Formation of a High-speed Mode of Vibration Displacement of Grain During Heat Treatment

2020 ◽  
pp. 88-96
Author(s):  
Roman Kalinichenko ◽  
◽  
Serhii Stepanenko ◽  
Boris Kotov ◽  
◽  
...  
Keyword(s):  
Heat Treatment ◽  
Differential Equations ◽  
Coefficient Of Friction ◽  
High Speed ◽  
Air Flow ◽  
Support Surface ◽  
System Of Differential Equations ◽  
Vibration Displacement ◽  
The Coefficient Of Friction ◽  
Speed Mode

The article compiled and solved a system of differential equations of motion of a material point along a porous (air-permeable) surface, which is inclined at an angle to the horizon. Based on the analysis of solutions to this system of differential equations, it is proposed to change the speed of grain movement by the frequency of oscillations of the support surface, the angle of inclination of the support surface to the horizon and the coefficient of friction. Also, the graphical dependences of the speed of grain movement on the angle of inclination of the support surface to the horizon, the coefficient of friction and the frequency of oscillations were obtained. The possibility of decelerating the vibration movement of grain by an air flow, which is fed from the bottom of the porous support surface against (at an angle) the direction of grain movement, as well as using an asymmetrically corrugated support surface with vertical perforations, is theoretically substantiated. A linear regression dependence of the change in the vibration displacement speed has been experimentally determined, which makes it possible to form the required speed mode of vibration displacement of grain by changing the parameters: the inclination of the vibrating plane is 50 ÷ 90, the vibration frequency is 45 ÷ 55 s-1, the air flow speed is 0.1 ÷ 2 m/s in optimal operating modes. installations for high-intensity heat treatment of grain with a vibratory conveyor.

scholarly journals Tribological Behaviour of Sputter Coated ZnO Thin Films

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Ahalaptiya H Jayatissa ◽  
◽  
Omer Ahmed ◽  
Bodhi R Manu ◽  
Adam M Schroeder
Keyword(s):  
Heat Treatment ◽  
Coefficient Of Friction ◽  
Testing Machine ◽  
Rf Magnetron Sputtering ◽  
Zno Films ◽  
Work Piece ◽  
Tribological Behaviour ◽  
Deposition Power ◽  
The Coefficient Of Friction ◽  
Pin On Disk

The tribological properties of ZnO thin film coated on an aluminium work piece by RF magnetron sputtering were studied as a function of deposition power, substrate coating temperature, heat treatment and rotation speed. The variation in the coefficient of friction of ZnO films produced under various levels of coating parameters and conditions were experimentally determined using a pin-on-disk tribometer. The results showed that with change in deposition conditions and heat treatment, there are significant microstructural changes in ZnO films, which affect the coefficient of friction. The hardness of the prepared films was also tested using a Vickers Hardness testing machine. There was a consistent and considerable decrease in the friction coefficient of the aluminium working piece after ZnO coating. It is found that the ZnO can be used as a low friction coating material for components working under oxidative and high temperature environments.

scholarly journals Experimental study of grain vibration during high-intensity heat treatment

2020 ◽  
pp. 67-76
Author(s):  
R. A. Kalinichenko R. A. ◽  
S. P. Stepanenko ◽  
B. І. Kotov
Keyword(s):  
Heat Treatment ◽  
Mathematical Description ◽  
High Intensity ◽  
Air Flow ◽  
Experimental Studies ◽  
Statistical Processing ◽  
Material Particle ◽  
Vibration Displacement ◽  
Grain Moisture ◽  
Planning Methods

