Другие журналы

scientific edition of Bauman MSTUSCIENCE & EDUCATIONBauman Moscow State Technical University. El № FS 77  48211. ISSN 19940408
# 03, March 2013
Machine Building and Engineering Science
Comparative analysis of metalcutting equipment under production engineering
# 03, March 2013 DOI: 10.7463/0313.0541242 The article deals with analysis of general approaches used to formalize the procedure of selecting metalcutting equipment. The author emphasizes importance of the discussed problem for choosing metalcutting machine and analyzes general conditions of selecting metalcutting equipment. It is shown that the process of selecting metalcutting equipment refers to the multicriterion optimization problem in the area of decisionmaking process. Theoretical prerequisites for formalizing main stages of selecting technological equipment are determined. Methods of alternative comparative analysis, which can be used to solve the specified problem, are analyzed. The author proposes a general algorithm for choosing the preferred model of metalcutting equipment that meets the predetermined production condition and limitations.
Investigation of stability of the combined process of drawing and oncoming flanging at stamping rings with double walls
# 03, March 2013 DOI: 10.7463/0313.0541172 The authors investigate the influence of correlation coefficients of drawing and flanging on stability of the combined process of obtaining profile rings with double walls. Finite element method is used. To assess the stability, wall height is recorded. It was determined that when drawing and flanging coefficients change there is a critical ratio of the coefficients at which the process loses stability. Relative thickness of a work piece has a determining influence on stability. Application range of this combined process expands with the increase in relative thickness, with the decrease in the punch radius of curvature and with the use of stainless steel.
Light emission and electrical process in the cavitating flow of mineral oil
# 03, March 2013 DOI: 10.7463/0313.0535547 During the research of cavitation processes in the mineral oil flow inside a transparent model of an orifice restrictor steady light emission in the blue range of the visible colour spectrum was revealed. Intensity of light emission grew as the flow velocity increased. Upon reaching the threshold value of the flow velocity, light emission became pulsatile; and when velocity continued to grow, emission stopped. Experiments revealed the presence of mineral oil of intensive electrical processes in the cavitating flow. The created experimental setup allowed to make a quantitative assessment of electric processes and to record the dynamics of light emission. Hypothesis that explains the physics of discovered effects was proposed along with assumptions about possible influence on the working liquid for hydraulic drives and wall materials of narrow channels of hydro automatic equipment elements and devices.
Constructional Material Processing in Machine Building
Influence of a shaped blank on force power characteristics of manufacturing wrapped angular contact metalfluoroplastic slider bearings
# 03, March 2013 DOI: 10.7463/0313.0544282 In this article the authors cover improvement of manufacturing metalfluoroplastic bearings from a parent sheet. The distinct feature of this work is producing a liner with a flange from the parent sheet. The authors revealed a procedure of forming a bearing flange using finite element simulation. Zones of nonuniform deformation were found. These zones can reduce the product quality. It was proposed to change the shaped blank form in order to reduce the zones of nonuniform deformation and relieve the metal flow. Simulation of the deformation process with the use of the new shaped blank demonstrated decrease in energypower characteristics of the process and increase in uniformity of the deformed condition. The results of the research will help to improve the quality of metalfluoroplastic bearings used in aviation.
Setup for studying the process of cutting materials at low cutting speeds
# 03, March 2013 DOI: 10.7463/0313.0541420 In this article the authors describe the construction and operation of a technological laboratory setup for studying the process of chip formation during cutting at micro speeds; this setup was developed at Bauman MSTU. This setup was developed on the basis of a large Zeiss engineer microscope. The setup includes a special drive for moving a work piece relative to a hardmounted tool; it also includes an automated photo micrographic attachment for recording separate stages of deformation and destruction of a material of the layer being cut, and a specially designed dynamometric device based on the elastic and electrical operating principle for determining the cutting force components. This set of devices allows to investigate and record separate stages of the chip formation process in more detail and to estimate their influence on formation conditions and quality of machined surfaces.
