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SUMMARY:MEchanics GAthering -MEGA- Seminar: Talk1 - Mechanisms of adhesive
  wear: A view from the nanoscale\; Talk2 - Emergence of self-affine surfac
 es under adhesive three-body wear conditions
DTSTART:20190307T161500
DTEND:20190307T173000
DTSTAMP:20260528T120254Z
UID:0037a9ad52abe229ce203068b9861f8c69986933859aa31c910fb9ee
CATEGORIES:Conferences - Seminars
DESCRIPTION:Tobias Brink & Enrico Milanes\, LSMS\, EPFL\nMechanisms of 
 adhesive wear: A view from the nanoscale by Tobias Brink\, LSMS\, EPFL\
 nAdhesive wear occurs in all sliding contacts as a result of the formation
  of local adhesive bonds between the surfaces. It is clear that material l
 oss is due to the formation of loose wear particles\, but the prediction o
 f wear rates remains challenging\, not least because the microscale mechan
 isms of wear are still poorly understood. Our research is currently center
 ed around understanding the wear particle formation as a ductile-to-brittl
 e transition\, taking the geometry and material properties of contacting s
 urface asperities into account. We use computer simulations to investigate
  the formation of these wear particles and their co-evolution with the sur
 face for dry contacts. This talk will focus on molecular dynamics simulati
 ons of the onset of debris formation\, which help us to untangle the influ
 ence of bulk and interface properties on different wear scenarios on the s
 ub-micron scale. I will discuss how these wear mechanisms could potentiall
 y result in macroscopically observed wear phenomena and what open question
 s remain.\n\n\nEmergence of self-affine surfaces under adhesive three-body
  wear conditions by Enrico Milanes\, LSMS\, EPFL\nWear of materials play
 s a key role in the durability of manufactured objects and has therefore a
 n important economic impact. A unified picture of the physics of wear is n
 onetheless still missing\, due to its high complexity: multiple phenomena 
 take place at the interface of two rubbing surfaces (ductile and brittle d
 eformation\, adhesion\, contact\, etc.) which in turn affect one another a
 nd the overall frictional behaviour. In this second part of the seminar\, 
 we will focus on the surface roughness evolution of sliding surfaces with 
 third-body formation. The study was conducted by means of long-timescale m
 olecular dynamics simulations on simple 2D model systems. We show that sur
 faces do not smooth\, rather reach a steady-state roughness and a self-aff
 ine morphology characterized by a persistent Hurst exponent. We ascribe th
 is behaviour to the interplay between ductile and brittle deformation mech
 anisms\, and to the presence of the third body. As no debris evacuation is
  allowed\, our case most closely resembles the state in closed system\, su
 ch as natural rock faults. The latter also display self-affine morphology 
 with a persistent Hurst exponent. We will also address the main difference
 s between a two-body and a three-body configuration in terms of wear volum
 e and frictional work evolution.
LOCATION:MED 2 2423 https://plan.epfl.ch/?room=MED22423
STATUS:CONFIRMED
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