ESPCI web site
Le séminaire hebdomadaire du laboratoire PMMH a lieu tous les vendredis à 11h, au premier étage Barre Cassan, campus Jussieu (plan).
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France
Tel : (33) 1 40 79 45 22
Julien Scheibert (Ecole Centrale de Lyon)
Transition from static to kinetic friction : insights from numerical experiments
The contact between macroscopic rough solids is made of many micrometric asperities in contact. Under increasing shear force, each microcontact deforms, reaches its breaking threshold, and triggers a local micro-slip event. In some conditions, such an event can destabilize neighbouring microcontacts and a collective micro-slip front propagates across the interface at speeds close to that of sound in the material. Gross sliding of the solids only begins when the front has spanned the whole interface. This scenario has emerged recently from a series of pioneering experiments [1], many aspects of which are still unexplained. Here, I will present recent numerical efforts towards a better understanding of the transition from stuck to sliding interfaces.
I will first show that 2D models incorporating all boundary conditions used in experiments are required to successfully predict the triggering force and propagation length of precursors to sliding motion (Fig.). Surprisingly, this good agreement is obtained even with the minimalistic Amontons-Coulomb friction law [2,3]. In contrast, I will then show that realistic propagation speeds of micro-slip fronts are spontaneously reproduced only using more complex friction laws involving an intrinsic time scale. I will use this model to identify the sufficient physical mechanism at the origin of so-called slow fronts, discovered recently [1].
[1] S.M. Rubinstein et al., Nature (2004) ; O. Ben-David et al., Science (2010)
[2] D.S. Amundsen et al., Tribol. Lett. 45, 357-369 (2012)
[3] J. Trømborg et al., Phys. Rev. Lett. 107, 074301 (2011)
Séminaires (4)
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Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…)
Instructions générales pour les conférenciers
Le public du séminaire est très hétérogène (rien qu’au PMMH nous travaillons sur des thématiques très diverses, mécanique des fluides, des milieux granulaires, des solides, physique statistique, physique du mouillage, micro-fluidique, biophysique,...) l’objectif est donc de ne pas faire un séminaire trop spécialiste : au moins la première moitié du séminaire à un niveau accessible pour celui qui ne connaît rien sur le sujet.
Le séminaire a lieu à 11h. rendez-vous 15 minutes avant pour installer et tester la projection.
Le séminaire dure environ 45 minutes pour laisser un peu de temps pour discuter à la fin.
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