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PMMH’s weekly seminar is held every Friday at 11 am (map)
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 Chopin (Universidade Federal do Rio de Janeiro)
Morphological instabilities of a stretched twisted ribbon
Finding strategies toward developing functional shapes at smaller and smaller scales has been a focus of intense research in elastic materials. Our investigations show that a wide variety of shapes and instabilities can be obtained by simply varying the applied twist and tension [1]. Due to its geometry which is intermediate between rod and plate, a ribbon can coil and form loops but wrinkles and stress localization can also been seen yielding a surprisingly rich variety of shapes. Using the twist angle, the tension, the thickness and the length as control parameters, the various configurations including longitudinal and transverse wrinkling, and creasing can be rationalized in a 4D phase diagram. We show that this experimental phase diagram can be quantitatively explained using a theoretical framework based on (i) a covariant form of the Föppl-von Kàrmàn equations which is necessary to obtain the correct stress field ; and (ii) a far from threshold analysis which describes a longitudinally-wrinkled state with negligible compression [2]. Our study has both impact on fundamental theory of thin elastic materials [3] and development of smart, reliable, and efficient strategy to build complex structures starting with graphene sheets, and flat semiconductor nanoribbons and biomaterials.
Figure 1 Typical morphologies of ribbons subjected to twist and stretching : (a) helicoid, (b,c) longitudinally wrinkled helicoid, (d) creased helicoid, (e) formation of loops and selfcontact zones, (f) cylindrical wrapping, (g) transverse buckling and (h) twisted towel shows transverse buckling/wrinkling (from Ref.[2]).
[1] J. Chopin and A. Kudrolli, Phys. Rev. Lett. 111, 174302 (2013),
URL : http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.107.208304
[2] J. Chopin, V. Démery, and B. Davidovitch, ArXiv e-prints, 1403.0267 (2014),
URL : http://arxiv.org/abs/1403.0267
[3] C. Santangelo, Journal Club for Condensed Matter Physics (2014),
URL : http://www.condmatjournalclub.org/?p=2330
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Seminars (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 (…)
The audience is composed of people with rather heterogeneous backgrounds including specialists in solids, fluids, granular flows, statistical physics... so the idea is to keep your talk understandable by people not necessarily working in your field... The seminar time slot runs from 11am to noon so the best is to make the talk last around 45 minutes to leave some time for discussion.
- 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
Link to cofee seminar (internal, every Thursday)
