Experimental Studies of Deformation and Temperature Processes Mandrelling in the Deform-3D System

2021 ◽  
Vol 1037 ◽  
pp. 357-368
Author(s):  
Mikhail F. Selemenev ◽  
Arkady A. Cherepenko ◽  
Elena A. Zvyagina ◽  
Artem N. Tkachenko ◽  
Elena M. Selemeneva
Keyword(s):  
Heat Transfer ◽  
Coefficient Of Friction ◽  
Experimental Studies ◽  
Contact Stresses ◽  
Temperature Analysis ◽  
Friction Forces ◽  
The Coefficient Of Friction ◽  
Cutting Zone ◽  
Deform 3D

The article discusses the effect of epilamated coatings during mandrelling. The picture of the change in contact stresses in the DEFORM-3D system is presented. It was established that a decrease in the coefficient of friction from 0.9 to 0.6 leads to a decrease in the number of foci and areas of contact stresses, as well as temperature analysis showed that a decrease in the friction forces reduces heat transfer in the cutting zone by about 40 ° C.

Composite multi-layer coatings for end mills

2021 ◽  
pp. 15-19
Author(s):  
M. Sh. Migranov ◽  
A.M. Migranov
Keyword(s):  
Thermal Loading ◽  
Cutting Tools ◽  
Experimental Studies ◽  
Multilayer Coatings ◽  
Wear Resistant Coatings ◽  
Milling Operations ◽  
The Coefficient Of Friction ◽  
End Mills ◽  
Cutting Zone ◽  
Coatings For Cutting Tools

The results of theoretical and experimental studies of tribological characteristics of composite multilayer coatings for cutting tools for blade processing by milling are presented. Installed reducing the coefficient of friction, longer tool life and reduced thermal loading of the cutting zone in milling operations with the use of wear-resistant coatings.

Effect of contact stress on the tribology behaviors of PTFE/316L seal pairs under various abrasive-contained conditions

2020 ◽  
pp. 135065012093751
Author(s):  
Ming-xue Shen ◽  
Bo Li ◽  
De-hui Ji ◽  
Xiao-Rong He ◽  
Xiu-zhou Lin ◽  
...  
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Contact Stress ◽  
Wear Mechanism ◽  
Considerable Effect ◽  
Contact Stresses ◽  
The Coefficient Of Friction ◽  
Three Body ◽  
Size Threshold ◽  
Invasion Behavior

This study focuses on the tribological characteristics of polytetrafluoroethylene rubbing against 316L stainless steel in the presence of various Al2O3 abrasive particles. The ranges of the contact stresses and abrasive sizes were 2.50–5.01 MPa and 2.0–230 µm, respectively. The evolution of the coefficient of friction, abrasive invasion behavior and damage characteristics on worn surfaces, and the transformation of damage mechanisms under different contact stresses are summarized. Results demonstrate that contact stress exerts a considerable effect on abrasive invasion behavior, the coefficient of friction trends become complicated at low contact stress. With decreasing particle sizes under a contact stress of 2.50 MPa, the wear failure changes from two-body wear to three-body wear, or two wear behaviors exist simultaneously. As contact stress increases, the wear mechanism is gradually simplified. The particle size threshold that causes the change of the wear mechanism is also gradually reduced. The wear rate of polytetrafluoroethylene has no linear relationship with abrasive size, whereas wear increases with contact stress. Under 2.50 MPa conditions, the particles easily invade the tribo-interface in the friction process, thus increasing the wear rate of the metallic counterpart. In addition, with increases contact stress, the polytetrafluoroethylene material transfers to the counterface, and local adhesion occurs. When the contact stress is increased to 5.01 MPa, polytetrafluoroethylene even shows an obvious creep.

On the Mechanics of Crack Initiation and Propagation in Elasto-Plastic Materials in Impact Fretting Wear

2004 ◽  
Vol 126 (2) ◽  
pp. 395-403 ◽  
Author(s):  
Y. B. Gessesse ◽  
M. H. Attia
Keyword(s):  
Crack Initiation ◽  
Contact Pressure ◽  
Coefficient Of Friction ◽  
Contact Area ◽  
Plastic Material ◽  
Oblique Impact ◽  
Fretting Wear ◽  
Isotropic Hardening ◽  
Friction Forces ◽  
The Coefficient Of Friction

