## Modelling of combined thermomechanical processing of stainless steel wire

Mathematical Modeling, Vol. 8 (2024), Issue 1, pg(s) 10-13

In this article, a number of theoretical studies have been conducted on a new combined process of multicycle thermomechanical processing, including wire drawing and subsequent cooling in liquid nitrogen. When analyzing the deformation, it was found that the presence of intermediate heating to ambient temperature allows calculating the force according to the Krasilshchikov formula and the wellknown nomogram of the tensile strength of AISI-316 steel at 20°C with minimal errors. The lack of heating leads to the fact that the second and third drawing cycles take place at partially negative temperatures in the workpiece section. This leads to an increase in the difference in the force values obtained by calculation and during modeling. To be able to use the Krasilshchikov formula and the nomogram of the tensile strength of AISI-316 steel at 20°C, it is necessary to adjust the resulting force values by increasing by about 30% for a diameter of 6 mm and 20% for a diameter of 9 mm in the absence of heating of the workpiece and by 35% for a diameter of 6 mm and 25% for a diameter of 9 mm in in case of preheating the workpiece.

## Study of the defect closure behaviour during forging in a step-wedge strikers

Machines. Technologies. Materials., Vol. 16 (2022), Issue 4, pg(s) 127-129

This work is devoted to the study of the internal defect closure during metal broaching in step-wedge strikers with wedge and depression by FEM in Deform program. A through cylindrical hole with a diameter of 3 mm was considered as an internal defect. At the same time, three variants of the defect vertical location were modeled – in the workpiece center, near the upper face of the wedge and near the lower face of the depression. In all three cases, the internal defect closure is uneven. The most intense defect closure is observed when it is located in the workpiece axial zone. Defects located near the strikers surface zones are not closed well enough. The stress-strain state analysis showed that the defect location affects the distribution nature of stresses and strains along the workpiece section.

## Development and computer modeling of a new forging technology in step-wedge strikers

Machines. Technologies. Materials., Vol. 15 (2021), Issue 6, pg(s) 226-229

A computer simulation of the broaching of the workpiece in step-wedge-shaped strikers of the first and second configurations was carried out by the finite element method. The comparison was made according to the following parameters of the stress-strain state: equivalent strain, average hydrostatic pressure, damage criterion, as well as the deformation force. A comparative analysis of the stress – strain state showed that the second configuration of step-wedge-shaped strikers is the most optimal option for implementing the process of broaching rectangular or square blanks. When using them, a more uniform distribution of the stress state is realized, the deformation processing is sufficiently realized in comparison with the broaching in step-wedge-shaped strikers of the first configuration

## STUDY OF STRESS-STRAIN STATE AND TEMPERATURE FIELD DURING ROLLING UNDER THE NEW SCHEME WITH ALTERNATING AND SHEAR DEFORMATIONS

Mathematical Modeling, Vol. 3 (2019), Issue 2, pg(s) 55-58

In this paper, a computer simulation of a new technology of thick-sheet rolling, including rolling in rolls with a relief surface followed by rolling on rolls with a smooth barrel to the desired size. The analysis of effective plastic deformation, hydrostatic pressure and temperature field was carried out according to the results of modeling. According to the results of the analysis of effective strain, maximum of processing in the first pass receives the ridge area, but after the second pass observed alignment distribution of this parameter over the cross section. The study of the temperature field showed that the greatest temperature difference in the cross section occurs when rolling in relief rolls, in the future when rolling in smooth rolls due to the increase in the contact surface area, this difference decreases. Analysis of hydrostatic pressure showed the presence of both compressive and tensile stresses in the deformation zone. Such distribution is caused by the presence of a relief surface after 1 pass in the further alignment of the strip profile, which occurs both in the longitudinal and transverse directions.

• ## Computer modelling of radial-shear rolling of austenitic stainless steel AISI-321

Machines. Technologies. Materials., Vol. 12 (2018), Issue 12, pg(s) 497-500

In this paper the results of modelling of radial-shear rolling process of austenitic stainless steel AISI-321 are presented. The simulation in Simufact Forming program complex was performed. The conditions of simulation for radial-shear mill SVP-08 of Rudny industrial Institute were adopted. The various parameters of stress-strain state (effective plastic strain, effective stress, mean normal stress and Lode-Nadai coefficient) and also microstructure evolution with rolling force were considered. It is revealed that radial-shear rolling is an effective process for obtaining of high quality round billets from stainless steels of austenitic class.

