Vol 9, No 1-4 (2015)
- Year: 2015
- Articles: 14
- URL: https://journals.eco-vector.com/2074-0530/issue/view/3724
Articles
The effect of the magnetic field on formation and development of microcracks while friction
Abstract
The formation and development of cracks in the sample of ferromagnetic material in magnetized condition were researched. It was shown that magnetic state of material of friction surface most substantially influences the process of its brittle or quasibrittle fracture if cracks open perpendlcularly to magnetization vector. The criterion of unintentional growth of crack in magnetic field was established.
Izvestiya MGTU MAMI. 2015;9(1-4):5-9
5-9
Computer-aided design of gas turbine engines rotors
Abstract
The technology of the optimal design when designing the structure of the rotor disc for turbomachines is showed. The features of the organization of computer-aided design of gas turbine engine rotor are considered. The calculations of gas turbine engine rotor parts optimal form were made. Structural optimization (shape optimization) was applied to optimal design of compressor disk depending on various factors of loading and optimization criteria.
Izvestiya MGTU MAMI. 2015;9(1-4):10-20
10-20
Mathematical methods for the analysis of migration processes on the basis of demographic data
Abstract
The problem of mathematical analysis of demographic data was investigated for data, where information on migration flows is taken into account implicitly. Regression techniques, neural networks and stochastic analysis were used for the mathematical analysis of demographic processes. Two age groups were considered: young (0 - 39 years) and elderly (40 - 70 years). While development of stochastic models the theory of Markov chains and transition matrix were used. The parameterization and model identification were conducted according to Rosstat data.
Izvestiya MGTU MAMI. 2015;9(1-4):21-25
21-25
Possibility of existence an exact solution of Navier-Stokes equations on example of calculation the initial section in a circular tube
Abstract
The solution of the equations of motion of Newtonian fluids (Navier-Stokes equation) in vector form, containing a projection of speed and rotor speed, is considered. There was analyzed the axisymmetric laminar flow of a viscous incompressible fluid in the initial section of entrance to the circular tube, where the flow is described by only two velocity components.
Izvestiya MGTU MAMI. 2015;9(1-4):26-41
26-41
The requirements of modern methods of calculating reserves for static strength to mechanical and strength characteristics of liquid-propellant rocket materials
Abstract
The article describes the main aspects of the static tensile testing of round uniaxial samples and processing gained results with the aim of obtaining the mechanical and strength characteristics of materials, which are used for further obtaining of criteria for the destruction of structures. The paper addresses some problems of numerical modeling of the mechanical behavior of test specimens, as well as gives recommendations on the use of standard characteristics in the construction of chart of material properties.
Izvestiya MGTU MAMI. 2015;9(1-4):42-48
42-48
49-55
Modeling the simplified circuit of testing assemblies of armored equipment at lateral blasting
Abstract
When studying the stability of armored equipment assemblies at lateral blasting it is necessary either use a real object, or apply special stands. These tests are very expensive and tend to cause significant structural damage. The article presents calculations of simplified scheme for lateral blasting. Lateral blasting is by an equivalent by impact vertical blasting with reduced distance. The proposed approach can significantly reduce the cost and simplify the experiment, which reduces the amount of explosives and allows multiple-choice tests.
Izvestiya MGTU MAMI. 2015;9(1-4):56-59
56-59
Strength numerical and experimental investigation of bolted connection of parts under dynamic impact
Abstract
The paper presents the results of numerical and experimental investigation for evaluation of strength of bolted connection of parts of armored equipment under dynamic impact, namely, high-speed impact pressure from the explosion of ammunition (TNT blocks, grenades). The comparison of calculated and experimental data was made.
Izvestiya MGTU MAMI. 2015;9(1-4):60-63
60-63
The stability of elastoplastic shells under proportial subcritical processes of combine loading
Abstract
The problem of bifurcation of thin-walled cylindrical shell under proportional subcritical loading by axial compressing force, torque and internal stress in the deviatoric space by A. A. Ilyushin's strain was investigated. The relationship of stress and strain is adopted in accordance with the defining relations of the above-mentioned hypothesis. For determinative functions of plasticity there were used approximations, which were offered by V. G. Zubchaninov.
Izvestiya MGTU MAMI. 2015;9(1-4):64-69
64-69
Fluctuations in systems with a discrete number of degrees of freedom with dry friction
Abstract
The approximate analytical for solving problems of forced oscillations f mechanical systems with discrete degrees of freedom, taking into account dry friction forces. Dry friction is replaced by an equivalent viscous resistance. For this purpose, the method of own functions for systems with discrete degrees of freedom is used to allow replacing the original system with some equivalent system. Thus there is postulated the equality of frequencies of original and present systems. The proposed method is illustrated by the example of the oscillating system with two degrees of freedom.
Izvestiya MGTU MAMI. 2015;9(1-4):70-73
70-73
Two-step algorithm of the signal processing correlation in passive radar system, which operates on signals from third-party sources
Abstract
The article discusses the correlation algorithms of signal processing in passive radar systems using the signals from third-party sources. A two-stage algorithm for correlation processing, which can significantly reduce the computational cost, is proposed. The calculation of the computational complexity of the proposed algorithm and the accuracy of estimation of signal parameters on the signal-to-noise ratio are provided.
Izvestiya MGTU MAMI. 2015;9(1-4):74-80
74-80
Method of suppression of the direct signal illumination in multi-station passive radar using the signals from third-party sources
Abstract
The article discusses the analog methods of suppressing the signal of the transmitter in the receiving channel in passive radar systems using the signals from third-party sources. An analog method of compensation transmitter signal in the receive path for multi-position passive radar systems is proposed. The results of experimental verification of the proposed method are shown.
Izvestiya MGTU MAMI. 2015;9(1-4):81-87
81-87
88-91
Limiting parameters of forming round steel sheet, locally loaded by combined profile punch
Abstract
There are shown the results of application of an axisymmetric rigid-plastic finite element membrane model to the analysis of a circular steel sheet stretching process under action of a punch with profile, which consists of two circular arcs with small radii. The failure of the deformed shell is computationally revealed in the form of strain localization.
Izvestiya MGTU MAMI. 2015;9(1-4):92-96
92-96