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Perig A.V.,Donbass State Engineering Academy | Golodenko N.N.,Donbass National Academy of Civil Engineering and Architecture
Materials Research | Year: 2016

The present article is focused on a 2D computational fluid mechanics study of local viscous flow dynamics and the formation character of rotary modes of deformation during Equal Channel Multiple Angular Extrusion (ECMAE) of a polymer workpiece fluid model through a U-shaped die with parallel slants in channel intersection zones. The present local flow problem was experimentally analyzed using physical simulation methods and theoretically studied with numerical fluid mechanics techniques. The computational approach has been grounded on the numerical finite difference solution of the boundary value problem for the Navier-Stokes equations in the curl transfer form for the local viscous flow of incompressible Newtonian fluid through a U-shaped rectangular die with parallel slants. The derived research results allow us to draw a conclusion that the implementation of a geometric design of parallel slants within a 2-turn U-shaped die results in localization of the maximum tangential stresses within the workpiece volume to the vicinity of these parallel slants during ECMAE. Source


Perig A.V.,Donbass State Engineering Academy | Golodenko N.N.,Donbass National Academy of Civil Engineering and Architecture
Chemical Engineering Communications | Year: 2014

The present work is focused on a 2D fluid dynamics description of equal channel multiple angular extrusion (ECMAE) or equal channel multiple angular pressing (ECMAP), using a numerical mathematical simulation for viscous flows of physical polymeric materials models through a die with a movable inlet wall. A numerical finite-difference model for plane viscous Newtonian flow of an incompressible continuous medium in a multiple-angle region with a movable inlet die wall, based on the formulation and numerical solution of the boundary value problem for the Navier-Stokes equations in curl transfer form, is derived. A numerical estimation of the influence of the direction of movement of a movable entrance die wall on computational flow lines, stream and curl functions, and viscous flow velocity fields was carried out within the scope of the developed model for a movable inlet wall of the die. The proposed hydrodynamic approach extends the ideas concerning the dynamics of the macroscopic rotation formation within the volume of the viscous physical model of a polymeric material during ECMAE or ECMAP through a die with a movable inlet wall. © 2014 Copyright Taylor & Francis Group, LLC. Source


Dremov V.V.,Donbass National Academy of Civil Engineering and Architecture | Kalashnikova O.A.,Donetsk National Technical University
Journal of Engineering Physics and Thermophysics | Year: 2013

The nonstationary problem of the solidification of a metal in molds with walls of different heat conductivities with account for the air gap between the ingot and the mold has been solved by the variational method. The temperature distribution in the liquid phase and the time dependence of the solidification front have been obtained. Numerical calculations of the motion of the solidification front in a cast iron and a ceramic mold at certain instants of time have been made. © 2013 Springer Science+Business Media New York. Source


Gerasimchuk V.S.,Kharkiv Polytechnic Institute | Shitov A.A.,Donbass National Academy of Civil Engineering and Architecture
Functional Materials | Year: 2010

The dynamics of domain walls in external alternating magnetic and electric fields has been studied in antiferromagnetic materials with linear magnetoelectric interaction. The features of vibrational and drift motion of domain walls depending on the parameters of external fields and the material characteristics are discussed. © 2010 - STC "Institute for Singale Crystals". Source


Perig A.V.,Donbass State Engineering Academy | Golodenko N.N.,Donbass National Academy of Civil Engineering and Architecture
International Journal of Advanced Manufacturing Technology | Year: 2014

The objective of this article is the description of advantages of a slanted die geometry, used for equal channel angular extrusion (ECAE) of materials. The prime novelty statement of the present research is an experimental flow pattern, obtained with circular gridlines and a numerical solution of a viscous flow 2D problem for the slanted die, derived with Navier–Stokes equations in curl transfer form. The geometry of the slanted die was chosen for the case of a rectangular die with channel intersection angle 2θ = 90° and with parallel slants in the channel intersection zone, where the slant width is equal to the inlet and outlet channel widths. Computational material flow kinematics, macroscopic rotation patterns, material flow velocity fields, tangential stresses, and punching pressure fields during viscous materials ECAE have been derived with a numerical finite-difference solution of the curl transfer equation for 2D viscous flow of incompressible continuum during ECAE. Theoretical results have been verified with physical simulation experiments by the introduction of initial circular gridlines. Both theoretical and computational results confirm the suitability and technological advantages of dies with parallel slants over the known Segal and Iwahashi dies for ECAE, as slanted convergent dies enable the reduction of the dead zone size and provide the minimization of dangerous macroscopic rotation during ECAE processing of both metal and polymer materials. © 2014, Springer-Verlag London. Source

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