scholarly journals Numerical Mathematical Simulation of Penetration of Indenters of Different Shapes During Strengthening Machine Parts via Local Loading of Deformation Zone

2018 ◽  
Author(s):  
O.V. Pilipenko ◽  
S.Y. Radchenko ◽  
V.A. Golenkov ◽  
D.O. Dorohov
Keyword(s):  
Mathematical Simulation ◽  
Deformation Zone ◽  
Local Loading ◽  
Different Shapes ◽  
Machine Parts

scholarly journals Energy-efficient omd processes with complex local loading for the production of machine parts with a given level of properties

2022 ◽  
Vol 1211 (1) ◽  
pp. 012016
Author(s):  
V A Golenkov ◽  
D O Dorohov ◽  
S Y Radchenko
Keyword(s):  
Metal Forming ◽  
Energy Efficient ◽  
Deformation Zone ◽  
Strain State ◽  
Point Of View ◽  
Theoretical Point ◽  
Local Loading ◽  
New Energy ◽  
Machine Parts ◽  
Shape And Size

Abstract The article discusses some new energy-efficient metal forming processes (PMD) with complex local loading of the deformation zone for the production of machine parts with a given level of properties. The place of such processes in the aggregate of all OMD technologies is shown, and their classification is given. The initial data of numerical mathematical modeling of the specified class of processes for a particular case are given, the features of the stress-strain state of the metal in the deformation zone are revealed. In the study, from a theoretical point of view, one of the important practical aspects of these technologies is considered: the effect of the value of axial compression on the shape and size of the deformation zone arising from the action of local loading of the workpiece.

Mathematical simulation of seamless pipes extrusion and rational calibration of die

2021 ◽  
Vol 77 (1) ◽  
pp. 70-79
Author(s):  
S. R. Rakhmanov
Keyword(s):  
Mathematical Simulation ◽  
Deformation Zone ◽  
Metal Flow ◽  
Flow Speed ◽  
Zone Length ◽  
Technology Application ◽  
Extrusion Press ◽  
Length Increase ◽  
Die Profile ◽  
Zone Parameters

Technology of seamless pipes production by extrusion enables to deform pipe workpieces made of low-plastic materials. However, low durability of the working instrument restricts the area of the technology application. The purpose of the work was to specify optimal parameters of technological processes of pipes extrusion. Minimization of energy and force parameters of the deformation zone and an increase of once-only metal deformation were accepted as criteria. They will enable to increase the presses productivity, increase durability of working instrument and accuracy of pipes geometric dimensions. A mathematical model of deformation zone and stressed state of pipe workpiece were elaborated. Influence of the die generatrix calibration and deformation zone parameters on the character of energy and force parameters change revealed. Dependence of energy and force parameters on the die calibration and geometric parameters of deformation zone for the press 50 MH was established. The results of mathematical simulation of pipes extrusion showed that along the whole deformation zone length, increase of metal flow speed results in an increase of tangential and normal stresses on the forming mandrel and calibrated die. The task of parametric optimization of die profile (calibration) was accomplished in interpretation of base variation Euler’s task for a determined functional of pipes extrusion. It was established that while the extrusion speed is increasing, the energy and force parameters of the deformation zone are getting pronounced dynamic character. At that, by optimization of die calibration, an increase of the extrusion press 50MH working instruments durability was reached, as follows: dies – by two times, mandrels – by 4 times, container bushes – by 40% and press-washers – by 2 times.

scholarly journals Determination of the stress state in the deformation zone under local loading

2019 ◽  
Vol 315 ◽  
pp. 052080
Author(s):  
Yury Melnik ◽  
Semen Zaides ◽  
Nikolaj Bobrovskij ◽  
Ngo Cao Cuong ◽  
Olesja Levitskih ◽  
...  
Keyword(s):  
Stress State ◽  
Deformation Zone ◽  
Local Loading

scholarly journals Numerical Optimization of Stress Concentration in Composite Structures for Different Material Arrangement

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2957
Author(s):  
Sushant Bhalchandra Pate ◽  
Ryszard Korycki
Keyword(s):  
Composite Structures ◽  
Glass Fibers ◽  
Weighted Average ◽  
Composite Plates ◽  
Sandwich Composite ◽  
Stress Distributions ◽  
Complex Load ◽  
Material Characteristics ◽  
Different Shapes ◽  
Machine Parts

Complex machine parts are characterized by different shapes, material characteristics and working loads. The simultaneous theoretical optimization of shape and material properties is difficult because the single objective functional with a unique physical interpretation is unknown for these two features. The optimization is the multi-criteria procedure or the functional is a weighted average of partial criteria with the assumed weight values. Therefore, the structure and material characteristics are optimized numerically. The main goal of the article was to model and optimize the stress distribution inside the composite plates subjected to complex load. The advanced material composition was made of four different materials: steel, ductile iron, E-glass fibers and carbon fibers. The stress distributions were optimized for the homogeneous plate, the sandwich composite made of metal and textile layers, and the plate with additional stiffening elements (ribs and another plate along the neck portion). Based on the numerical simulations, the optimal structural shapes and material arrangements were determined.

