Shot Blasting Process Schematization for Rollers Using Slip-Line Method

2020 ◽  
Vol 989 ◽  
pp. 647-653
Author(s):  
Nikolay N. Ogarkov ◽  
Elena Yu. Zvyagina ◽  
Lyudmila I. Antropova
Keyword(s):  
Plastic Deformation ◽  
Theoretical Analysis ◽  
Slip Line ◽  
Roughness Parameters ◽  
Shot Blasting ◽  
Working Surface ◽  
Elastic And Plastic Deformation ◽  
The Impact ◽  
Pass Mill ◽  
Theoretical Results

The considered theoretical analysis of the roughness parameters formation of the rolling face of the pinch pass mills, when they are indented with shot, allows to obtain more adequate and convenient theoretical results for use in practice. The formation of a rough layer on the rolling working surface of the pinch pass mill is determined by the impact and penetration of the shots into its surface. When this occurs, the elastic and plastic deformation of the roll materials and shot with the dimple formation and the displacement of a portion of the deformed roll material on the edges of this dimple takes place. The obtained results allow using the mathematical dependencies to control purposefully the process of shot blasting and correct it when texturing the working rolling faces of the pinch pass mills.

scholarly journals The mechanism of nanostructuring the surface of engineering parts during shot blasting

2020 ◽  
Vol 16 (2) ◽  
pp. 146-151
Author(s):  
German L. Kolmogorov ◽  
Alexandr S. Vysotin
Keyword(s):  
Plastic Deformation ◽  
Surface Layer ◽  
Contact Problem ◽  
High Speed ◽  
Theory Of Elasticity ◽  
Atomic Diffusion ◽  
Plastic State ◽  
Cold Plastic Deformation ◽  
Shot Blasting ◽  
The Impact

Relevance. The paper considers shot blasting, which is a widely used method for improving the surface properties of parts (such as fatigue strength, hardness, and elongation) due to cold plastic deformation, which results in nanostructuring of the surface of the processed material, accompanied by a reduction in the grain size of its crystal structure. The conditions for the formation of a nanostructured surface layer when processing parts with a shot stream are studied. The aim of the work is to determine the conditions of nanostructuring during shot blasting due to plastic deformation, determined by the impact of the shot, which collides with the treated surface at high speed. Methods. To solve the stated problems, we used the solution of the contact problem of the theory of elasticity on the action of a concentrated force on the elastic half-space, the role of which is played by the workpiece. The conditions of the onset of plastic deformation in the surface layers of the workpiece are determined. Cold plastic deformation provides nanostructuring of the surface layer of the workpiece, increasing strength, fatigue life, atomic diffusion and improving tribotechnical characteristics. Results. Based on the contact problem of the theory of elasticity, the problem of the formation of a nanostructured layer on the surface of the workpiece during shot blasting has been solved. An analytical dependence has been obtained, which allows predicting the transition of the material to a plastic state and nanostructuring the surface of the workpiece during shot blasting.

scholarly journals Stress state and power parameters during pulling workpieces through a special die with an inclined working surface

2021 ◽  
pp. 161-176
Author(s):  
Zhassulan Ashkeyev ◽  
Maksat Abishkenov ◽  
Serik Mashekov ◽  
Anna Kawałek
Keyword(s):  
Plastic Deformation ◽  
Stress State ◽  
Slip Line ◽  
Deformation Zone ◽  
Geometric Parameters ◽  
Contact Friction ◽  
Plastic Deformation Zone ◽  
Rigid Plastic ◽  
Shear Deformations ◽  
Working Surface

The study of the stress state and power parameters when pulling workpieces in a special die with an inclined working surface at various shapes of the plastic deformation zone and geometric parameters of the special die was conducted. The distinctive feature of the proposed special die and the metal treatment process in the working channel of this die was described. The theoretical provisions and assumptions from the fundamental theory of plasticity and metal forming were used. The influence of the intensity of shear deformations on the stress state and force at the angles of inclination of the working surface of the die within 45–20°, the value of the ratio of the diameter of the workpiece to the length of the inclined surface d/z=1.5–2.0 was investigated. The optimal d/z ratio was determined by the method to a rigid punch indenting a rigid-plastic half-space, as well as by the method of strain energy. The field of slip lines and hodographs of velocities for various shapes of the deformation zone and geometric parameters of a special die were constructed. Based on the constructed slip line fields and velocity hodographs, the mean stress and stress components at the nodal points of the slip line field with the compilation of the equilibrium equations for all forces applied to the plastic zone were calculated. The study of the influence of contact friction between the working surface of the die channel and the workpiece on the stress state and power parameters during pulling was carried out. It was revealed that the optimal ratio d/z=1.5 and the optimal angle of inclination of the working channel of the die α=20°. It was found that for these parameters in the zone of plastic deformation, mainly significant compressive stresses act, which favorably affect the obtaining of a homogeneous and refined microstructure, and also exclude the appearance of anisotropy due to the implementation of maximum shear deformations in the workpiece.

