simple auxiliary coalitionfree game introduced by means of some problem of mathematical programming. An example of the numerical solution of a 3person game is given in the article.
Evaluation of conditional distribution of failures over the Poissonian flow with the use of the binomial law
# 08, August 2013 DOI: 10.7463/0813.0586737 This paper presents results of the evaluation of conditional distribution of failures over the Poissonian flow by the binomial law. The determined assessment allows one to build new decision rules for testing the null hypothesis of correspondence of failure intensity for a component item’s type with a group of such items collected on the principle of uniformity of a manufacturing technology and similarity of application domains. The authors also give an example of using this estimation for testing the null hypothesis of the correspondence of the failure intensity for a component item’s type with the mean group failure intensity in case of an alternative hypothesis, assuming that the failure intensity of the type is larger than the mean group one.
Aeronautical and Rocket Space Engineering
Development of mathematical and algorithmic support for determination of internal stresses in thin reflectors made of carbonepoxy composite during the technological process of manufacturing
# 08, August 2013 DOI: 10.7463/0813.0612095 The main stage of manufacturing precision reflectors is hardening of polymeric matrix which determines the final geometric shape of a product as well as its characteristic. Often, this process takes place in a rigid tool set which restraints changes in the geometric shape. In this connection, during the specified process internal technological stresses appears in the reflector’s material; these stresses could influence precision geometry. This article concerns development of mathematical and algorithmic support for determination of internal stresses and optimization of geometric models in the "reflector – snap" system.
Main approaches to formation of a thermal vacuum test program of precision mirror reflectors of space antennas
# 08, August 2013 DOI: 10.7463/0813.0612062 An obligatory element of mirror space antennas is a reflector which is a thinwalled shell of a parabolic or hyperbolic form. When a spacecraft enters the area of the Earth's shadow, temperature changes may cause temperature deformations; this may lead to distorting the shape and interfering with radiocommunications. For this reason, design decisions regarding mirror reflectors of space antennas must be confirmed by ground tests. A new method for the thermal vacuum test of a fullscale precision space reflector made of carbon fiberreinforced plastic was proposed in this work. Stability of the reflector’s shape within a wide range of temperatures was estimated by a contactless method; this method is based on heating of a reflector with a solar radiation simulator in a vacuum chamber with its walls cooled by liquid nitrogen.
Estimation of diamondlike protective coatings resistance to highenergy ion impact
# 08, August 2013 DOI: 10.7463/0813.0605449 This work deals with the possibility of using diamondlike coatings as protective layers applied to structural elements of a spacecraft. A technique for evaluation of thin coatings resistance to effects of ion radiation with the use of a focused ion beam was described. Results of stability studies of samples of diamond coatings on a substrate made of monocrystalline silicon using the specified method are presented in this paper. The structure and mechanical properties of the coatings were investigated; the coefficient of diamondlikeness was also determined. It was shown that the resistance of coatings is greater than the resistance of a silicon substrate by not less than 2.5 times. A relation between the resistance of coatings to highenergy ion impact, the degree of diamondlikeness of a coating and its microhardness was established.
Numerical modeling of vortex nonsteady flow field of viscous gas and acoustic characteristics based on the open source project for calculating the flow around aircraft
# 08, August 2013 DOI: 10.7463/0813.0605410 This paper shows the possibility of using the open source CFD software package OpenFOAM and developed methods for calculating unsteady vortex flow fields and acoustic fields in studying the flow around aircraft. Numerical calculations of aerodynamic characteristics of an airbrake mounted on the fuselage of an aircraft were conducted. A hybrid model of turbulence using RANS and LES approaches was defined. Curle’s acoustic analogy was used for calculation. Flow fields of the aircraft and acoustic performance were obtained. Pulsations acting on the tail fin induced by an airbrake were also analyzed. It was determined that pulsations of a lateral force on the fin of an aircraft caused by airbrake was 6 times more than pulsations in absence of the airbrake; and the sound pressure level was more than 50 dB.