• ## Peculiarities of stress-strain state of toroidal pressure hull, made by spiral winding

Machines. Technologies. Materials., Vol. 12 (2018), Issue 11, pg(s) 462-645

Peculiarities of stress-strain state of pressure hull of underwater technical device, shaped as torus with circle intersection, which was obtained by spiral winding of polymer composite materials, are presented.

• ## CALCULATION OF PARAMETERS OF TENSELY DEFORMED STATE OF DISK PIEZOELEMENTS WITH SURFACES PARTIALLY COVERED BY ELECTRODES

Machines. Technologies. Materials., Vol. 12 (2018), Issue 9, pg(s) 362-366

A mathematical formulation of the boundary problems of mathematical physics is made, sequential solution which allows describing the stress-strain state and the transfer characteristics of the piezoelectric elements with surfaces partial covering by electrodes. The set of formulated boundary problems makes mathematical content of energy-power method of analysis of the physical condition of the piezoelectric elements in the regime of forced oscillations under the influence of an external source of electrical energy. The proposed sequence of computational procedures can be used in the study of forced oscillations of microelectromechanical structures.

• ## PECULIARITIES OF STRESS-STRAIN STATE OF TOROIDAL PRESSURE HULL, MADE BY WINDING

Machines. Technologies. Materials., Vol. 12 (2018), Issue 6, pg(s) 240-243

The peculiarities of evaluation of stress-strain state of the pressure hull of the underwater technical device, shaped as torus with circle intersection, which was obtained by transverse winding combined with longitudinal winding (or facing) of polymer materials, while taking variable thickness by meridian section into an account, are presented.

## THE INFLUENCE OF THE TOOTH PROFILE SHAPE ON THE STRESS-STRAIN STATE IN THE GEAR

Machines. Technologies. Materials., Vol. 12 (2018), Issue 4, pg(s) 153-156

The shape of the tooth profile affects the stress-strain state in the gear. In the case of a fatigue failure the stress state is a decisive criterion for the lifetime of the gear. The shape of the tooth flank affects the magnitude of the contact pressure in the contact of the meshing teeth. The consequence of which are surface cracks and pitting. The shape of the tooth root influences the magnitude of the root stress, which, when limit is exceeded, leads to root cracks and teeth breakage. Many different types of gearing are known, but in the practice most widely used is the involute one. Other types of gearing become interesting especially when polymer materials are being used. If the gears are injection molded the type of gearing does not affect the cost of the tool. In the case of metal gears, standardized tools for involute gearing make the use of other special types of gearing economically unjustified. Our research is focused on the S-gears, which got their name from the S-shaped path of contact. The paper presents the research of how the defining parameters of S-gears impact the stress-strain state in the gear. This was done using a numerical model which simulates gear meshing. The stress state of two different types of S-gears was compared with the stress state in an involute gear of the same dimensions (same module, number of teeth and width). It was found that with a proper choice of gearing type we can improve the load bearing capability of the gear pair. With use of our numerical model we have also analyzed the impact of the tip relief on the stress state. The numerical model was validated for the case of meshing steel involute gears, where we can compare the results of the model with the results according the ISO 6336 calculation. A good match between the results of the model and results according the standard was obtained. After validation the same numerical model was used for the calculation of the stress-strain state in S-gears. This was calculated then for metal and polymer (POM/PA) gear pairs.

• ## STUDY OF THE STRESS-STRAIN STATE OF THE VIBRATING EQUIPMENT

In this paper is studied a vibratory conveyor that is placed on an elastic base. Using the closed contours method it was determined the system that needs to be solved to obtain graphical representation for the generalized coordinates determining the position of the mechanical system elements. The shaking conveyor represents the chase hanged or supported to the fixed section. The chase commits oscillating motions hereupon the cargo which is in the chase, migrates concerning to the chase. The nature of the flow and its parameters are determined by the nature of the oscillating committed by the chase. Justifying the dynamic parameters of the shaking conveyor and a study of the stress-strain state. Installation causes fluctuations fixed tray. Uniformly distributed load on the tray acts in each element of the mechanism. On the basis of the program APM structure 3D investigated the stress-strain state and determined movement of each link mechanism with results and calculations.

• ## MODELING AND STUDY OF THE PROCESS OF BILLETS EXTRUSION WITH ADDITIONAL BACK- PRESSURE IN EQUAL CHANNEL STEP MATRIX

This work is devoted to the study of stress-strain state and power parameters in the simulation of the process of extrusion billets with additional back-pressure in equal channel step matrix. Analyzing the obtained results we can conclude that the matrix without backpressure cannot achieve complete closing of internal defects of a deformable metal. The backpressure created by the increase of the roughness of the output channel of the matrix, has a beneficial effect on the stress-strain state of the metal, which in turn allows you to provide the best structured deformable metal