Theoretical Analysis of Multiple Impact of Three Balls System

2013 ◽  
Vol 378 ◽  
pp. 46-50
Author(s):  
Yong Li Fan ◽  
Jin Li Qiao ◽  
Kun Liu ◽  
Yan Yan Li ◽  
Dan Dan Kong ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Momentum Transfer ◽  
Theoretical Method ◽  
Elastic Impact ◽  
Impact Time ◽  
Multiple Impact ◽  
The Impact ◽  
Theoretical Results

An effective theoretical method is developed to analyze three-ball system at contact in a bidimensional case basing on the impact law. The accurate solutions of the post-velocity have been computed in the paper. With the increase of between BallII and Ball III, the post-velocity of Ball III will be less and less. In fact, in the case of , the three-ball system in the same plane is consistent with the three-ball system in co-linear, when , the impact is happened only between BallI and Ball II. It is proved that the vibrating frequency influences only the impact time and the displacement of each ball for the three-ball system in the plane with elastic impact, but can not affect the momentum transfer and the post-velocities of the three balls, and all possible rigid solutions for impact are the limits of the theoretical results in some parameters of the system actually.

scholarly journals Dynamics of the rumor-spreading model with hesitation mechanism in heterogenous networks and bilingual environment

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Shuai Yang ◽  
Haijun Jiang ◽  
Cheng Hu ◽  
Juan Yu ◽  
Jiarong Li
Keyword(s):  
Lyapunov Method ◽  
Reproduction Number ◽  
Model Parameters ◽  
Rumor Spreading ◽  
Spreading Model ◽  
Reductio Ad Absurdum ◽  
The Stability ◽  
The Impact ◽  
Theoretical Results ◽  
The Basic Reproduction Number

Abstract In this paper, a novel rumor-spreading model is proposed under bilingual environment and heterogenous networks, which considers that exposures may be converted to spreaders or stiflers at a set rate. Firstly, the nonnegativity and boundedness of the solution for rumor-spreading model are proved by reductio ad absurdum. Secondly, both the basic reproduction number and the stability of the rumor-free equilibrium are systematically discussed. Whereafter, the global stability of rumor-prevailing equilibrium is explored by utilizing Lyapunov method and LaSalle’s invariance principle. Finally, the sensitivity analysis and the numerical simulation are respectively presented to analyze the impact of model parameters and illustrate the validity of theoretical results.

scholarly journals Optimising the AR Engraved Structure on Light-Guide Facets for a Wide Range of Wavelengths

Optics ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 25-42
Author(s):  
Ioseph Gurwich ◽  
Yakov Greenberg ◽  
Kobi Harush ◽  
Yarden Tzabari
Keyword(s):  
Theoretical Analysis ◽  
Light Guide ◽  
Spectral Band ◽  
Angular Range ◽  
The Past ◽  
Input And Output ◽  
Wide Range ◽  
The Given ◽  
Theoretical Results ◽  
Shape And Size

The present study is aimed at designing anti-reflective (AR) engraving on the input–output surfaces of a rectangular light-guide. We estimate AR efficiency, by the transmittance level in the angular range, determined by the light-guide. Using nano-engraving, we achieve a uniform high transmission over a wide range of wavelengths. In the past, we used smoothed conical pins or indentations on the faces of light-guide crystal as the engraved structure. Here, we widen the class of pins under consideration, following the physical model developed in the previous paper. We analyze the smoothed pyramidal pins with different base shapes. The possible effect of randomization of the pins parameters is also examined. The results obtained demonstrate optimized engraved structure with parameters depending on the required spectral range and facet format. The predicted level of transmittance is close to 99%, and its flatness (estimated by the standard deviation) in the required wavelengths range is 0.2%. The theoretical analysis and numerical calculations indicate that the obtained results demonstrate the best transmission (reflection) we can expect for a facet with the given shape and size for the required spectral band. The approach is equally useful for any other form and of the facet. We also discuss a simple way of comparing experimental and theoretical results for a light-guide with the designed input and output features. In this study, as well as in our previous work, we restrict ourselves to rectangular facets. We also consider the limitations on maximal transmission produced by the size and shape of the light-guide facets. The theoretical analysis is performed for an infinite structure and serves as an upper bound on the transmittance for smaller-size apertures.

