National Metallurgical Academy of Ukraine
Dnipropetrovsk, Ukraine
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Akhundo V.M.,National Metallurgical Academy of Ukraine
Mechanics of Composite Materials | Year: 2016

A two-level carcass theory as applied to media with a polycrystalline structure at large elastic and plastic deformation of crystals (crystal grains) is presented. The theory is incremental, in accordance with the incremental nature of governing equations of a crystal, which take into account the prehistory of its deformation in the medium. The theory is based on the field of carcass (macroscopic) displacements, which determines the material displacements of carcass points and carcass (macroscopic) deformations of the medium. At the macromechanical level, the equations of macroscopic deformation and motion are given in an incremental form. At the micromechanical (locally structural) level, incremental microboundary-value problems for nodal presentation blocks of the polycrystalline material are solved on the basis of carcass displacements and their increments. From the internal fields of nodal blocks and their increments found, the incremental macroscopic stresses are determined, which allow one to close the system of equations of the macromechanical level of analysis. © 2016 Springer Science+Business Media New York.

Akhundov V.M.,National Metallurgical Academy of Ukraine
Mechanics of Composite Materials | Year: 2017

Form changes of a cross-reinforced toroidal body under butt-end torsion and rotation are investigated on the basis of carcass theory of fibrous media at large deformations, including macro- and micromechanical levels of analysis. The form changes are considered as the result of external loadings specified by the field of carcass displacements. This field, which is an integral manifestation of internal fields of the body during its deformation, is determined on the macrolevel. The internal fields are found by solving boundary-value problems on the micromechanical level for the nodal blocks of material on the basis of the model of a piecewise homogeneous medium. Configurations of the body at the values of torsion angle and rotational speed close to limiting ones are presented. The configurations of material blocks in the deformed body, which reflect its internal fields, are illustrated. The regions of folding in the binder close to butt-end sections, where the body is connected with nondeformable shafts, are revealed. © 2017 Springer Science+Business Media New York

Rakhmanov S.R.,National Metallurgical Academy of Ukraine
Steel in Translation | Year: 2016

Mathieu–Hill equations are used to describe the parametric vibration of the connecting rod in the primary drive of a cold-rolling mill for pipe production. The Eins–Strett diagram is presented, and regions of stable connecting-rod operation are identified. Connecting-rod designs are proposed (on the basis of highstrength alloys), and the crank of the primary drive is modernized (with splitting of the crank gears). That stabilizes pipe production. © 2016, Allerton Press, Inc.

Malyi E.I.,National Metallurgical Academy of Ukraine
Coke and Chemistry | Year: 2014

If coal is modified by the volatile products formed in pyrolysis, high-quality blast-furnace coke may be produced from batch with a smaller proportion of expensive clinkering coal. In such coking, the batch is modified in the coking chamber; its clinkering properties are improved as a result of partial hydrogenation. New parameters are proposed to describe the modification of the batch; the variation in clinkering properties is established as a function of these parameters. The quality of the coke obtained from modified coal batch is assessed. The relationship between coke quality and the batch composition is determined. The formulas obtained may be used to predict coke quality. Tests show that partial hydrogenation improves coke quality © 2014, Allerton Press, Inc.

Dobrov I.V.,National Metallurgical Academy of Ukraine
Procedia Engineering | Year: 2016

The effect of the way of applying inclined external force pressing the bodies of translational friction pair with flat contact surface is analyzed based on theoretical and experimental research of the external friction processes. The relationship between the inclined external force and the contact stress considering external zone of the friction pair is analyzed. The conditions when it is necessary to consider the influence of external zone of friction pair, are determined. The reduced coefficient of friction based on the relationship between coefficient of sliding friction and the function of additional resistance to the relative displacement of the bodies of the friction pair is researched. It is shown that this resistance is caused by the external zone. © 2016 The Authors.

Akhundov V.M.,National Metallurgical Academy of Ukraine
Mechanics of Composite Materials | Year: 2014

The results of research into regularly fiber-reinforced bodies under large deformations, obtained by using a single-level applied and two-level carcass theories, are presented. Uni-, two-, and three-directionally reinforced bodies of revolution and prismatic ones, with high and low content of reinforcing fibers, subjected to butt-end torsion under the action of compression and rotation-caused centrifugal forces are investigated. Problems on the butt-end torsion of a thick-wall cylinder with axially arranged fibers and of a thick-wall toroidal shell with meridionally located fibers are considered. © 2014 Springer Science+Business Media New York.

Svyetlichnyy D.S.,AGH University of Science and Technology | Mikhalyov A.I.,National Metallurgical Academy of Ukraine
ISIJ International | Year: 2014

The paper presents three-dimensional frontal cellular automata (FCA) based model for modeling of microstructure evolution during technological processes. It is hierarchical system. The first level is FCA, the second level is modules of microstuctural phenomena; and the third level is models of technological processes. The phase transformation module (PTM) is one of the components of the second level. PTM will contain several models of phase transformation; one of them presents transformation of austenite into ferrite and perlite. This phase transformation controlled by diffusion is considered as the nucleation and the growth of grains of other phases. The nucleation algorithm is presented in the paper. An effect of nucleation sites on final microstructure was studied on three extreme nucleation variants: nucleation on the boundaries, on the edges and in the grain corners. Simulations have been carried out for low cooling rate and relatively long time of the holding at appropriate temperature. The simulation results of the microstructure evolution studies are presented in the paper. © 2014 ISIJ.

Mashinistov V.Y.,National Metallurgical Academy of Ukraine | Galkin O.F.,National Metallurgical Academy of Ukraine
Metallurgical and Mining Industry | Year: 2015

The technology for utilization of metal contaminated with radioactivity at the enterprises of metallurgy was considered. The presented technology makes use of the influence of the heat (smelting) process on the level of ionizing radiation off the metal surface. Taking into account the effect of the radioactive self-decontamination and evaporation of radionuclides while metal melting allows return the metal contaminated with radioactivity into economic turn-over. This metal can be used without any restrictions. © Metallurgical and Mining Industry, 2015.

Dobrov I.V.,National Metallurgical Academy of Ukraine
Procedia Engineering | Year: 2015

The characteristic of the inertia forces within the classification of forces during solving the problems of the mechanics of machines was given. This characteristic is based on the simultaneous and unconditional compliance with the laws of Newton and the law of the energy conservation. It is proved that every potential field of motion of a physical body corresponds to a potential velocity field and the poles of these fields are located in the same point in space. For an absolutely rigid body moving with a variable velocity the inertia force is the internal potential force and potential of the inertia force is the velocity of the physical body. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

Akhundov V.M.,National Metallurgical Academy of Ukraine
Mechanics of Composite Materials | Year: 2016

The basic propositions and equations of the two-level carcass theory of media with a regular structure are extended to media with locally curved fibers under large deformations of the matrix and fibers. The case of reinforcement with rectilinear and nonlocally curved fibers is also considered. The macromechanical equations of deformation determining the measures of microscopic deformations from the field of macroscopic displacements are presented. A theory of macroscopic stresses at large deformations of constituents of a fibrous material is given, which can also be based on material blocks of a medium with locally curved sides. The equations of macroscopic motion of media obtained by using the concepts of macroscopic displacements and stresses are presented. The statement of boundary-value problems solved on the micromechanical level for the nodal blocks of a material medium is considered. © 2016 Springer Science+Business Media New York

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