Instrument Engineering, Metrology and InformationMeasuring Devices and Systems
Selection of lasers for increasing the range of onboard laser ranging systems of space vehicles
# 08, August 2013 DOI: 10.7463/0813.0609292 The purpose of this paper is to analyze possibilities and select laser sources for onboard laser ranging systems (LLS) of space vehicles designed to locate by a diffusely reflected signal and corner reflectors (CR). Characteristics of semiconductor, solidstate and fiber lasers were presented. Energy evaluation of range capability of onboard LLS in pulsed and continuous radiation modes using lasers of different types was conducted. It was shown that increase in range capability of onboard LLS by a diffusely reflected signal up to 10 km was provided with the use of fiber lasers, and for the range capability of more than 10 km usage of solidstate lasers was required. Influence of corner reflector parameters on the range capability of LLS was estimated. The obtained results could be used in development of onboard LSS for innovative space vehicles.
Some features of calculating the response of contact target sensors of fuses
# 08, August 2013 DOI: 10.7463/0813.0605972 In order to determine the initial stage of the interacting process between an explosive item and an obstruction, which is the most important for operation of contact target sensors (CTS), the author proposes two approaches to approximation of initial force characteristic of an obstruction; they were a piecewise function and a dependence of the explosive item’s cross sectional area on displacement. In this process, empirical formulas for the full path of an explosive item’s punchingin into an obstruction were used along with some experimentally derived facts. An example of calculating the response of the cluster ammunition element’s CTS was given. The author considers a possibility of using an integrating type of CTS as a means of measuring the explosive item’s speed after piercing an obstruction and filtering the imposed oscillations.
Comparative analysis of input signal power of laser systems for target location and ultraviolet vision
# 08, August 2013 DOI: 10.7463/0813.0587120 This paper presents results of a comparative analysis of input signal power of laser systems for target location and ultraviolet vision. It was shown that the spectral band of 300400 nm is promising for laser systems of the ultraviolet range operating in the earth atmosphere. Within the spectral band of 300400 nm coefficients of ground reflection have greater values, and coefficients of atmospheric attenuation have smaller values then they do within the spectral band of 200300 nm. The closer the wavelength gets to the value of 300 nm, the less background sun noise becomes.
Informatics, Computer Science and Management
Gametheoretic approach to risk assessment and vulnerability detection in information networks
# 08, August 2013 DOI: 10.7463/0813.0630132 In this paper a mathematical model based on directed graphs was presented. This model allows one to apply a quantitative approach to risk assessment and vulnerability detection in information networks, which is an important step during the security system design. A utility function and a heuristic for informed memorybounded search SMA* algorithm were also proposed. These results could be used for security audit and countermeasures planning.
Optimization technique of preventive replacements in the task of planning the repairer’s production cycle
# 08, August 2013 DOI: 10.7463/0813.0615305 This paper examines the operating reliability of motor vehicles. It was shown that the structure of maintenance operations and repair influences the cost of performance assurance. A method of preventive replacements was proposed in this work; this method transfers part of potential repair operations to the scheduled maintenance. Such decision contributes to increasing the operating reliability and the scheduled maintenance’s price. An optimization model, which allows one to determine the rational amount of preventive replacements, was also proposed in this work.
Technology of complex research of energy sector functioning in emergency situations with the use of Bayseian networks
# 08, August 2013 DOI: 10.7463/0813.0603646 In this paper the author proposes a technology of organization and execution of computational experiments in the field of energy security with the purpose of analyzing complex scenarios of emergency situations. This technology is based on application of intellectual research support within integrated ITenvironment and integration with Bayesian networks tool for modeling energy security threats. An example of a naturallyemerging threat of cold snap in the Central interconnected power system was also described. The presented technology gives a new opportunity in describing energy security threats; this is obtained due to the joint use of intellectual technologies for generation of computation scenarios (at qualitative level) and further transition to a traditional quantitative research.
