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
Megan T. Valentine (UCSB)
Learning from nature : how mussels stick to rocks, and what it can teach us about material design
Mussels permanently adhere to surfaces through a circular plaque that is
attached to the animal body via a long thin thread ; forming a
mushroom-shaped geometry. A plaque just a few millimeters in diameter with
a 250-micron diameter thread can withstand large pull forces of a several
Newtons without debonding. While the strength of individual chemical bonds
plays a role in determining the adhesive strength, the contact mechanics
associated with the mushroom shape is also critically important. To better
understand the role of mechanics and geometry on the adhesive strength of
mussels, we study the detachment of the mussel holdfast from glass using a
custom built load frame. This device is capable of pulling on samples along
any orientation and measuring the resulting force, while simultaneously
imaging both the bulk deformation of the plaque and the debonding
glass-plaque interface. Using this device, we measure the bond strength,
observe debonding initiation, and relate the load force to the bulk
deformation of the plaque. We find that the shape of the mussel holdfast
improves the bond strength by an order of magnitude compared to other
simple geometries and that mechanical yielding of the mussel plaque further
improves the bond strength by nearly two orders of magnitude as compared to
the strength of the interfacial chemical bonds. Mechanical tests are
complemented by ultrastructural studies using electron microscopy and
neutron scattering. These reveal the internal structure of the plaque to be
a dense interconnected network of pores, that may play important roles in
stress distribution and energy dissipation through geometric rearrangements
or fluid flow between pores. These results show that adhesive strength can
be tuned without need for interfacial chemical modification, and suggest
new pathways for synthesis of biomimetic adhesive structures.
Séminaires (5)
-
Séminaire PMMH – Vincent Bertin (IUSTI, U. Aix-Marseille)
Vendredi 6 juin de 11h00 à 12h00 - Salle réunion PMMH 1
-
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.
- Séminaires ESPCI-ENS de biophysique
- Séminaires du Département de Physique de l’ENS
- Séminaires du Laboratoire d’Hydrodynamique de l’X
- Séminaire de Mécanique d’Orsay (page web FAST)
- Séminaire de Mécanique d’Orsay (page web LIMSI)
- Séminaire de Mécanique des Fluides de l’Institut Jean le Rond d’Alembert
- Séminaires du laboratoire MSC, Paris VII
- Séminaires Gulliver
Lien vers séminaires café (internes, tous les jeudis)
