Publications associées à From infinitesimal to full contact between rough surfaces: Evolution of the contact area

A story of two transitions: From adhesive to abrasive wear and from ductile to brittle regime

Jean-François Molinari, Sacha Zenon Wattel

Atomistic simulations performed with a family of model potential with tunable hardness have proven to be a great tool for advancing the understanding of wear processes at the asperity level. They have been instrumental in finding a critical length scale, w ...

2024

Reliable data-driven decision-making through optimal transport

Bahar Taskesen

Decision-making permeates every aspect of human and societal development, from individuals' daily choices to the complex decisions made by communities and institutions. Central to effective decision-making is the discipline of optimization, which seeks th ...

EPFL2024

Modeling friction and wear using an adaptive discrete-continuum coupling

Manon Eugénie Voisin--Leprince

When two objects slide against each other, wear and friction occur at their interface. The accumulation of wear forms what is commonly referred to as a ``third-body''. Understanding third-body evolution has significant applications in industry, where contr ...

EPFL2024

Modeling the origins of adhesive wear across scales

Son-Jonathan Pham-Ba

Friction and wear occur at every interface between solid materials. In the design of mechanical devices, it is desirable to be able to quantify and control the amount of friction and wear, as well as predict their evolution with time. ``Tribology'' is the ...

EPFL2022

Understanding the mechanisms of adhesive wear for heterogeneous materials through atomistic simulations

Jean-François Molinari, Sacha Zenon Wattel, Antonio Joaquin Garcia Suarez

When two rough surfaces slide against each other, two main behaviors can be observed at the asperity level: A ductile behavior where the asperities tend to smooth out or a brittle behavior where the asperities detach and form debris. Recently, a critical l ...

2022

Robust numerical integration on curved polyhedra based on folded decompositions

Annalisa Buffa, Pablo Antolin Sanchez, Xiaodong Wei

We present a novel method to perform numerical integration over curved polyhedra enclosed by high-order parametric surfaces. Such a polyhedron is first decomposed into a set of triangular and/or rectangular pyramids, whose certain faces correspond to the g ...

ELSEVIER SCIENCE SA2022

A numerical study of the statistics of roughness parameters for fluctuating interfaces

Elisabeth Agoritsas

Self-affine rough interfaces are ubiquitous in experimental systems, and display characteristic scaling properties as a signature of the nature of disorder in their supporting medium, i.e. of the statistical features of its heterogeneities. Different metho ...

2021

Adhesive wear regimes on rough surfaces and interaction of micro-contacts

Jean-François Molinari, Son-Jonathan Pham-Ba

We develop an analytical model of adhesive wear between two unlubricated rough surfaces, forming micro-contacts under normal load. The model is based on an energy balance and a crack initiation criteria. We apply the model to the problem of self-affine rou ...

2021

Probabilistic and Bayesian methods for uncertainty quantification of deterministic and stochastic differential equations

Giacomo Garegnani

In this thesis we explore uncertainty quantification of forward and inverse problems involving differential equations. Differential equations are widely employed for modeling natural and social phenomena, with applications in engineering, chemistry, meteor ...

EPFL2021

Multi-scale modeling of aggregate interlock phenomena in concrete

Mohit Pundir

In concrete structures, opened cracks contribute significantly to the transfer of shear and normal stresses through the contact forces occurring between fractured surfaces. Such contact forces are due to protruding asperities, engaged by interlocking and f ...

EPFL2021

Bridging scales in wear modeling with volume integral methods for elastic-plastic contact

Lucas Henri Galilée Frérot

All mechanical systems, naturally occurring or human-produced, are subjected to friction and wear at the interface of solid constituents. Large portions of energy dissipation and loss of material, in every-day life and industrial applications alike, are du ...

EPFL2020

Instability of a thin viscous film flowing under an inclined substrate: steady patterns

Gioele Mariano Nicolò Balestra, François Gallaire, Gaëtan Pierre Clément Lerisson, Pier Giuseppe Ledda

The flow of a thin film coating the underside of an inclined substrate is studied. We measure experimentally spatial growth rates and compare them to the linear stability analysis of a flat film modelled by the lubrication equation. When forced by a statio ...

Cambridge University Press2020

A mechanistic model for the growth of cylindrical debris particles in the presence of adhesion

Jean-François Molinari, Enrico Milanese

The wear volume is known to keep increasing during frictional processes, and Archard notably proposed a model to describe the probability of wear particle formation upon asperity collision in a two-body contact configuration. While this model is largely ad ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Tribological Approach to the Watch Movements

Valentine Agnès Madeleine Magnin

Mechanical watches are complex and sensitive systems that have to maintain a faultless precision over their lifetime. However, this precision can be altered by disturbances occurring during the functioning time, such as friction, lubricant drying, or wear, ...

EPFL2020

The emergence of small-scale self-affine surface roughness from deformation

Till Junge

Most natural and man-made surfaces appear to be rough on many length scales. There is presently no unifying theory of the origin of roughness or the self-affine nature of surface topography. One likely contributor to the formation of roughness is deformati ...

AMER ASSOC ADVANCEMENT SCIENCE2020

Jamming with Tunable Roughness

Matthieu Wyart, Carolina Brito Carvalho dos Santos

We introduce a new model to study the effect of surface roughness on the jamming transition. By performing numerical simulations, we show that for a smooth surface, the jamming transition density and the contact number at the transition point both increase ...

AMER PHYSICAL SOC2020

Emergence of self-affine surfaces during adhesive wear

Jean-François Molinari, Ramin Aghababaei, Enrico Milanese, Tobias Brink

Friction and wear depend critically on surface roughness and its evolution with time. An accurate control of roughness is essential to the performance and durability of virtually all engineering applications. At geological scales, roughness along tectonic ...

Nature Research2019

Crack Nucleation in the Adhesive Wear of an Elastic-Plastic Half-Space

Jean-François Molinari, Guillaume Anciaux, Lucas Henri Galilée Frérot

The detachment of material in an adhesive wear process is driven by a fracture mechanism which is controlled by a critical length-scale. Previous efforts in multi-asperity wear modeling have applied this microscopic process to rough elastic contact. Howeve ...

PERGAMON-ELSEVIER SCIENCE LTD2020

A priori error for unilateral contact problems with Lagrange multipliers and isogeometric analysis

Annalisa Buffa, Mathieu Jonathan Fabre, Pablo Antolin Sanchez

In this paper, we consider unilateral contact problem without friction between a rigid body and deformable one in the framework of isogeometric analysis. We present the theoretical analysis of the mixed problem. For the displacement, we use the pushforward ...

2019

Mechanics of a pressure-controlled adhesive membrane for soft robotic gripping on curved surfaces

Jamie Paik, Metin Sitti, Sukho Song

This paper aims at understanding the adhesion mechanics of a pressure-controlled adhesive thin elastomeric membrane for soft robotic gripping on non-planar, curved surfaces. The adhesive elastic membrane is lined with gecko-inspired microfiber arrays and c ...

2019