Experiments with teaching of recognition methods for road signs with the use of synthetic data
# 08, August 2013 DOI: 10.7463/0813.0603378 This article considers the task of traffic sign recognition with learning from synthetic data. The method for synthetic dataset generation from one traffic signs pictogram for each class was described. The authors proposed a method for traffic signs segmentation and classification; the method is based on the nearest neighbor search in the space of gradient features derived from synthetic data. The proposed method was evaluated on databases from three different countries – Germany, Belgium and Sweden. A comparative analysis of classification accuracy of the proposed method with training from synthetic and real data was carried out.
Dodecapod’s movement algorithm within a linear cylindrical tube of variable crosssection
# 08, August 2013 DOI: 10.7463/0813.0587740 A dodecapod is a onesection parallel manipulator which could be considered as an evolution of the wideknown hexapod, or the Stewart platform. The idea of a dodecapod was proposed by prof. S.N. Sayapin in 2012. In this article the authors consider one of the dodecapod’s functional capabilities: movement within a linear cylindrical tube of uniform and variable crosssections. A design model of the dodecapod was presented in this paper along with propagation conditions for dodecapod’s movement within the tubes and the algorithms of changing the lengths of dodecapod’s rods, which make its movement possible. The presented results allow to draw a conclusion that a onesectional parallel manipulator based on a dodecapod could be applied to creation of mechanisms for execution of technological operations in linear cylindrical tubes of uniform and variable crosssections.
Analysis of University’s corporative network traffic by the methods of nonlinear dynamics
# 08, August 2013 DOI: 10.7463/0813.0587054 Results of calculations of incoming and outgoing traffic’s dynamic characteristics were presented in this paper along with the distribution of hardware capacities by the example of the university’s corporate network server. Lyapunov and Hurst exponents, which characterize chaotic and fractal properties of the processes, were evaluated for network traffic. Traffic’s phase diagrams were investigated and, for the first time, appearance of attractors was revealed; these attractors allow one to conduct a more detailed analysis of the impact of load on the network’s traffic capacity. A selfsimilarity was found for all the processes; this fact confirms the possibility of using fractal models for working with data, including solving urgent problems of predicting behavior of the time series.
Special AWS for designing software for navigation complexes and aerial surveillance
# 08, August 2013 DOI: 10.7463/0813.0585918 This paper is based on the results of investigations of computeraided design facilities for systems software and software for terrestrial and onboard facilities of aerial surveillance and Earth remote sensing. The article presents a review of typical airplanes used for carrying navigation equipment and aerial surveillance along with the investigation of intelligence equipment, key factors of airplane navigation and hardware properties which determine the quality of intelligence data obtained in different modes of aerial surveillance, special features of intelligence data preprocessing inflight, peculiarities of ground information system for processing intelligence data and preparing intelligence reports. Configuration of a special AWS was justified.
Numerical solving static equations in a charged gas flow model with the use of Haar wavelet method
# 08, August 2013 DOI: 10.7463/0813.0583405 This article considers the Cauchy problem for the second order automodeling nonlinear ordinary differential equation in the problem of twofluid plasma motion. An algorithm for solving this problem with the use of Haar wavelet method was described. A numerical experiment showed that Haar wavelet method is more accurate than the fourth order RungeKutta method for few collocation points in problem 1 with a known analytical solution. In problem 2, where the exact solution is unknown, relative error between numerical solutions by Haar wavelet method and RungeKutta method tends to decrease with the growth of the number of collocation points.
Estimation of working precision of the method of automated identification of lexical items by using virtual texts
# 08, August 2013 DOI: 10.7463/0813.0583389 This article describes a method for analyzing working precision of algorithms of automated identification of lexical items of natural language word forms on the basis of virtual texts. Estimation of working precision of this complex automated method was carried out with lexical items of Russian word forms. Expediency of applying this comprehensive solution to the problem was proved. The nature of identification errors was revealed, and on the basis of the results of the conducted analysis recommendations were given on modification of the proposed method in order to increase accuracy of automated identification of Russian lexical items.
