Donbass State Engineering Academy

Kramators’k, Ukraine

Donbass State Engineering Academy

Kramators’k, Ukraine

Time filter

Source Type

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.


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.


Zhbankov I.G.,Donbass State Engineering Academy | Perig A.V.,Donbass State Engineering Academy
Materials and Manufacturing Processes | Year: 2013

Geometric parameters of the shrinkage cavities in ingots without hot tops from the NKMZ and "Izhorskie zavodi" plants varying in mass from 1.6-180 tons with different ingot height to average diameter ratio have been studied. The influence of geometric parameters, solidification conditions, and steel chemical composition on the relative depth of the ingot shrinkage cavity was studied. The possibility of forging ingots without hot tops by using a preliminary upsetting by plates with holes using different configurations was studied. Theoretical research based on a FEM of ingot upsetting in flat, convex, and concave plates with holes has been conducted. Dimensions of instruments which allow the measurement of maximum local deformations in the ingot shrinkage cavity area during the upsetting process have been determined. Dependence of the relative deformation of upsetting ingots without hot tops upon geometric parameters of the instrument and the ingot parameters was determined. © 2013 Copyright Taylor and Francis Group, LLC.


This article deals with a phenomenological description of experimentally determined complex geometric shape of material dead zone during Equal Channel Angular Extrusion (ECAE) through a Segal 2θ-die with a channel intersection angle of 2θ>0° and 2θ<180°. Taking into account the complex dead zone geometry in a 2θ-die, a two-parameter Rigid Block Method (RBM) approach to a two-parameter Upper Bound Method (UBM) has been introduced with Discontinuous Velocity Field (DVF) for planar flow of plastic incompressible continua. The two-parameter UBM has allowed us to derive the numerical estimations for such energy-power parameters of ECAE as punching pressure and accumulated plastic strain for 2θ-dies. The obtained computational data have been compared with the one-parameter analytic UBM solution. Good agreement between the two computational results has been found. © 2015.


Perig A.V.,Donbass State Engineering Academy
Materials Research | Year: 2014

Equal Channel Angular Extrusion (ECAE), sometimes referred to as Equal Channel Angular Pressing (ECAP), is a Severe Plastic Deformation technique. However the energy-power parameters of ECAE have not been fully addressed in previous known publications. The present article is focused on the punching pressure, accumulated plastic strain, and dead metal zone geometry estimation during ECAE of metal workpieces through a 2θ-die with a channel intersection angle of 2θ>0° and 2θ≠90°. Computational analytical results for ECAE technological parameters have been analytically derived for planar flow of a plastic, incompressible, non-hardening metal workpiece in an angular Segal die with 2θ>0° and 2θ≠90°. This is accomplished through the use of an Upper Bound Method (UBM) with Discontinuous Velocity Field (DVF) introduction. The development of the Dead Zone (DZ) for metal ECAE through a 2θ-die with 2θ>0° and 2θ≠90° has been analytically investigated. The obtained computational results for 2θ-die have been compared with the slip line analytic solutions of Segal for non-rectangular 2θ-dies of the same geometry. Good agreement between the two computational results has been found. The physical modeling techniques using plasticine have confirmed the appearance of a dead zone and material flow dynamics during ECAE through the Segal 2θ-die. © 2014.


Perig A.V.,Donbass State Engineering Academy | Laptev A.M.,Donbass State Engineering Academy
Journal of the Brazilian Society of Mechanical Sciences and Engineering | Year: 2014

The mechanics of equal channel angular extrusion (ECAE) in a rectangular die was studied by upper bound method and rigid block model of deformation with two variables (two degrees of freedom). The appearance of a dead zone in the die external corner was assumed and verified by physical simulation using plasticine as a modeling material. The obtained dependences of ECAE pressure, total ECAE shear and geometrical parameters of dead zone upon friction factor were compared with corresponding results of upper bound rigid block analysis with one variable (one degree of freedom) and with the results of slip line analysis published by the authors elsewhere. It was demonstrated that an increase in degrees of freedom in an ECAE rigid block model from one to two results in much better approximation of the reference data of slip line analysis. The authors believe that an increase in the numbers of degrees of freedom and flexibility of a rigid block model generally leads to a better accuracy in modeling of other metal forming processes as well. As an example, the ECAE pressure of the aluminum 6061 alloy was calculated and compared with the experimental data from literature. A good agreement between them was found. The importance of consideration of friction in the inlet and outlet die channels was emphasized. © The Brazilian Society of Mechanical Sciences and Engineering 2013.


