Friction Coefficient as a Macroscopic View of Local Dissipation

2007 ◽  
Vol 129 (4) ◽  
pp. 829-835 ◽  
Author(s):  
D. Richard ◽  
I. Iordanoff ◽  
Y. Berthier ◽  
M. Renouf ◽  
N. Fillot
Keyword(s):  
Friction Coefficient ◽  
Dry Friction ◽  
Three Dimensional ◽  
Third Body ◽  
The Third ◽  
Dynamic Friction Coefficient ◽  
Approaches To Study ◽  
Set Up ◽  
Method Approach ◽  
Simple Interaction

This paper presents an overview of a discrete element method approach to dry friction in the presence of a third body. Three dimensional computer simulations have been carried out to show the influence of the third body properties (and more specifically their adhesion) on friction coefficient and profiles of dissipated power. Simple interaction laws and a cohesive contact are set up to uncouple the key parameters governing the contact rheology. The model is validated through a global energy balance. As it is shown that dynamic friction coefficient can be explained only in terms of local energy dissipation, this work also emphasizes the fact that mechanism effects and third body rheology have important consequences on the energy generation and dissipation field. Therefore, asymmetries can arise and the surface temperature of first bodies can be significantly different even for the same global friction coefficient value. Such investigations highlight the fact that friction coefficient cannot be considered in the same way at the mechanism scale as at the contact scale where the third body plays a non-negligible role, although it has been neglected for years in thermal approaches to study of surfaces in contact.

Friction Coefficient as a Macroscopic View of Local Dissipation

2007 ◽  
Author(s):  
I. Iordanoff ◽  
D. Richard ◽  
M. Renouf ◽  
Y. Berthier
Keyword(s):  
Friction Coefficient ◽  
Dry Friction ◽  
Three Dimensional ◽  
Global Scale ◽  
Contact Interface ◽  
Third Body ◽  
The Third ◽  
Dynamic Friction Coefficient ◽  
Set Up ◽  
Method Approach

This paper presents an overview of a Discrete Element Method approach used to study the dry friction (global scale) taking into account local discontinuity with the presence of third body at the contact interface. Three dimensional computer simulations have been carried out to show the influence of the third body properties (and more specifically its adhesion) on the resulting friction coefficient as well as the dissipated power profiles. The physics of the interface is described by a simple cohesive contact law which is set up to uncouple the key parameters governing the contact rheology. The model is validated through a global energy balance. As it is shown that dynamic friction coefficient can be explained in term of local energy dissipation, the work also emphasizes the fact that mechanism effects and third body rheology have important consequences on the energy generation and dissipation field. The friction coefficient cannot be considered the same way at the mechanism scale than at the contact one where the third body plays a non-negligible role despite the fact that it has been neglected for years in thermal approaches of the contact.

A Novel Three-Dimensional Finite Element Model to Simulate Third Body Effects on Fretting Wear of Hertzian Point Contact in Partial Slip

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Arman Ahmadi ◽  
Farshid Sadeghi
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Three Dimensional ◽  
Point Contact ◽  
Fretting Wear ◽  
Partial Slip ◽  
Wear Particles ◽  
Third Body ◽  
Stick Slip ◽  
The Third

Abstract In this investigation, a finite element (FE) model was developed to study the third body effects on the fretting wear of Hertzian contacts in the partial slip regime. An FE three-dimensional Hertzian point contact model operating in the presence of spherical third bodies was developed. Both first bodies and third bodies were modeled as elastic–plastic materials. The effect of the third body particles on contact stresses and stick-slip behavior was investigated. The influence of the number of third body particles and material properties including modulus of elasticity, hardening modulus, and yield strength were analyzed. Fretting loops in the presence and absence of wear particles were compared, and the relation between the number of cycles and the hardening process was evaluated. The results indicated that by increasing the number of particles in contact, more load was carried by the wear particles which affect the wear-rate of the material. In addition, due to the high plastic deformation of the debris, the wear particles deformed and took a platelet shape. Local stick-slip behavior over the third body particles was also observed. The results of having wear debris with different material properties than the first bodies indicated that harder wear particles have a higher contact pressure and lower slip at the location of particles which affects the wear-rate.

Physico-Chemical Modeling of Third Body Rheology

2010 ◽  
Author(s):  
Mathieu Renouf
Keyword(s):  
Third Body ◽  
Unknown Parameters ◽  
Chemical Modeling ◽  
The Third ◽  
Real Contact ◽  
Physico Chemical ◽  
Role Concerns ◽  
Set Up ◽  
Discrete Element Methods ◽  
Two Bodies

The well-known concept of third body was introduced by Godet in the seventies to characterise the discontinuous and heterogeneous interface that separates two bodies in contact. This thin layer (from some nanometers to some micrometers high) appears to possess its own rheology depending of contact conditions, material properties and often, extra unknown parameters. If its main common role concerns essentially mechanical aspects such as velocity accommodation, load carrying capacity and solid lubricant, it plays an important role in other physical aspects. For example, it ensures the thermal continuity between two bodies in contact and explains the jump of temperature observed experimentally. Moreover, it is able to capture the maximal temperature through its thickness. Due to the difficulty to instrument a real contact without disturbing the local rheology, observations of the third body rheology occur only on simplified experimental set-up. To reproduce and try to understand “real contact in presence of third body”, numerical tools have been developed and adapt to face new challenge raised by the third-body concept. The discontinuity and heterogeneity of such interface led researchers to use discrete element methods (DEM) to describe its evolution. Several improvments of the method allow to deal with the mechanical and the thermal behaviour of such media but without interactions. The integration of physicochemical aspects is presented in the paper to link thermal and mechanical behaviour and proposed a model able to represent the multi-physical feature of a contact interface.

