Transcript Slide 1

Experimental Study of Third
Body Entrapment and Its
Effect on Friction and Wear
Weiyi Wang (Michelle)
Research Assistant
Mechanical Engineering Tribology Laboratory (METL)
November 14, 2013
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Outline
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Personal background
Motivation
Objectives
Background of third body effects
Experiments
Test rig
Future work
Personal Background
• Joined METL – Aug. 2013
• B.E. Department of Precision Instruments and Mechanology
from Tsinghua University, Beijing, China – Jul. 2013
Mechanical Engineering Tribology Laboratory (METL)
November 14, 2013
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Motivation
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Third body was introduced by Godet in the 70’s to characterize the discontinuous
and heterogeneous interface that separates two bodies in contact.- M. Renouf , 2011
A. Tsouknidas, Advances in Tribology, Friction Induced Wear of Rapid
Prototyping Generated Materials: A Review, Volume 2011
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I. Sallit*, C. Richard*, R. Adam†, F. Robbe-Valloire‡, Characterization
Methodology of a Tribological Couple: Metal Matrix Composite/Brake Pads,
Materials Characterization,Volume 40, Issue 3, March 1998, Pages 169–188
Debris loosely trapped  respond kinetically to situations; transportation of debris
Mechanical functions of third bodies – protect contact surfaces
1. load carrying; 2. velocity accommodation; 3. solid lubrication, decrease wear
① Elimination of ‘natural’ screen
② First body interaction
③ Passage from two to three-body contact
④ Steady state three-body contact
Maurice Godet, Third-bodies in Tribology, Wear, 136 (1990) 29 - 45
Velocity accommodation in a
classical two-dimensional contact
Y. BERTHIER, EXPERIMENTAL EVIDENCE FOR FRICTION
AND WEAR MODELLING, Wear, 139 (1990) 77 - 92
M. Renouf , H.-P.Cao,V.-H.Nhu。 Multiphysical modeling of third-body rheology ， Tribology International 44 (2011) 417–425
Mechanical Engineering Tribology Laboratory (METL)
November 14, 2013
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Objectives
• Develop an wear model to predict the effects of third
body on wear
– Analyze the effect of different sizes and orientations of
surface textures (grooves) on wear
– Study the effects of load and sliding velocity on third
body entrapment
– Extend Modeling approach developed by Leonard et al.
• Simulate the experimentally observed effects in a
numerical / FE model
Mechanical Engineering Tribology Laboratory (METL)
November 14, 2013
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Background of Third Body Effects
Particle
detachment
Third body –
behavior inside
the contact
Flow
N. Fillot a,∗, I. Iordanoff b, Y. Berthier a，Wear modeling and the third body concept，Wear 262 (2007) 949–957
Particle
ejection
Wear
Velocity Accommodation
FB1  S1
TBS1  S2
TBb  S3
Rheological properties of debris
Influence factors
-Contact shape
-Contact conformity
-Mass of third bodies
TBS1  S2
FB1  S1
Elastic
Normal breaking
Shearing
Rolling
M1
M2
M3
M4
S: 5 sites
M: 4 modes
-Relative motion
velocity, direction
-Pressure
Competition of the
source flow and wear
flow, as functions of
the mass Mi of the
third body.
Velocity accommodation mechanisms
Y. Berthier, Experimental evidence for friction and wear modeling,
Wear, 139 (1990) 77 - 92
N. Fillot a,∗, I. Iordanoff b, Y. Berthier a，Wear modeling and the third body concept，
Wear 262 (2007) 949–957
Mechanical Engineering Tribology Laboratory (METL)
November 14, 2013
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Experiments
Variables
Groove size
Load
Sliding
velocity
Motion
① Rotational
Wear
&
Friction
Width (µm): 10, 20, 30
Depth (µm): 10, 20, 30
② Reciprocate
Mechanical Engineering Tribology Laboratory (METL)
November 14, 2013
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Test Rig
Modification on
holder for flat
contact
Instruments
Pin and disk machine Laser machine
Fixture for pins
Mechanical Engineering Tribology Laboratory (METL)
November 14, 2013
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Future Work
• Extend the experiments to more materials
• Evaluate the effect of different material properties
like yield strength, hardness etc. on wear influenced
by third bodies
• Numerical modeling of the third body effect for
different contact configurations
Mechanical Engineering Tribology Laboratory (METL)
November 14, 2013