Failure analysis of laser-textured surfaces

2000 ◽  
Vol 214 (5) ◽  
pp. 471-483 ◽  
Author(s):  
S Chilamakuri ◽  
X Zhao ◽  
B Bhushan
Keyword(s):  
Plastic Deformation ◽  
Operating Conditions ◽  
Disk Drives ◽  
Critical Number ◽  
Textured Surfaces ◽  
Tribological Behaviour ◽  
Magnetic Disk ◽  
Size And Shape ◽  
Ultrahigh Density ◽  
Theoretical Results

Friction/stiction behaviour of ultrahigh-density magnetic disk drives can be controlled by controlling the size and shape of the laser bumps. Tribological behaviour of laser-textured disk surfaces depends on the size and shape of the laser bumps, bump density and operating conditions. In this study, theoretical and experimental analyses have been carried out on nine different laser-textured disk surfaces. Stiction and friction experiments have been carried out on sombrero, V-type and W-type laser-textured disks and these results are compared with theoretical results. A good correlation is obtained between experimental and theoretical results. The effect of laser bump uniformity on critical number of bumps required to prevent plastic deformation and stiction has also been studied.

Study on the Impact of Fine-Blanking with Negative Clearance on the Materials Microstructure and Hardness

2010 ◽  
Vol 97-101 ◽  
pp. 149-152
Author(s):  
W.F. Fan ◽  
J.H. Li ◽  
Zhong Mei Zhang
Keyword(s):  
Plastic Deformation ◽  
Research Result ◽  
Original Material ◽  
Fine Blanking ◽  
Complicated Process ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
Negative Clearance ◽  
The Impact ◽  
1045 Steel

The Fine-blanking with negative clearance processing is very complicated process because the blanking clearance is negative clearance, for this reason, the state of stress and strain in sheet inside are also more complicated than conventional blanking. In the process of fine-blanking with negative, plastic deformation of the material is fiercer than conventional blanking, and the change of material inner structure and hardness is more intense because of plastic deformation. The deformation principle of fine-blanking deformation with negative clearance is analyzed by means of streamline and metallographic photograph and micro hardness. The impact of fine-blanking with negative clearance on the materials microstructure and hardness is discussed. The research result indicates that the hardening value is 1.8 times than original material itself and the maximum harden depth is 2.2mm for AISI-1045 steel in the process of blanking with negative clearance. Therefore, it could enhance fatigue strength and the working life of workpiece greatly because of the improvement of the material inner structure.

Psychological, Pedagogical and Drganizational Peculiarities of the Development of Students’ Volitional Qualities as a Factor of Success in Learning

2021 ◽  
Author(s):  
Nadiia Vientseva ◽  
◽  
Oleva Karapetrova
Keyword(s):  
Higher Education ◽  
Theoretical Analysis ◽  
Empirical Study ◽  
University Students ◽  
Education Institution ◽  
Educational Material ◽  
Academic Achievements ◽  
The Impact ◽  
The Relationship ◽  
Development Of Students

The article reports the results of the empirical study of the impact of volitional qualities development on the level of academic achievements of higher education institution students. The article gives a theoretical analysis of the main types of volitional qualities that affect the assimilation of educational material by students. There was established the level of their development and the relationship with academic achievements. The article also identifies the main psycho-pedagogical and organizational peculiarities that affect the success of mastering the knowledge by university students. The psychological and pedagogical recommendations for forming, developing and supporting the volitional sphere of students are developed.

Study on Evolution of Plastic Deformation of Brass Band under Impact Load

2017 ◽  
Vol 753 ◽  
pp. 222-227
Author(s):  
Jun Hui Yin ◽  
Chao Xiong ◽  
Hui Yong Deng ◽  
Yan Long Zhang
Keyword(s):  
Plastic Deformation ◽  
Growth Stage ◽  
Impact Load ◽  
Recrystallization Process ◽  
Brass Band ◽  
Sexual Characteristics ◽  
Surface Metal ◽  
Band Deformation ◽  
The Impact ◽  
Meso Scale

During the moving stage of the projectile, the impact load produced by the detonation of the explosive powder acts on the ribbon, causing the plastic band deformation to occur rapidly and the surface temperature rapidly increases. In this paper, the evolution mechanism of the plastic deformation of brass band is studied, and the recrystallization process of the surface metal is still at the meso-scale scale. The recrystallization and grain growth stage sexual characteristics.

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