Purpose. Clarification of the mathematical description and calculation of the processes of micronization and vibrational movement of grain in cross-air flow on the basis of experimental studies. Methods. Experimental studies were performed on a manufactured sample of a machine for high-intensity heat treatment of grain using experimental planning methods and statistical processing of experimental data. Results. A mathematical description of the motion of grain mixture particles on a vibroconveyor with high-intensity heat treatment of grain during action on the mixture of air flow is given. The trajectories of particles with different sizes depending on high-intensity heat treatment are obtained. With certain assumptions, the regularities of the change in the speed of movement and exposure of the micronization of the material particle (grain) from the coordinates and humidity are obtained. Conclusions. As a result of research: 1) a regression dependence was obtained to determine the micronization exposure and it was established that the micronization exposure for the given energy parameters of the installation should last from 60 to 180 seconds; 2) the change of the speed of vibratory movement of grain depending on its humidity is theoretically substantiated and it is proved that the ascending air flow increases the speed of grain movement, and the descending one – decreases; 3) experimentally determined the empirical dependence of changes in the speed of vibration, which allows the formation of the required speed of vibration of grain by changing the parameters: the slope of the vibrating surface 5÷8°, oscillation frequency 33÷52 s-1, grain moisture 10÷20% and downward air flow rate 0.1÷2 m / s in rational modes of installation for grain micronization on a vibrating conveyor. Keywords: trajectory, vibration displacement, vibration conveyor, air flow, micronization, humidity, coefficient of friction.

scholarly journals An error analysis of the techniques used in the measurement of high-speed friction on snow

1994 ◽  
Vol 19 ◽  
pp. 19-24
Author(s):  
S. C. Colbeck
Keyword(s):  
Error Analysis ◽  
Coefficient Of Friction ◽  
Frictional Force ◽  
High Speed ◽  
Reading Speed ◽  
Air Drag ◽  
Speed Sensor ◽  
The Coefficient Of Friction

Controlled tests are needed to find the coefficient of friction of snow as a function of speed. An error analysis shows how the test must be designed to give accurate answers. It seems necessary to use a remotely controlled, aerodynamical sled in place of a skier to get accurate results. Otherwise, two sets of tests are necessary, one to determine air drag versus speed and one to determine the frictional force versus speed, and even these tests would probably not give satisfactory results. The slope used for testing should be sleep for a quick acceleration and then uniform, but not flat, where the actual measurements are taken. A continuously reading speed sensor is needed, not discrete measuring points. Even with the underlying principles understood, there will still be many practical problems to be solved before accurate results can be obtained.

Frictional Study of a High-Speed Helical Gear Pair Using Computational and Experimental Thermo-Elastic Analyses

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Jiří Dobiáš ◽  
Jan Hrubý ◽  
Jozef Kordík ◽  
Svatopluk Pták ◽  
Jan Masák ◽  
...  
Keyword(s):  
Heat Flux ◽  
Coefficient Of Friction ◽  
High Speed ◽  
Helical Gear ◽  
Temperature Fields ◽  
Stress Fields ◽  
Frictional Heat ◽  
Gear Pair ◽  
The Coefficient Of Friction ◽  
Helical Gear Pair

Abstract The paper is concerned with frictional study of a high-speed lubricated helical gear pair. The objectives were numerical evaluations of temperature and stress fields of the gear pair and the analysis of their frictional interaction in terms of the coefficient of friction. The problem was also investigated experimentally by temperature measurements at several points of a tooth. We developed an algorithm of numerical modeling based on an iterative scheme generating a sequence of approximate solutions to the temperature and stress fields till attainment of convergence of the numerically obtained and measured temperatures. Since the coefficient of friction significantly affected the frictional heat flux and thereby the temperature fields, it was used as a calibration parameter of the numerical model. Its magnitude was updated from an initial value until the one the process reached convergence with. The outcomes of the study include the temperature and stress fields, the magnitude of the coefficient of friction, and the frictional heat flux distribution.

scholarly journals An error analysis of the techniques used in the measurement of high-speed friction on snow

1994 ◽  
Vol 19 ◽  
pp. 19-24 ◽  
Author(s):  
S. C. Colbeck
Keyword(s):  
Error Analysis ◽  
Coefficient Of Friction ◽  
Frictional Force ◽  
High Speed ◽  
Reading Speed ◽  
Air Drag ◽  
Speed Sensor ◽  
The Coefficient Of Friction

