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Gulyayev V.I.,National Transport University | Shlyun N.V.,National Transport University
Journal of Natural Gas Science and Engineering | Year: 2017

Currently, with advent of new techniques of drilling deep and curvilinear bore-holes, the conditions of their drivage become more drastic and severe. In these cases, redistribution of gravity, contact and friction forces acting on a drill string can give rise to emergency situations, one of which is the loss of its equilibrium stability and buckling. This phenomenon has been studied comprehensively as applied to the inclined rectilinear holes, but it is still understood incompletely if the drill string buckles in the channel of a curvilinear hole. In this paper, a new formulation of the problem on critical buckling of drill strings in inclined holes with variable geometry is devised through the use of the theory of curvilinear flexible rods. The stated eigen value problem is demonstrated to be singularly perturbed, that is the reason why its solutions have the shapes of localized harmonic wavelets. The computation results testify that the buckling phenomenon manifestation is determined by the relation between the influences of gravity and friction forces dictated by the angle of the bore-hole inclination. The peculiarities of the drill string behavior associated with the values of critical loads, pitches of the buckling wavelets, their widths and places of their localization in the rectilinear and curvilinear inclined bore-holes are discussed. © 2017 Elsevier B.V.


Danilov E.,National Transport University
Journal for Geometry and Graphics | Year: 2014

In 3D modeling CAD users often face problems that can be success-fully analyzed and solved only by the methods of Descriptive Geometry. One such problem is considered in this paper: the construction of structural elements of machine parts known as stiffening ribs. In addition, a possible geometry of ribs is analyzed and a review is performed of tools for its modeling available in up-to-date CAD packages. Some features are shown that are useful in representing parts with ribs in technical drawing manuals. An innovative approach is developed for educational purposes. © 2014 Heldermann Verlag.


Omara A.M.,Tanta University | Sleptsov M.A.,National Transport University
Proceedings of the 2017 IEEE Russia Section Young Researchers in Electrical and Electronic Engineering Conference, ElConRus 2017 | Year: 2017

Battery-powered electric vehicle (EV) is considered as a promising solution for environmental pollutions and energy crises. Besides, the advances in traction motors and battery technologies allow the development of efficient, reliable and economical electrical propulsion system (EPS) for battery-powered EVs. Where, permanent magnet synchronous motor (PMSM) is mostly used in EVs because of its good performance compared to other used motors. Moreover, Lithium-ion batteries are mostly used to provide the motoring power due to their high energy densities and long lifetimes. In this paper, the driving performance of a battery-powered EV powertrain system is evaluated. The proposed EV propulsion system implements PMSMs as its main traction system. The design and simulation results of the proposed powertrain system are presented. A co-simulation platform based on AVL-Cruise and Simulink is established, and a simulation of the whole EV model is conducted. Using rule-based power management and control (PMC) strategy to manage and control the power flow between rear and front EV drive systems. Vehicle performance under the new European driving cycle (NEDC) is calculated and presented in the simulation results to specify the potential of the proposed system. The simulation results demonstrate that the proposed powertrain system match the design specification of EV dynamic performance and driving range capability. © 2017 IEEE.


Zinko R.,National Transport University
Vibrations in Physical Systems | Year: 2014

The use of graphs for the research of a rotor crush machine work on elastic foundation is offered. For machines the structure graph of its design is being written. The graph of levels structure of the generalized coordinates of mathematical model is being formed on the basis of structure graph of machine design. It allows building of the mathematical model, which describe the physical processes of the machine work quickly and qualitatively. © by Poznan University of Technology, Poznan, Poland 2014.


Grigorenko A.Y.,Ukrainian Academy of Sciences | Loza I.A.,National Transport University
International Applied Mechanics | Year: 2013

The propagation of nonaxisymmetric waves in layered hollow cylinders with radially polarized piezoceramic layers is studied. The associated problem is solved with an effective numerical-analytic method. The original three-dimensional problem of electroelasticity for partial differential equations is reduced to a boundary-value eigenvalue problem for ordinary differential equations by representing the components of the stiffness tensor, displacement vectors, electric-flux density, and electrostatic potential as standing circumferential waves and traveling axial waves. The problem is solved with the stable discrete-orthogonalization method in combination with the incremental search method. The dispersion equations are numerically analyzed over a wide range of variation in the geometrical characteristics of cylinders with piezoceramic layers © 2013 Springer Science+Business Media New York.