Effects of fretting wear on porous Ti materials by using rice husk as hold space

2020 ◽  
Vol 10 (3) ◽  
pp. 396-403
Author(s):  
Xinsheng Wang ◽  
Zhen Lin Lu ◽  
Jia Lei
Keyword(s):  
Friction Coefficient ◽  
Bovine Serum ◽  
Dry Friction ◽  
Three Dimensional ◽  
Pure Titanium ◽  
Porous Titanium ◽  
Fretting Wear ◽  
Wear Volume ◽  
Porous Ti ◽  
Wear Tests

A comparative analysis of the friction coefficient of pure and porous titanium was carried out through wear tests conducted both in dry friction conditions and using a bovine serum lubricant friction conditions. The microstructure, wear mechanism and three-dimensional topography of the two specimens were studied. In pure and porous titanium, the results show that the friction coefficient, wear volume and roughness were higher in dry friction than in the presence of lubrication for both pure and porous titanium. However, in dry friction and bovine serum lubricant tested, the resistance of pure titanium was higher than that of porous titanium.

Experimental Thermal Study of Contact With Third Body

2005 ◽  
Author(s):  
D. Majcherczak ◽  
P. Dufrenoy ◽  
Y. Berthier
Keyword(s):  
Infrared Camera ◽  
Thermal Study ◽  
Third Body ◽  
The Third ◽  
Complex Interactions ◽  
Fixed Ring ◽  
Physico Chemical ◽  
Set Up ◽  
Generation Mechanisms ◽  
Electronic Microscope

The thermal study of sliding contact is complex due to numerous physical aspects highly coupled. Heat generation mechanisms are still badly known due to the complex interactions between mechanical, thermal and physico-chemical behaviours and surface degradations. In the goal to better appreciate the third body role on the thermal aspect, an experimental set-up has been realized. It consists in two rings sliding to each other, the first one is made of sapphire (rotating ring) and the second one is made of steel (fixed ring). The temperatures are obtained by an infrared camera scanning through the sapphire and by thermocouples on the contact surface specially realized for this experimental setup. The contact surfaces of the two rings have been observed with a scanning electronic microscope. Comparison between the thermal scene and the surface observations has allowed connecting the third body accumulation with local surface heating.

Modeling of Friction Induced Vibration due to Third-Body Effects

2001 ◽  
Author(s):  
David S. Xu ◽  
Hooshang Heshmat
Keyword(s):  
Friction Coefficient ◽  
Normal Load ◽  
System Response ◽  
Viscous Damping ◽  
Third Body ◽  
The Third ◽  
Damping Material ◽  
Variable Friction ◽  
Semi Empirical ◽  
Friction Induced Vibration

Abstract Friction induced vibration at contact interfaces is still a big challenging problem and not well understood how to affect the high cycle fatigue (HCF) failures in gas turbine engine and other machinery. Most researchers conducted on the subject of only two bodies in contact with the Coulomb’s friction law only. In this paper, the interface friction phenomena and induced vibration are investigated by means of the improved third-body composite interface micro-slip model which includes a variable friction coefficient and a flexible contact, represented as effective stiffness and equivalent viscous damping elements. The third-body considered herein is almost always present at contacting interfaces and is comprised of generated wear debris or a soft intermediate anti-fretting coating applied to the mating surfaces. This kind of third-body can be viewed as a thin factional damping material layer to provide shear energy dissipation in order to mitigate the destructive effects of high frequency vibrations in components with highly stressed contacts. A properly engineered third-body can also play the role of both a damping material and a lubricant to decrease wear rate. For the study presented, a semi-empirical formula for the third-body powder properties was employed, depending on the experimental data and the non-linear regression approach. The experimental powder TiO2 data included density, shear strength, frictional coefficients, loss factor as a function of normal load, shear strain, speed and frequency. The results in this paper indicate that the third body semi-empirical equivalent stiffness / viscous damping representation of a flexible contact with variable friction coefficient does indeed have merit and does have influence on overall system response. It has been shown that the third body effects should be considered in the friction and damping induced vibration on the contact interfaces. Such a model may be used to assess designs and material coating approaches to counter fretting in highly stressed contacts as well as assessing the interaction of contact kinematics on HCF failures. Further experimental investigation of specified friction contact configuration of the components needs to be conducted in order to evaluate their friction characteristics and move this technology toward a practical engineering applications.

