Modeling tribology: friction and fracture across scales
- Jean-François Molinari (EPFL, Lausanne, Switzerland)
- Julien Scheibert (CNRS / Ecole Centrale de Lyon, Ecully, France)
- Daniel Bonamy (CEA-Saclay, Gif sur Yvette, France)
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 various 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 Tribology 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.
- Onset of sliding: static friction, micro-slip fronts, analogy with fracture mechanics, role of interfacial heterogeneities at all scales
- Geologically-relevant friction processes: modeling friction-related processes in earthquakes, avalanches or glaciers, rock failure
- Elementary wear mechanisms: erosion, debris formation, atom-by-atom material removal
- Dissipative processes at interfaces: adhesion, viscoelasticity, plasticity, radiations, and their coupling in tribological systems
- Transient processes: instabilities, impacts, unsteady kinematics, short time scales phenomena
- Statistical aspects: fluctuations beyond the most likely behavior, predictability, intermittency, size-dependence and scaling laws
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