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Workshops

Modeling tribology: friction and fracture across scales

January 28, 2019 to January 30, 2019
Location : CECAM-HQ-EPFL, Lausanne, Switzerland
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Organisers

  • Jean-François Molinari (Swiss Federal Institute of Technology of Lausanne (EPFL), Switzerland)
  • Julien Scheibert (CNRS / Ecole Centrale de Lyon, France)
  • Daniel Bonamy (CEA, France)

Supports

   CECAM

Description

Tribology, the science of contacting surfaces, remains poorly understood. The challenge lies in the intrinsic multi-scale and multi-physics nature of friction. Tribological systems may cover:

(i) Length scales from nanometers (atomistic and molecular mechanisms at micro- or nano-contact levels) to kilometers (fault seismicity)

(ii) Time scales from picoseconds (tribo-induced chemical reactions) to years (earthquake cycle)

(iii) A variety of coupled processes including phase changes, fluid flow, complex rheologies of the contacting materials, fragmentation and third body formation.

The ambition of the proposed workshop is to clarify the nature, validity range and coupling of the many elementary processes involved in tribological systems at all space and time scales. A special emphasis will be put on identifying how the tools used in the fracture mechanics community (e.g. equation of motion for crack propagation, size-dependent fracture modes, rupture of heterogeneous media) can help in describing tribological processes.

To achieve these goals, the workshop will gather researchers active in either or both the friction and fracture fields, coming from the Physics, Geophysics, Mechanics and Engineering communities. The main focus will be on the modeling (both numerical and theoretical) aspects, and relevant experimental results will serve as a preliminary basis for extensive discussions.

 

Key topics:

  1. Onset of sliding: static friction, micro-slip fronts, analogy with fracture mechanics, role of interfacial heterogeneities at all scales
  2. Geologically-relevant friction processes: modeling friction-related processes in earthquakes, avalanches or glaciers, rock failure
  3. Elementary wear mechanisms: erosion, debris formation, atom-by-atom material removal
  4. Dissipative processes at interfaces: adhesion, viscoelasticity, plasticity, radiations, and their coupling in tribological systems
  5. Transient processes: instabilities, impacts, unsteady kinematics, short time scales phenomena
  6. Statistical aspects: fluctuations beyond the most likely behavior, predictability, intermittency, size-dependence and scaling laws

References

Selected references:

V. Gabuchian, A.J. Rosakis, H.S. Bhat, R. Madariaga, H. Kanamori, “Experimental evidence that thrust earthquake ruptures might open faults”, Nature 545, 336, 2017.

R. Aghababaei, D.H. Warner, J.F. Molinari, “On the debris-level origins of adhesive wear”, PNAS, in press, 2017.

R. Aghababaei, D.H. Warner, J.F. Molinari, “Critical length scale controls adhesive wear mechanisms”, Nature Communications 7, 11816, 2016.

J. Barés, A. Dubois, L. Hattali, D. Dalmas & D. Bonamy, “Aftershock sequences and seismic-like organization of acoustic events produced by a single propagating crack”, Nature Communications 9, 1253, 2018.

J.K. Tromborg, H.A. Sveinsson, J. Scheibert, K. Thogersen, D.S. Amundsen, A. Malthe-Sorenssen, “Slow slip and the transition from fast to slow fronts in the rupture of frictional interfaces”, PNAS 111, 24, 8764-8769, 2014.

I. Svetlizky, J. Fineberg, “Classical shear cracks drive the onset of dry frictional motion”, Nature 509, 7499, 205-208, 2014.

L. Pastewka, M.O. Robbins, “Contact between rough surfaces and a criterion for macroscopic adhesion”, PNAS 111, 9, 3298-3303, 2014.

A. Vanossi, N. Manini, E. Tosatti, “Static and dynamic friction in sliding colloidal monolayers”, PNAS 109, 16429–16433, 2012.

Y. Mo, K.T. Turner, I. Szlufarska, “Friction laws at the nanoscale”, Nature 457, 7233, 1116-1119, 2009.