Dynamics Research on Tape Feeder of Placement Machine

2010 ◽  
Vol 156-157 ◽  
pp. 203-206 ◽  
Author(s):  
Yong Shan Xiao ◽  
Zhen Yu Zhao ◽  
Fu Min Song
Keyword(s):  
Friction Coefficient ◽  
Great Influence ◽  
Static Friction ◽  
Prototype Model ◽  
Motor Torque ◽  
External Torque ◽  
Dynamic Friction Coefficient ◽  
Set Up ◽  
Placement Machine ◽  
The Impact

Based on multi-body dynamics, the virtual prototype model of the tape feeder is set up, and the impact of the external torque and the friction coefficient on the whole system is analyzed. Simulation results show that the external torque has great influence on the required motor torque: when the external torque increases from 50N.mm to 200N.mm, the required motor torque increases from 75.217N.mm to 223.98N.mm. The friction damping also has great influence on the motor torque: when the dynamic friction coefficient increases from 0.001 to 0.009 and the static friction coefficient increases from 0.003 to 0.011, the required motor torque increases from 106.92N.mm to 158.81 N.mm.

Study on the Lubrication and Antifriction Mechanism of Low Frictional Self-Lubricating Wear-Resisting Coating

2011 ◽  
Vol 339 ◽  
pp. 477-482 ◽  
Author(s):  
Yun Cai Zhao ◽  
Shu Feng Huang ◽  
Xiao Mei Liu
Keyword(s):  
Friction Coefficient ◽  
Friction Factor ◽  
Room Temperature ◽  
Abrasive Particle ◽  
Surface Texturing ◽  
Laser Remelting ◽  
Third Body ◽  
The Third ◽  
Abrasion Loss ◽  
Supersonic Plasma

This paper is about the lubricating wear-resisting coating KF301/WS2 and round pit texturing modified coating KF301/WS2 which are prepared by supersonic plasma spraying, laser remelting and surface texturing technology, tribological characteristics of two kinds of coatings are studied under room temperature, according to this, it is discussed for lubrication antifriction mechanism. The research shows: round pit texture has a certain influence on friction factor of coating’s surface and abrasion loss. Friction coefficient of untextured surface is about 0.0138 in the initial stages, while friction coefficient of round pit texture is about 0.01, compared with the former, the latter decreases 27%; when wear time reaches to 1 hour, abrasion loss of untextured surface is 0.0026mg, while abrasion loss of round pit texture is about 0.013mg, compared with the former, the latter decreases 50%. The lubricant antifriction performance of round pit texture is higher than untextured surface, this is because friction coefficient of coating is decreased as the change of the third-body bed, and round pit micro moulding can collect abrasive particle, decreasing the influence of abrasive particle.

Third Body Concept and Wear Particle Behavior in Dry Friction Sliding Conditions

2015 ◽  
Vol 640 ◽  
pp. 1-12 ◽  
Author(s):  
Jean Denape
Keyword(s):  
Dry Friction ◽  
Friction And Wear ◽  
Wear Particle ◽  
Phenomenological Approach ◽  
Wear Particles ◽  
Third Body ◽  
Practical Applications ◽  
The Third ◽  
Body Concept ◽  
Synthetic View

The third body concept is a pragmatic tool for analyzing and understanding the friction and wear of sliding materials. This approach is based on the dominating role played by the wear particles under dry sliding conditions. These particles constitute the major part of what is called the third body. The third body concept was introduced by Maurice Godet in the middle of the 70’s and developed by Yves Berthier since the end of the 80’s who added complementary conceptual tools as the tribological triplet, the accommodation mechanisms and the tribological circuit. The aim of this paper is to give a synthetic view of these concepts, which involves mechanical, material and physicochemical subjects. Concrete examples and case studies from various practical applications are given to illustrate the validity and the efficiency of such a phenomenological approach.

scholarly journals Analysis of surface structure of zirconia crystals in case of friction against steel

2020 ◽  
Vol 329 ◽  
pp. 02008
Author(s):  
Valery Alisin ◽  
Mikhail Borik ◽  
Alexey Kulebyakin ◽  
Elena Lomonova ◽  
Irina Suvorova
Keyword(s):  
Dry Friction ◽  
Friction Surface ◽  
Friction Pair ◽  
Base Material ◽  
Electron Microscopic Examination ◽  
Third Body ◽  
Electron Microscopic ◽  
The Third ◽  
Transfer Films ◽  
Friction Surfaces

The article considers the formation of the third body during dry friction of the nanostructured zirconia crystals partially stabilized with yttria against steel. The assumption is substantiated that the tribological properties of the studied friction pair are determined by the properties of the films formed on the surface of the crystals. Friction tests under sliding conditions were performed according to the “disk-finger” scheme. The results of electron microscopic examination of the friction surfaces of crystals are presented. The elemental composition was determined, and the phase composition of the transfer films of various sections of the crystal friction surface was calculated. At high magnifications, it was found that the friction surface of samples with 2-4 mol.% of Y2O3 has the sufficiently homogeneous structure of the films with traces of boundaries of smaller particles of the transferred material. Destruction of the friction surface of a sample with a Y2O3 content of 8 mol.% occurs at a deeper level and affects not only the layer of secondary structures, but also the underlying layers of the base material.

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