Controlled tests are needed to find the coefficient of friction of snow as a function of speed. An error analysis shows how the test must be designed to give accurate answers. It seems necessary to use a remotely controlled, aerodynamical sled in place of a skier to get accurate results. Otherwise, two sets of tests are necessary, one to determine air drag versus speed and one to determine the frictional force versus speed, and even these tests would probably not give satisfactory results. The slope used for testing should be sleep for a quick acceleration and then uniform, but not flat, where the actual measurements are taken. A continuously reading speed sensor is needed, not discrete measuring points. Even with the underlying principles understood, there will still be many practical problems to be solved before accurate results can be obtained.

scholarly journals Influence of Heat Treatment and the Coefficient of Friction on the Volume of Metal Removed During Grinding Steel 35

2015 ◽  
Vol 2 ◽  
pp. 72
Author(s):  
Igor Nikiforov ◽  
Pavel Maltsev
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Coefficient Of Friction ◽  
Sliding Friction ◽  
Physical And Mechanical Properties ◽  
Abrasive Grain ◽  
Coefficient Of Sliding Friction ◽  
The Coefficient Of Friction ◽  
Relative Change

The role of external friction and chip contraction during microcutting by abrasive grain is showed. The method for determining the relative change in the coefficient of friction during grinding is proposed. The hypothesis about the influence of physical and mechanical properties and microstructure of steel 35 on the volume removes metal through the change in the coefficient of sliding friction of the chip by face of the abrasive grain is experimentally proved.

scholarly journals STUDY OF THE INFLUENCE OF FRICTION CONDITIONS ON THE INDICATORS OF THE ROLLING PROCESS IN A WIRE BLOCK

2021 ◽  
Vol 1 (38) ◽  
pp. 25-32
Author(s):  
O. Maksimenko ◽  
О. Nikulin ◽  
D. Loboiko ◽  
К. Marchenko
Keyword(s):  
Coefficient Of Friction ◽  
Deformation Zone ◽  
High Speed ◽  
Rolling Process ◽  
Alternative Possibilities ◽  
Rolled Stock ◽  
Longitudinal Stability ◽  
Wire Rod ◽  
The Coefficient Of Friction ◽  
The Wire

Physical modeling of the laws of friction during pressure treatment is a complex problem and is solved with many restrictions and assumptions. Computational experiments open up alternative possibilities for investigating the influence of friction conditions on the rolling process. A deeper analysis of the friction mechanism in the wire block is required, since there is a significant scatter in the data on the coefficient of friction during high-speed rolling of wire rod. The aim of this work is to study the influence of friction conditions in the deformation zone of each of the stands of the wire block on the change in specific tensions, on the longitudinal stability of the rolling process, on the change in the angle of the neutral section and on the broadening of the metal. The study of the influence of these factors is based on the joint solution of the differential equilibrium equation of the elementary volume, isolated in the deformation zone, the plasticity equation. In this work, the range of variation of the coefficient of friction was chosen such as to reveal the patterns of rolling in conditions close to the limiting. The work investigated the influence of the coefficient of friction on the parameters of rolling wire rod with a diameter of 5.5 mm in a wire block. The study was carried out with a change in the coefficient of friction from 0.22 to 0.18 during the rolling of one roll. The friction conditions in the deformation zones of the wire block, affect the tension of the roll, affect both the transverse flow of the metal, and the reduction. The study of the process of rolling wire rod in a wire block showed that a toughening of the friction mode in contact between the metal and the rolls increases the longitudinal stability of the rolled wire in the deformation zone. The minimum value of the friction coefficient at which the process remains stable without loss of equilibrium is close to 0.2. With a decrease in the coefficient of friction, the tension of the metal in the inter-stand spaces sharply increases, which can lead to partial or complete slipping of the strip. The friction conditions in the contact between the rolls and the rolled stock affect the coefficient of transverse deformation and reduction of the metal in the stands of the wire block, as well as the power parameters.