Power Machine Building, Metallurgical Machine Building and Chemical Engineering
Modeling and calculating processes of induction heating for press equipment during manufacture of rubber products
# 03, March 2013 DOI: 10.7463/0313.0541632 The authors consider mathematical models of induction heating of a single plate in a hydraulic vulcanizing press for the initial warmup period and the period of maintaining the operating temperature. They carry out a comparative analysis of an industrial experiment for studying the processes of heating and maintaining the temperature of the working surface of such a plate with the results obtained by solving models with the method of finite integral transformations and with the application of the finite element analysis. For the first time, the authors proposed a mathematical model of the "induction platemoldrubber product" system, a technique for approximate solving the model by the finite element method; the model is supposed to be used for solving the optimization problem of press design and molds design, molds positions between the heating plates. The results of solving this problem by the example of the industrial press are provided in this article.
Simulation of air pressure losses in the finned tube bundle of an air condenser
# 03, March 2013 DOI: 10.7463/0313.0544307 The authors describe an approach to numerical simulation of air flows in the box of an air condenser by replacing the tube bundle geometry with an anisotropic filter  that is, with a selected area in the computational model with the given hydraulic resistance. Hydraulic characteristic of the finned air condenser’s heatexchange surface was determined by using CFD (Computational Fluid Dynamics) along with FlowVision, Phoenics and OpenFoam software in order to set the properties of the anisotropic filter correctly. The obtained results allow to simulate a threedimensional air flow inside the box of an air condenser and determine parameter fields of the flow at the input and output of the tube bundle without direct numerical simulation of the air flow in the intertubular space.
Transportation, Mining and Construction Machine Building
Subharmonic oscillation damping in hydromechanical transmission
# 03, March 2013 DOI: 10.7463/0413.0548552 Results of an experimental investigation of dynamic loading of a transport machine hydromechanical transmission are described in the article. On the basis of comparing resonance oscillations frequencies of dynamic torque with frequencies of diesel perturbations, the authors proposed and hypothesis substantiated a hypothesis of implementing subharmonic resonances in a mechanical system which has essentially nonlinear elastic response. Theoretical study of dynamic processes in the system using linearization of the nonlinear characteristic by means of the harmonic balance method was carried out. The obtained analytical dependences allowed to tune out a nonlinear system from resonance by varying the characteristics of an elastic vibration damper. The authors also provide a variant of constructive implementation of a matching gear of hydromechanical transmission using a new type of vibration damper, as well as results of an experimental evaluation of effectiveness of the developed design solutions.
Features of building finite element models of cabins for passive safety studies under the impact according to UNECE Regulations № 29
# 03, March 2013 DOI: 10.7463/0313.0542301 The authors developed rational finite element models of truck cabs for studies of passive safety under impact loading executed in accordance with the current standard of passive safety. The obtained results were estimated with consideration of errors and efforts; the problem was solved by means of FEM software (ANSYS and LSDYNA). The influence of structural factors on the solution (doors, panels, trims, etc.) was also investigated. Calculations based on the finite element method provide one with complete information on the process of emergency loading required for estimating passive safety of truck cabs.
Aeronautical and Rocket Space Engineering
Swaging of extremely thinwalled pipe shells
# 03, March 2013 DOI: 10.7463/0313.0542068 This article covers problems relative to reduction of extremely thinwalled pipe shells in a rigid die with the use of a tooling shell. This problem was solved by an engineering method of prediction based on the stress equilibrium equation, approximate plasticity condition and the Laplace equation of momentless theory of shells. For calculation of this process, mathematical expressions were obtained and verified experimentally. Experimental researches were conducted with the use of tube shells made of aluminum alloys. It was found that contact friction between an extremely thinwalled shell and a tooling shell influence the process.
Determining constructivetechnological parameters of polyamide filmwound pipelines
# 03, March 2013 DOI: 10.7463/0313.0541990 The authors consider application of polyamide films with fluoroplastic coating for production of filmwound pipelines of aircraft power plants which use cryogenic propellant components. Design problems of multilayer covers for straight and curvilinear pipelines made of polyamide films were considered; operating and kinematic parameters of spinning and heat treatment of pipelines were determined. The authors proposed a method of connecting the flange shank end of the pipeline with a film cover; specific geometrical dimensions were provided. Results of strength and leakproofness tests of pipe samples made of polyamide film PMF352 by inner pressure of liquid nitrogen are given in this article. Possibility of their usage in devices that operate on cryogenic fuel is described.