Normal and oblique impact wear processes are characterized by unique features, which include the development of some residual stress components that vanish in unidirectional sliding. Parametric finite element analyses were conducted to estimate the likelihood locations for crack initiation, and the subsequent direction and rate of crack propagation in an elasto-plastic material with bi-linear isotropic hardening properties. The results showed that the increase in contact pressure can cause a significant increase in the size of the plastically deformed crack initiation zone and allows it to reach the surface. Such behavior is not predicted under continuous sliding conditions. The presence of surface friction forces in oblique impact, can also result in the development of a secondary region of high tensile stresses at the contact area. Using the crack tip slip displacement CTSD method, the rate of crack growth was found to be linearly proportional to the crack length, and significantly dependent on the contact pressure and the coefficient of friction at the crack surface. The small effect of the coefficient of friction at the micro-contact area on wear suggests that the effect of shear traction is mainly due to the increase in the depth of the crack nucleation zone. As expected, the increase of the material flow stress with strain-hardening has a wear reducing effect.

scholarly journals Method for determining the coefficient of friction between fence and scraped object in equilibrium of the friction force

2018 ◽  
Vol 19 (6) ◽  
pp. 790-794
Author(s):  
Mirosław Wolski ◽  
Tomasz Piątkowski ◽  
Przemysław Osowski
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Coefficient Of Friction ◽  
Conveyor Belt ◽  
Determination Method ◽  
Friction Forces ◽  
The Coefficient Of Friction

In this paper presents friction coefficient determination method between scraped object's material and fence material, determined directly on the conveyor belt, which then is introduced in the FEM program (LSDyna) for simulation of the scraping process in the automated sorting plant. In this case, the necessity of using an additional laboratory stand to determine the coefficient of friction is omitted. Due to the existing balance of friction forces, the model of the phenomenon can be treated as static, therefore the measurement is very simple and does not depend on time.

scholarly journals CAM FITTING UNIT OF DEVICEFOR UNSCREWING CATCHED PIPES IN THE WELL

2021 ◽  
pp. 151-164
Author(s):  
S. Yu. Gavryliv ◽  
M. M. Lyakh ◽  
Yu. L. Gavryliv
Keyword(s):  
Coefficient Of Friction ◽  
Operating Conditions ◽  
Geometric Parameters ◽  
Initial Angle ◽  
Friction Forces ◽  
Repair Work ◽  
Oil Companies ◽  
Urgent Task ◽  
The Coefficient Of Friction ◽  
The Moment

Improving the efficiency of repair work in elimination of drilling pipe accidents in the well is an urgent task of oil companies and is achieved through usage of special devices and tools. Authors patented and manufactured a device for unscrewing pipes in casing with a nominal diameter of D = 114 mm. Cycle of the device for unscrewing pipes in the well consists of three periods: freewheeling, jamming of the carrier of the device for unscrewing the trapped pipes and the period of wedging. The article analyses the operating conditions of the device locking unit during the first two periods. Formulas for determining the force of pressing the cams to the casing during freewheel, as well as the moment of friction forces and friction power for this case are proposed. We obtain the dependence of the maximum allowable initial angle of jamming on the coefficient of friction and geometric parameters of the device. It is planned to test the device for unscrewing pipes in industrial conditions of LLC "Factorial" (Poltava).

Identification of Friction Coefficient for Constrained Robotic Tasks

2002 ◽  
Vol 124 (4) ◽  
pp. 529-538 ◽  
Author(s):  
I. Sharf ◽  
G. Gilardi ◽  
C. Crawford
Keyword(s):  
Coefficient Of Friction ◽  
Normal Load ◽  
Point Contact ◽  
Contact Dynamics ◽  
Dynamics Simulation ◽  
Identification Algorithm ◽  
Test Bed ◽  
Accurate Identification ◽  
Friction Forces ◽  
The Coefficient Of Friction

Correct modeling of friction forces during constrained robotic operations is critical to high-fidelity contact dynamics simulation. Such simulations are particularly important for the development, mission planning and operations analysis of space robotic systems. Most existing friction models employ the coefficient of friction to capture the relationship between the friction force and the normal load. Hence, accurate identification of this parameter is prerequisite to accurate simulation. This issue is particularly important for space robotic operations since friction characteristics of materials are very different in space. In this manuscript, the problem of identification of the coefficient of friction is investigated experimentally and numerically. The motivating application being space manipulator systems, our principal objective is to develop a practical off-line identification algorithm, requiring minimum number of measurements from sensors available on space robots. To this end, a strategy is proposed to determine the coefficient of friction by using only the measured end-effector forces. The key idea behind the method is that during one-point contact, these forces represent the contact force and hence, can be directly used to calculate the coefficient of friction. The proposed approach is tested with the experimental data from peg insertion experiments conducted on a planar robotics test-bed with a specially designed contact interface. The algorithm is generalized to arbitrary complex geometries and applied to identify the coefficient of friction for a simulated battery drop test.