CONTROLLED FORMATION OF THE DESIGNED MECHANICAL PROPERTIES OF MACHINE PARTS BY DEFORMATION HARDENING IN THE CONDITIONS OF COMPLEX LOCAL LOADING OF THE DEFORMATION ZONE

2020 ◽  
Vol 2 ◽  
pp. 34-42
Author(s):  
S.Yu. RADCHENKO ◽  
V.A. GOLENKOV ◽  
D.O. DOROKHOV
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Deformation Zone ◽  
Cast Alloy ◽  
Processing Parameters ◽  
Local Loading ◽  
Technological Parameters ◽  
Microhardness Distribution ◽  
Deformation Hardening ◽  
The Cross

The process of complex local loading of the deformation zone is considered using the example of processing a sleeve made of a bronze alloy, the mechanical properties of the cast alloy under study were determined, and the parameters of the microhardness distribution over the cross section of the processed workpiece were investigated. Plots of the distribution of various microhardness parameters over the cross section are plotted depending on the number of processing cycles. A mathematical model of the process under consideration and its comparison with experimental data is shown. The description of the technique in the form of an algorithm of actions for the appointment of technological parameters. An example is presented in the form of a finished nomogram for the assignment of specific processing parameters to obtain a given hardening depth and value.

Structural phenomena in the growth of carbon nanotubes

1993 ◽  
Vol 51 ◽  
pp. 750-751
Author(s):  
Jun Jiao
Keyword(s):  
Carbon Nanotubes ◽  
Growth Mechanism ◽  
Carbonaceous Material ◽  
Cluster Growth ◽  
Structural Elements ◽  
Rich Variety ◽  
Different Shapes ◽  
Point To Point

HREM studies of the carbonaceous material deposited on the cathode of a Huffman-Krätschmer arc reactor have shown a rich variety of multiple-walled nano-clusters of different shapes and forms. The preparation of the samples, as well as the variety of cluster shapes, including triangular, rhombohedral and pentagonal projections, are described elsewhere.The close registry imposed on the nanotubes, focuses attention on the cluster growth mechanism. The strict parallelism in the graphitic separation of the tube walls is maintained through changes of form and size, often leading to 180° turns, and accommodating neighboring clusters and defects. Iijima et. al. have proposed a growth scheme in terms of pentagonal and heptagonal defects and their combinations in a hexagonal graphitic matrix, the first bending the surface inward, and the second outward. We report here HREM observations that support Iijima’s suggestions, and add some new features that refine the interpretation of the growth mechanism. The structural elements of our observations are briefly summarized in the following four micrographs, taken in a Hitachi H-8100 TEM operating at an accelerating voltage of 200 kV and with a point-to-point resolution of 0.20 nm.

Simulation of vibration piercing of pipe blank at press

2020 ◽  
Vol 76 (11) ◽  
pp. 1128-1138
Author(s):  
S. R. Rakhmanov
Keyword(s):  
High Frequency ◽  
Deformation Zone ◽  
Pipe Blank ◽  
Equipment Operation ◽  
Metal Deformation ◽  
Technological Tool ◽  
High Frequency Vibrations ◽  
Pipe Blanks ◽  
Wave Phenomena

In some cases, the processes of piercing or expanding pipe blanks involve the use of high-frequency active vibrations. However, due to insufficient knowledge, these processes are not widely used in the practice of seamless pipes production. In particular, the problems of increasing the efficiency of the processes of piercing or expanding a pipe blank at a piercing press using high-frequency vibrations are being solved without proper research and, as a rule, by experiments. The elaboration of modern technological processes for the production of seamless pipes using high-frequency vibrations is directly related to the choice of rational modes of metal deformation and the prediction resistance indicators of technological tools and the reliability of equipment operation. The creation of a mathematical model of the process of vibrating piercing (expansion) of an axisymmetric pipe blank at a piercing press of a pipe press facility is an actual task. A calculation scheme for the process of piercing a pipe plank has been elaborated. A dependence was obtained characterizing the speed of front of plastic deformation propagation on the speed of penetration of a vibrated axisymmetric mandrel into the pipe workpiece being pierced. The dynamic characteristics of the occurrence of wave phenomena in the metal being pierced under the influence of a vibrated tool have been determined, which significantly complements the previously known ideas about the stress-strain state of the metal in the deformation zone. The deformation fields in the zones of the disturbed region of the deformation zone were established, taking into account the high-frequency vibrations of the technological tool. It has been established that the choice of rational parameters (amplitude-frequency characteristics) of the vibration piercing process of a pipe blank results in significant increase in the efficiency of the process, the durability of the technological tool and the quality of the pierced blanks.

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