Projectile Mass Loss Model Using the Coefficient of Friction for High-Speed Penetration into Concrete

2014 ◽  
Vol 566 ◽  
pp. 365-370
Author(s):  
Fei Qian ◽  
Hai Jun Wu ◽  
Feng Lei Huang ◽  
Ai Guo Pi ◽  
Xiu Fang Ma
Keyword(s):  
Mass Loss ◽  
Friction Force ◽  
Coefficient Of Friction ◽  
High Speed ◽  
Calculated Data ◽  
Analytical Estimate ◽  
The Coefficient Of Friction ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
Work Done

In this paper, a model of the friction coefficient in the high-speed penetration process has been used, which considers the micro-asperities of the projectile surface, the adiabatic shearing and the heat conduction on the nose of projectile. It also considers that the coefficient of friction is a function of the sliding velocity. Then, an analytical model of mass loss based on the coefficient of friction and the revised dynamic spherical cavity expansion theory of the concrete material is constructed. An analytical estimate for the work done by friction force in the penetration could be calculated and the evaluation of mass loss of projectile could also be calculated by the heat translated from the work done by friction force. Finally, a comparative analysis between the calculated data and the experimental data of mass loss is done.

scholarly journals Characteristics of a Tire Friction and Performances of a Braking in a High Speed Driving

2014 ◽  
Vol 6 ◽  
pp. 260428 ◽  
Author(s):  
Yumrak Oh ◽  
Hoguen Lee
Keyword(s):  
Coefficient Of Friction ◽  
High Speed ◽  
Skid Resistance ◽  
Conservation Of Energy ◽  
Driving Speed ◽  
The Coefficient Of Friction ◽  
Braking Distance ◽  
The Difference ◽  
Tire Friction ◽  
Safe Road

The goal of pavement is to deliver the fine roughness and the safe road surface to traffic. It requires a secured and comfortable surface using the controlled speed of road. Through adjusting driving speed, skid resistance can be altered in one of the performances of the pavement surface. In high speed driving, there might be a certain level of risk, not in the same level as the proposed roads. Hence, this study first analyzes the speed equation under a consideration of a braking distance and then suggests the friction coefficient in high speed driving with the principle of conservation of energy. If we accept simply that the coefficient of friction is independent of speed, the difference between analysis and test value for braking distance is greatly generated. Therefore we have to analyze the coefficient of friction as an exponential function of braking speed of a vehicle.

Oblique Impact of Thick Walled Pressurized Spheres as Used in Tennis

2005 ◽  
Vol 219 (11) ◽  
pp. 1179-1189 ◽  
Author(s):  
S J Haake ◽  
M J Carré ◽  
R Kirk ◽  
S R Goodwill
Keyword(s):  
Coefficient Of Friction ◽  
Momentum Flux ◽  
High Speed ◽  
Reaction Force ◽  
Oblique Impact ◽  
Tennis Ball ◽  
The Coefficient Of Friction ◽  
Impact Phase ◽  
Rotation Set ◽  
The Impact

A model is presented in which the normal impact of a thick walled pressurized sphere, such as a tennis ball, is modelled as a non-linear viscoelastic spring and damper, coupled with momentum-flux forces where the shell wall deforms with high stiffness and damping. These momentum-flux forces are only present in the impact phase and do not appear during restitution. Rotation set up during an oblique impact causes the momentum-flux forces at the front and rear of the sphere to be different such that the total vertical reaction force acts in front of the centre of mass when topspin is present. The sphere was allowed to deform and this caused both the torque and the effective moment of inertia of the sphere to decrease. The result of this is that the deformed sphere gains sufficient spin during impact for reverse slip to occur when the ball reforms towards the end of impact. Tennis balls were projected at two similarly constructed surfaces with a coefficient of friction of 0.51 and 0.62. It was found that displacements and rotations from the model compared well with experimental results recorded using a high-speed video running at 7100 frames per second. The model was able to predict these results with only the coefficient of friction as the varying parameter.

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