Zhbankov I.G.,Donbass State Engineering Academy | Perig A.V.,Donbass State Engineering Academy
Materials and Manufacturing Processes | Year: 2013

Classification of forging schemes which involve intensive shear deformation in the billet have been proposed. An investigation of the stress-strain state in the billet during forging by anvils with slant has been done. The influence of such parameters as relative billet feed, anvil stroke, and anvil slant angle on billet strain state during the forging process has been determined. Recommendations of forging regimes in the form of such parameters as billet feed, anvil stroke, anvil slant angle, and billet rotation sequence have been made. The feasibility of forging a 41Cr4 steel billet with slanted anvils as a round shaft was confirmed experimentally, and the advantages of this new scheme over traditional flat anvil forging have been identified. © 2013 Taylor & Francis Group, LLC.


Perig A.V.,Donbass State Engineering Academy | Zhbankov I.G.,Donbass State Engineering Academy | Matveyev I.A.,Donbass State Engineering Academy | Palamarchuk V.A.,Donbass State Engineering Academy
Materials and Manufacturing Processes | Year: 2013

The principal objective of the present article is to take into account the effect of deformation zone geometry on the deformation unevenness of material plastic flow in the Equal Channel Angular Extrusion (ECAE) of metals through the use of 2D Finite-Element Simulation. This approach allows us to analyze plastic material flow through the proposed generalized Iwahashi angular die with a variable external wall at the channel intersection zone. A varied set of quadratic curves has been used to define the possible external wall of the contact surface zone. The proposed approach allows us to extend ideas concerning the influence of the angular die deformation zone external wall on the energy-power parameters of the equal channel material flow. The results indicate that the preferred choice is to introduce the external die wall in the form of a hyperbola, which allows the achievement of high strain intensity 0.692. 0.792, low strain unevenness 0.167. 0.310, and low material waste 0.016. 0.047 during one pass of the processed metal through the generalized angular die with a channel intersection angle of 90°. © 2013 Copyright Taylor and Francis Group, LLC.


Perig A.V.,Donbass State Engineering Academy | Zhbankov I.G.,Donbass State Engineering Academy | Palamarchuk V.A.,Donbass State Engineering Academy
Materials and Manufacturing Processes | Year: 2013

The principal objective of the present article is focused on the determination of the effect of angular die radii on the strain intensity, strain unevenness, and material waste for material plastic flow in the Equal Channel Angular Extrusion (ECAE) of metals through the use of a 2D Finite-Element Simulation and a regression analysis technique. This analysis is used to determine the effect of external and internal radii of an angular die and workpiece length on the value of the workpiece truncated "fore part," which characterizes the workpiece waste. It has been found that the relative radius of the external rounding of the angular die has to be minimized at 0.028, and the internal relative radius of the angular die must be within a range of [0-0.3]. The proposed angular die radii conditions for workpieces with relative length 8.474 have allowed the achievement of high strain intensity [0.79-0.91] together with low strain unevenness [0.35-0.48] and minimal waste of an initial nonstationary workpiece part [0.051-0.055] during one pass of an ECAE. Derived regression models give the background for experimentally determined appropriateness for deformation of longer workpieces during angular extrusion with the objective of reducing deformed material waste. © 2013 Copyright Taylor and Francis Group, LLC.


Abramov A.,Donbass State Engineering Academy
Modern Physics Letters B | Year: 2011

A method of calculation of donor impurity states in a quantum well is developed. The used techniques have made it possible to find the binding energy both of ground and excited impurity states attached to each QW subband. The positions of the resonant states in 2D continuum are determined as poles of corresponding wave functions. As a result of such an approach the identification of resonant states in 2D continuum is avoided, introducing special criterions. The calculated dependences of binding energies versus impurity position are presented for various widths of Si/Si1-xGex quantum wells. © 2011 World Scientific Publishing Company.

Loading Donbass State Engineering Academy collaborators
Loading Donbass State Engineering Academy collaborators