Temperature Attenuation Along Pipe Support Stanchions

2002 ◽  
Author(s):  
Chakrapani Basavaraju ◽  
Ronald C. Fox
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Coefficient Of Friction ◽  
Steam Line ◽  
Heat Transfer Analysis ◽  
Bottom Plate ◽  
Bottom Surface ◽  
Element Analysis ◽  
The Coefficient Of Friction ◽  
High Temperature Steam

High temperature steam lines in power plant piping systems are often supported by the use of pipe support stanchions welded to the steam pipe. The end of the pipe stanchion has a steel plate welded to it, which typically slides on rack steel. For vertical and guide supports, there could be considerable thermal movement in the lateral unrestrained directions, and could result in significant frictional loads. The associated frictional loads are given due consideration in piping local stress evaluations as well as in the design of pipe support structures. For some situations, it often becomes necessary to utilize a teflon-fluorogold type surface at the stanchion end plate in order to reduce the coefficient of friction and hence the frictional loads. The effectiveness of the teflon-fluorogold surface is dependent on the prevailing temperature at that surface. In situations where the stanchions on very high temperature steam lines arc relatively short, the temperature at the teflon surface of the stanchion plate could be high due to heat transfer from the steam line into the stanchion. This high temperature at the bottom surface of the stanchion plate may interfere with sliding and may eventually lead to unanticipated problems such as sticking, increase in the coefficient of friction, or unpredictable frictional behavior. In this paper, finite element analysis approach is utilized to perform heat transfer analysis and to obtain steady state temperature distribution due to decay or attenuation from the steam line surface along the stanchion. The temperature prevailing at the bottom plate surface of the stanchion is also evaluated and guidelines are provided for practical application of the results.

A Research of V-Belt Transmission Mechanics with Two Same Pulleys

2010 ◽  
Vol 450 ◽  
pp. 357-360 ◽  
Author(s):  
Qing Bao Wei ◽  
Xin Chen ◽  
Da Yu Zheng
Keyword(s):  
Coefficient Of Friction ◽  
Sliding Friction ◽  
Mechanical Analysis ◽  
Belt Drive ◽  
Equilibrium Equations ◽  
Elasticity Limit ◽  
Friction Forces ◽  
The Coefficient Of Friction ◽  
Groove Structure ◽  
Belt Transmission

V-belt is made of a special anisotropic material, its material and pulley groove structure make the V-belt drive mechanics complicated. The elasticity limit, seating and unseating effects, radial compliance makes us consider the macro features of the drive and not to consider the material heterogeneity. We focus on the steady mechanics of V-belt drive in the state of sliding friction between groove and belt. The pulley groove leads to two-dimensional radial and tangential friction forces whose direction depends on the relative speed between belt and the pulley along the contact arc. The belt model is analyzed with comparing method which is performed through acquiring the equivalent coefficient of friction, and replacing the coefficient of friction in the flat belt mechanical equilibrium equations for v-belt analysis. Through the sample calculation it is proved that this method is simple and valid for V-belt mechanical analysis.

An Empirical Model for the Coefficient of Friction in Injection Molding of Thermoplastics

2013 ◽  
Author(s):  
Omar Bataineh
Keyword(s):  
Injection Molding ◽  
Coefficient Of Friction ◽  
Empirical Model ◽  
Complex Task ◽  
Roughness Effect ◽  
Friction Forces ◽  
The Coefficient Of Friction ◽  
Ejector System ◽  
Contact Surfaces ◽  
Adhesion Effect

Predicting friction forces present between part and mold surfaces in injection molding of thermoplastics is considered an important step in the design of the ejector system. However, this requires calculating the coefficient of friction at the contact surfaces, which is usually a complex task. In this study, an empirical model is developed in an attempt to estimate the coefficient of friction as applicable for the injection molding of thermoplastics. It is assumed in this model that the coefficient of friction is a sum of two correlated effects: adhesion effect and surface roughness effect. Both effects are treated as functions of mold surface’s average asperity slope.

Friction tests in tube hydroforming

2005 ◽  
Vol 219 (8) ◽  
pp. 587-593 ◽  
Author(s):  
Yeong-Maw Hwang ◽  
Li-Shan Huang
Keyword(s):  
Internal Pressure ◽  
Coefficient Of Friction ◽  
Tube Hydroforming ◽  
Test Method ◽  
Experimental Results ◽  
Friction Test ◽  
Friction Forces ◽  
Axial Feeding ◽  
The Coefficient Of Friction ◽  
Friction Test Method

The objective of this paper is to propose a friction test method to evaluate the performance of different kinds of lubricants and determine their coefficients of friction in tube hydroforming processes. A self-designed apparatus is used to conduct the experiments of friction tests. The coefficient of friction between the tube and the die at the guiding zone is determined. The effects of the internal pressure and the axial feeding velocity on the friction forces and coefficients of friction for various lubricants are discussed. From the experimental results, it is known that MoS2 corresponding to a coefficient of friction of 0.018 is the best lubricant among the evaluated lubricants during tube hydroforming processes.

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