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Jean-François Molinari

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Publications associées (144)

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Adhesive wear and interaction of tangentially loaded micro-contacts

Jean-François Molinari, Tobias Brink, Son-Jonathan Pham-Ba

Current engineering wear models are often based on empirical parameters rather than built upon physical considerations. Here, we look for a physical description of adhesive wear at the microscale, at which the interaction between two surfaces comes down to ...

2020

Sliding of rough surfaces and energy dissipation with a 3D multiscale approach

Jean-François Molinari, Guillaume Anciaux

The purpose of this paper is to present a novel approach to study sliding friction by the use of 3D multiscale coupling techniques. We highlight the difficulties of using multiscale schemes that couple molecular dynamics (MD) with finite elements to perfor ...

Wiley2010

Roughness Evolution Induced by Third-Body Wear

Jean-François Molinari, Tobias Brink, Antonio Joaquin Garcia Suarez

Surface roughness is a key factor when it comes to friction and wear, as well as to other physical properties. These phenomena are controlled by mechanisms acting at small scales, in which the topography of apparently flat surfaces is revealed. Roughness i ...

2024

Emergence of self-affine surfaces during adhesive wear

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

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

A mechanistic understanding of the wear coefficient: From single to multiple asperities contact

Jean-François Molinari, Ramin Aghababaei, Lucas Henri Galilée Frérot

Sliding contact between solids leads to material detaching from their surfaces in the form of debris particles, a process known as wear. According to the well-known Archard wear model, the wear volume (i.e. the volume of detached particles) is proportional ...

2018

Critical length scale controls adhesive wear mechanisms

Jean-François Molinari, Ramin Aghababaei

The adhesive wear process remains one of the least understood areas of mechanics. While it has long been established that adhesive wear is a direct result of contacting surface asperities, an agreed upon understanding of how contacting asperities lead to w ...

Springer2016

Earthquake Nucleation along Faults with Heterogeneous Weakening Rate

Jean-François Molinari, Marie Estelle Solange Violay, Thibault Didier Roch, Mathias Alexandre David Lebihain

The transition from quasi-static slip growth to dynamic rupture propagation constitutes one possible scenario to describe earthquake nucleation. If this transition is rather well understood for homogeneous faults, how the friction properties of multiscale ...

2021

Role of interfacial adhesion on minimum wear particle size and roughness evolution

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

Adhesion between two bodies is a key parameter in wear processes. At the macroscale, strong adhesive bonds are known to lead to high wear rates, as observed in clean metal-on-metal contact. Reducing the strength of the interfacial adhesion is then desirabl ...

2020

Size and microstructure effects on the mechanical behavior of FCC bicrystals by quasicontinuum method

Jean-François Molinari

The effects of structure and size on the deformation of < 110 > tilt bicrystals in copper are investigated by concurrent multiscale simulations at zero temperature. In the simulation of eleven grain boundary (GB) structures, a direct relation is shown betw ...

2007

Microbranching instability in phase-field modelling of dynamic brittle fracture

Jean-François Molinari, Jérémy Bleyer

The microbranching instability occurring for rapidly propagating cracks in brittle materials has been described in various experiments as an intrinsically three-dimensional phenomenon. Using a variational phase-field model, we show that the microbranching ...

AIP American Institute of Physics2017

The existence of a critical length scale in regularised friction

Jean-François Molinari, Guillaume Anciaux, David Simon Kammer, Vladislav Yastrebov

We study a regularisation of Coulomb's friction law on the propagation of local slip at an interface between a deformable and a rigid solid. This regularisation, which was proposed based on experimental observations, smooths the effect of a sudden jump in ...

Elsevier2014

Predicting damage in aggregates due to the volume increase of the alkali-silica reaction products

Jean-François Molinari, Emil Gallyamov

Volume increase between the reactants and the products of alkali silica reaction could reach up to 100%. Taking place inside the aggregates, ASR imposes internal pressure on the surrounding material. In the current paper, we study the possibility of crack ...

Pergamon-Elsevier Science Ltd2022

Relations between roughness, temperature and dry sliding friction at the atomic scale

Jean-François Molinari, Guillaume Anciaux, Peter Spijker

We investigate the friction of deformable bodies, with nano-scale self-affine fractal rough surfaces, at the atomic scale using molecular dynamics. Different temperatures (0-400 K) are studied, while roughness and applied load are changed. During sliding, ...

Elsevier Sci Ltd2013

Contact between representative rough surfaces

Jean-François Molinari, Guillaume Anciaux, Vladislav Yastrebov

A numerical analysis of mechanical frictionless contact between rough self-affine elastic manifolds was carried out. It is shown that the lower cutoff wave number in surface spectra is a key parameter controlling the representativity of the numerical model ...

Amer Physical Soc2012

A non-local continuum damage approach to model dynamic crack branching

Jean-François Molinari, Nicolas Richart, Cyprien Wolff

Dynamic crack branching instabilities in a brittle material are studied numerically by using a non-local damage model. PMMA is taken as our model brittle material. The simulated crack patterns, crack velocities and dissipated energies, compare favorably to ...

Wiley2015

Influence of the meso-structure in dynamic fracture simulation of concrete under tensile loading

Jean-François Molinari, Leonardo Snozzi

We investigate the dynamic behavior of concrete in relation to its composition within a computational framework (FEM). Concrete is modeled using a meso-mechanical approach in which aggregates and mortar are represented explicitly. Both continuum phases are ...

Pergamon-Elsevier Science Ltd2011

On the influence of transgranular and intergranular failure mechanisms during dynamic loading of silicon nitride

Jean-François Molinari, Seyedeh Mohadeseh Taheri Mousavi

Plane-strain tensile loading numerical simulations of dynamic crack propagation in silicon nitride microstructures are conducted. The strength and toughness are evaluated as a function of strain rate and microstructural parameters, including grain size and ...

Elsevier2014

Numerical determination of the tensile response and the dissipated fracture energy of concrete: role of the meso-structure and inﬂuence of the loading rate

Jean-François Molinari, Leonardo Snozzi, Fabrice Gatuingt

At the mesoscopic scale, concrete can be considered as a mix of coarse aggregates with a mortar paste matrix. In this paper, we investigate numerically the influence of aggregates arrangements and loading rate on the tensile response of concrete. Each coar ...

Wiley-Blackwell2013

The cohesive element approach to dynamic fragmentation: The question of energy convergence

Jean-François Molinari

The cohesive element approach is getting increasingly popular for simulations in which a large amount of cracking occurs. Naturally, a robust representation of fragmentation mechanics is contingent to an accurate description of dissipative mechanisms in fo ...

Wiley2007

Dynamic fragmentation of ceramics, signature of defects and scaling of fragment sizes

Jean-François Molinari, Sarah Levy

Defects play a critical role in the dynamic fragmentation process of structural ceramics. Cracks initiate at seemingly random locations, propagate and coalesce to form fragments. The process is accompanied by stress release waves, whose influence is diffic ...

Elsevier2010