Approach to calculation of weighting coefficients of experts’ rank assessments when selecting a development option for an information system
# 08, August 2013 DOI: 10.7463/0813.0580272 An approach to calculation of weighting coefficients of experts’ rank assessments, which is aimed at improvement of processing results of an expert survey, was proposed. This approach was designed to increase the concurrence level of experts’ opinions within a formed working group. Weighting coefficients are calculated either considering known numerical values of experts’ experience levels or on the basis of experts’ rank assessments produced from a test assignment. Recommendations on formation of a competent working group of experts who belong to the same school of sciences, as well as rules for using the normalized rank system, are at the heart of this approach. An example that illustrates efficiency of the proposed approach was presented in this paper.
Mechanics
Influence of permeability inhomogeneity of deboosters on characteristics of plain aerostatic bearings
# 08, August 2013 DOI: 10.7463/0813.0611443 A mathematical model was developed for plane aerostatic bearings with porous deboosters; this model allows to determine the main performance characteristics such as damping stiffness of load capacity in linear and angular directions and a consumable air flow. Experimental determination of permeability inhomogeneity for porous graphite deboosters was conducted. Influence of permeability variation on characteristics of an aerostatic bearing was evaluated by means of calculations with maximum and minimum values of the permeability index. This influence appeared to be smaller with a constant aerostatic gap than with constant load. On the basis of the obtained results, recommendations on manufacturing plane aerostatic bearings were given.
The phenomenon of crawling and peculiarities of motion of a rotor with pendular selfbalancers
# 08, August 2013 DOI: 10.7463/0813.0603673 Results of the investigation of a new phenomenon in revolving of a rigid rotor in elastic supports with four pendular selfbalancers were presented in this article. The rotor revolves with a working speed but pendulums move with a rotation frequency which is equal to one of two critical rotor’s velocities; these velocities are conditional upon, respectively, linear or angular parameters of motion. An experimental apparatus used for obtaining the dynamical phenomenon was described; data on physical parameters of the system were also provided. A current hypothesis of emergent interactions as the fundamental of creating a mathematical model of the processes of locking was proposed. A procedure of creating a mathematical model for a system with eight degrees of freedom was also proposed. Properties of dynamical links between partial systems which could be set only for stated forms of selforganization of motion of a group of freely suspended pendulums were discussed.
Metallurgical Engineering
New criterion for estimating probability of formation of microporosity in castings
# 08, August 2013 DOI: 10.7463/0813.0585558 This paper presents a new dimensionless criterion of formation of microporosity, which considers a set of essential technology factors, including atmospheric and metallostatic pressure, alloy’s gas saturation. The criterion is based only on the measured or controllable parameters and does not demand additional experimental data. A feature of the criterion is absence of the radius of a critical germ of a micropore. An estimation of the distance between secondary axes of dendrites is used instead. The criterion is recommended for using in systems of simulation of casting hardening for more accurate prediction of formation of microporosity.
Behaviourial Sciences
Activity and personal criteria of professional elitism in the sphere of technology
# 08, August 2013 DOI: 10.7463/0813.0589233 The article presents criteria of professional elitism in the field of technology, developed in accordance with the author's concept. The aim of the research was to identify practical and personal features of professional elitism, reflecting the main functionalandrolebased content of professional activity of elite specialists in the sphere of technology, as well as professionally important personal qualities of an elite specialist that are manifested in the process of professional activity and communication in social and professional environment. On the basis of a theoretical analysis major activity and personal criteria of professional elitism, characterizing motivational and operational readiness of a specialist for professional fulfillment in the role of an elite professional of a technical activity profile were identified.
Armament Theory, MiliteryTechnical Policy, Weapon System
Influence of contact between detonation products and a metal disk by the value of its meridional opening angle
# 08, August 2013 DOI: 10.7463/0813.0602548 Problems and solutions arising during creation of a mathematical finite element model of homemade explosive devices (HEDs) were described. The distinct feature of this model is that it relies on the Lagrangian and Eulerian approaches in order to describe the expansion of the explosive charge’s detonation products and deformation of HEDs’ metal parts. The author determined influence of the type of mathematical contact between interactive media on the accuracy of values of the colatitude opening angle of fragments (fragmentation field), which are formed as a result of an explosion of the HED. The obtained results could be useful for criminalists and help them to carry out a comprehensive judicial technical expertise of HEDs’ explosion.