Calculation of loads on truss frames of launching plant units caused by gasdynamic and wind influence
# 03, March 2013 DOI: 10.7463/0313.0541205 This article describes how to set wind and gasdynamic loads on truss frames of units of a space rocket launching plant. For automating formation of nodal static loads in finite element software systems, the authors consider a distribution algorithm for nonuniform pressure of wind or the jet of a space rocket propulsion system on rod finite elements. In this paper the authors propose an algorithm for determining load values for a given crosssection plane of an axisymmetric gas flow. The proposed algorithms and mathematic models can be applied to all units consisting of truss frames. The obtained results were used for calculating bearing assemblies of the launching plant for the space rocket "Soyuz" under the influence of a gasdynamic jet propulsion of the space rocket "Soyuz2" at stage 1c.
Instrument Engineering, Metrology and InformationMeasuring Devices and Systems
Method of classification of oil slicks on the earth surface, based on detection of fluorescent radiation in five narrow spectral ranges
# 03, March 2013 DOI: 10.7463/0313.0539554 The article deals with classification of oil slicks on the earth surface. The authors provide experimentally obtained fluorescence spectra of pure oil and petroleum products; of various earth surfaces that are not polluted with oil; of oil and petroleum products spilled on various earth surfaces. It is shown that the use of the method based on detection of fluorescent radiation in five narrow spectral ranges allows to detect and classify oil slicks on the earth surface with probability of correct detection and correct classification close to one.
Informatics, Computer Science and Management
Synthesis of orientation mechanisms for the space observatory “Millimetron”. 2. Synthesis and optimization of a parallel multisectional manipulator for orientation of the space observatory “Millimetron”
# 03, March 2013 DOI: 10.7463/0413.0554360 This is the second paper in the series of four works dedicated to design of parallel mechanisms for orientation of the space observatory “Millimetron”. In this article the authors stated a problem of “Millimetron” observatory's antenna orientation with the use of a parallel hexapodbased multisectional manipulator. The manipulator was designed in Solid Works software package. The Manipulator's 3Dmodel created in NX5 with the use of “Kinematic Simulation of Mechanisms” software package is introduced in this work. Software for solving direct and inverse kinematic problems was designed. A model of the guided fivesection manipulator developed in MatLab Simulink software package is also described.
Analysis of stream ciphers by solving a system of algebraic equations
# 03, March 2013 DOI: 10.7463/0313.0546388 The authors research the method of algebraic attack on stream ciphers based on solution of algebraic equations. The method is applied to a stream cipher constructed according to the disposable pad scheme. The authors consider types of key stream generators needed to construct stream ciphers. The key stream is a pseudorandom bit sequence which is combined with the original message to get the ciphertext. The algebraic method of finding the key of the key stream is described in the article. A program that generates a key stream and a system of equations to analyze the stream cipher was developed. The authors found maximum parameters of the stream cipher, the analysis of which can be carried out by software in several first elements of the key stream, its output function and changes of memory state.
Method of multivariant evolutionary synthesis of models based on templates
# 03, March 2013 DOI: 10.7463/0313.0550970 The author describes an algorithm of a multivariant evolutionary synthesis which combines advantages of genetic algorithms and genetic programming, based on a sequential operator structure of chromosome and templates (patterns, skeletons) of algorithms and a given set of pairs of input  output data. Influence of many variants of estimating chromosomes and the degree of the template’s specialization on search algorithm efficiency in the evolutionary synthesis was investigated. The author obtained estimates of the algorithm complexity and compared them with ones for the standard method of the evolutionary synthesis; this comparison showed a significant (by several times) decrease in search time by using the multivariant evolutionary synthesis algorithm.
Rank analysis of random fields
# 03, March 2013 DOI: 10.7463/0313.0541592 In this article the process of twodimensional autoregression of (1,1) order is considered. Distribution of the renovating field of the autoregressive model is assumed to be unknown. The author found the asymptotically locally most powerful tests for verifying the hypotheses about coefficients of the autoregressive field, based on the approximate rank index marks. Estimation of the autoregressive model parameters based on the ranks of observation residuals was build. Consistency and asymptotic normality of these estimations was proved. The conclusion was drawn on the advantage of the constructed estimation over the least squares estimation if the renovating field has normal logistic and double exponential distribution, while rank index marks correspond to Gaussian density.
