Daniele Savio
University of Lyon
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Publication
Featured researches published by Daniele Savio.
Tribology Letters | 2012
Daniele Savio; Nicolas Fillot; Philippe Vergne; Maurizio Zaccheddu
It is shown via molecular dynamics simulations that the occurrence of wall slip for linear alkanes confined between geometrically smooth surfaces depends on the wall-fluid interactions and the chain length of the lubricant molecules. A wall slip model based on the competition between these two factors is introduced. A surface parameter accounts for the wall-fluid interaction and commensurability, and is valid for both canonical and complex crystal lattices: this quantity is then linked to the shear stress transferred to the fluid molecules. The lubricant internal cohesion under confinement is described by a bulk viscosity term. Finally, a semi-analytical law for wall slip prediction including both the fluid viscosity and the surface characterization parameter is proposed.
Tribology Letters | 2013
Daniele Savio; Nicolas Fillot; Philippe Vergne
The transition from ultra-thin lubrication to dry friction under high pressure and shear is studied using molecular dynamics: the quantity of lubricant in the confined film is progressively reduced toward solid-body contact. A quantized layer structure is observed for n-alkanes confined between smooth, wettable walls, featuring an alternation of well-layered, low friction configurations, and disordered ones, characterized by high friction, and heat generation. The molecular structure influences the ordering of the fluid and the resulting shear stress. In fact, Lennard-Jones fluids are characterized by low friction due to the absence of interlayer bridges, opposed to the always entangled states and high shear stresses for branched molecules. Surface geometry and wettability also affect the behavior of the confined lubricant. The presence of nanometer-scale roughness frustrates the ordering of the fluid molecules, leading to high friction states. Furthermore, local film breakdown can be observed when the asperities come into contact, with strong wall–wall interactions causing the maximum in shear stress. Finally, friction is limited to a small, constant value by the presence of smooth, non-wettable surfaces in the system due to the occurrence of wall slip.
ASME/STLE 2012 International Joint Tribology Conference | 2012
Daniele Savio; Nicolas Fillot; Philippe Vergne; Maurizio Zaccheddu
Reduction of the oil quantity in lubricated contacts Film thickness decreases Transition from full-film lubrication to solid body contact Mixed lubrication regime What happens in the contact zones? Molecular Dynamics modeling of local film breakdown Frictional behavior of the last fluid layers under shear Influence of nano-roughness on the walls
Tribology Frontiers Conference | 2014
Nicolas Fillot; Daniele Savio; Philippe Vergne
7th International Conference, on Multiscale Materials Modeling | 2014
Philippe Vergne; Daniele Savio; Nicolas Fillot
Influence of Interfacial Interactions on Structural and Rheological Properties of Confined Liquids | 2013
Nicolas Fillot; Daniele Savio
5th World Tribology Congress, WTC2013 | 2013
Daniele Savio; Nicolas Fillot; Philippe Vergne; Hartmut Hetzler; Wolfgang Seemann; Rihart Pasaribu; Guillermo E. Morales-Espejel
5th ELyT lab Workshop | 2013
Daniele Savio; Nicolas Fillot; Philippe Vergne
2012 ECI Conference "Advances in Lubrication: Linking Molecular, Meso, and Machine Scales" | 2012
Daniele Savio; Nicolas Fillot; Philippe Vergne
38th Leeds-Lyon Symposium on Tribology, "Energy and Health" | 2011
Daniele Savio; Nicolas Fillot; Philippe Vergne