Vakulenko I.O.,National Transport University
Materials Science | Year: 2016

It is shown that the intense cooling (with rates of 2–9°C/sec) of wheel rims after their hot rolling in a rolling mill increases the yield limit and the ultimate strength of the metal. It is also established that, in the absence of supersaturation of the solid solution with carbon atoms in the course of this kind of cooling, the mechanical properties of carbon steel are determined solely by the internal stresses caused by the phase hardening of ferrite in pearlite and the state of ferrite–cementite boundaries. © 2016 Springer Science+Business Media New York


Khoroshev K.G.,National Transport University
International Applied Mechanics | Year: 2010

Generalized complex potentials, their expressions for a domain with elliptic holes, and the discrete least-squares method are used to analyze the generalized plane electroelastic state of a piezoelectric plate having holes and cracks with electric potentials applied to their boundaries. There are no mechanical loads. A numerical analysis is conducted. The effect of the applied voltage on the electroelastic state of the plate is examined © 2010 Springer Science+Business Media, Inc.


Gladush V.D.,Dnipropetrovsk National University | Galadgyi M.V.,National Transport University
General Relativity and Gravitation | Year: 2011

We propose the method of investigation of radial motions for charged and neutral test particles in the Reissner-Nordström field by means of mass potential. In this context we analyze special features of interaction of charges and their motions in General Relativity and construct the radial motion classification. For test particles and a central source with charges q and Q, respectively, the conditions of attraction (when qQ > 0) and repulsion (when qQ < 0) are obtained. The conditions of motionless test particle states with respect to the central source are investigated and, in addition, stability conditions for such static equilibrium states are found. It is shown that stable states are possible only for the bound states of weakly charged particles in the field of a naked singularity. Frequencies of small oscillations of test particles near their equilibrium positions are also found. © 2011 Springer Science+Business Media, LLC.


Gulyayev V.I.,National Transport University | Hudoly S.N.,National Transport University | Glovach L.V.,National Transport University
International Journal of Solids and Structures | Year: 2011

The problem about identification of resistance forces acting on a drill column moving in an inclined bore-hole is stated. It is supposed that the well trajectories can have geometrical imperfections in the shape of cylindrical spiral or plane cosinusoidal curves. The system of ordinary differential equations is derived on the basis of the theory of curvilinear flexible elastic rods. It permits one to describe static effects of the drill column bending accompanying the processes of its raising, lowering and rotating inside the bore-hole. Through the use of this system the direct and inverse problems of the drill column deforming are formulated for calculation of internal and external resistance forces acting on the drill column tube. The methods for numerical solution of the constructed equations are elaborated. With their use the phenomena of the drill columns motion and their frictional seizure inside the bore-holes are simulated for different geometrical imperfections and relations between the velocities and directions of their rotation and axial motion. © 2010 Elsevier Ltd. All rights reserved.


Gulyayev V.I.,National Transport University | Borshch O.I.,National Transport University
Journal of Petroleum Science and Engineering | Year: 2011

This paper considers the problems on investigation of the dynamic bending of elongated drill string tubes studied with allowance made for destabilizing effects of the longitudinal non-uniform preloading, action of torque, inertia forces of rotation and internal flows of washing liquid (mud). As a result of the completed analysis, natural wave and vibration modes are constructed, their frequencies are calculated. It is shown through the study of appropriate dispersion equations that free bending vibrations of unbounded rods can be realized only in the modes of regular dextral and sinistral spiral waves propagating with different velocities in different directions. The modes of free vibrations of the bounded drill strings possess more complicated irregular spiral shapes. © 2011 Elsevier B.V.

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