Mechanics
Comparative analysis of estimations of polycrystalline material’s effective thermal conductivity coefficient
# 03, March 2013 DOI: 10.7463/0313.0541029 The authors carried out a comparative quantitative analysis of mathematical models for estimating effective thermal conductivity coefficient of polycrystalline material which consists of chaotically oriented anisotropic crystal grains with identical crystal grid. Along with wellknown methods for generating mathematical models, approaches which allowed to obtain new calculating dependences were also considered. The upper and lower bounds for accepted values of this coefficient were obtained with the use of a dual variational formulation of a stationary thermal conductivity problem for a nonhomogeneous solid body. Formulas for calculating bestattested estimations were recommended. These formulas could be used for estimating electric conductivity of polycrystalline materials due to electro thermal analogy.
Improved formula for calculating coefficients of transfer matrix in statistical dynamics problems
# 03, March 2013 DOI: 10.7463/0313.0543198 In this paper the authors propose improved formulas for calculating coefficients of transfer matrix in the presence of damping. The authors consider a classical damping which means the damping matrix is proportional to the stiffness matrix. These formulas are designed for large finiteelement models. Preliminary determination of the lower bound for natural frequencies and oscillation modes is expected. Approximate formulas are used only to calculate coefficients of obtained bending modes. In the revised formula contribution of higher vibration tones is taken into account; corrections for both real and imaginary parts of coefficients of the transfer matrix were also found. Contribution of rejected vibration tones is considered to be static, but within a given range of frequencies in the lower part of the spectrum accuracy is quite acceptable, and the effect of correction is significant.
Stability and stabilization of equilibrium state of mechanical systems with redundant coordinates.
# 03, March 2013 DOI: 10.7463/0313.0541146 For mechanical systems with geometric constraints application of the Shulgin method for obtaining motion equations without joining factors, which is based on a simple derivation of constraint equations, is considered in this article. Obtained motion equations for holonomic system in redundant coordinates are a special case of the Voronetz equations for nonholonomic systems in case of integrable constraints. The method for using these equations is developed for stability and stabilization problems of the equilibrium position of systems with redundant coordinates. The proposed approach allows to use previously obtained results based on the theory of critical cases. The problem of nonasymptotic stability was tackled by reducing it to the LyapunovMalkin theorem of stability for a special case of several zero roots. In this paper, the authors prove that consideration of constraints on initial perturbations asymptotically stabilizes the equilibrium state despite formal reduction to a special case, if the number of zero roots of the characteristic equation is equal to the number of constraints and real parts of other roots are negative. Efficiency of this approach was verified by investigating the stabilization problem of the equilibrium state for real mechatronic workbench GBB1005 Ball&Beam Educational Control System.
Optics
Comparative analysis of numerical and algebraic methods of automated calculation of optical systems in the paraxial region
# 03, March 2013 DOI: 10.7463/0313.0548050 In this article the authors present an efficiency comparison of numerical and algebraic methods for solving polylinear model equations in order to determine an optimal algorithm of parametric synthesis of a centered optical system in Gaussian optics. The performance analysis was carried out with case studies of varying complexity that illustrate features of both methods. Generation of multilinear equations was produced in a semiautomatic mode while optical powers of components were considered to be unknown. Recommendations on usage of each method for the computeraided parametric synthesis based on results of comparative analysis are given.
Electrical Engineering
Simulation of a traction generator and its test bench
# 03, March 2013 DOI: 10.7463/0313.0542271 In this article the author proves expediency of application of a traction generator based on a ninephase synchronous electric machine with permanent magnets, closedcoil winding and an uncontrolled rectifier in a complete set of traction electric equipment of the supersize vehicles. By means of developed simulation models of a traction generator and a test bench, influence of switching processes in the generator rectifier on its static and dynamic characteristics was investigated. Analysis of obtained simulation results and results of development tests was carried out, and the obtained results are provided in this article. Recommendations on use of simulation models during designing and modeling of a combined action of the traction generator and internal combustion engine are drawn.



