ESPCI web site
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
Séminaire PMMH - Christophe Denoual, CEA
A path to model complex displacive transitions
C. Denoual1,2, N. Bruzy1,2
1-CEA, DAM, DIF, F-91297 Arpajon, France
2-Université Paris-Saclay, LMCE, F-91680 Bruyères-le-Châtel, France
Under shock loading, crystalline metals can accommodate stresses through very rapid microstructural transitions such as deformation twinning or martensitic phase transitions. These transformations occur via a collective movement of atoms (referred to as a "military" transition), typically resulting in a microstructure composed of long lamellae aligned along specific planes known as habit planes. The very limited number of crystallographic orientations observed during these transitions (e.g., 12 for twinning under shock in tantalum) arises from the limited number of possible deformation paths associated with these transitions (6 for tantalum twinning). Since these transitions lead to another well-defined crystalline structure, successive deformations can interlock, creating microstructures of remarkable complexity.
In this presentation, we will demonstrate that modeling such a transition can be achieved through a "reaction pathway graph" that represents the first n minimal-energy pathways connecting one stable phase to another. Several examples illustrating the richness of this approach will be discussed, particularly in the context of tantalum twinning under rapid loading conditions. In that case, deformation twinning is in competition with plasticity through the motion of dislocations, emphasizing the need for a detailed coupling between the graph of reaction pathways and crystal plasticity description.
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Recent seminars (8)
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Séminaire PMMH – Olga Dudko (University of California at San Diego)
Vendredi 18 avril de 11h00 à 12h00 - Salle réunion PMMH 1
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Séminaire PMMH - Máté Nagy (Eötvös Loránd University, Budapest)
Vendredi 11 avril de 11h00 à 12h00 - Salle réunion PMMH 1
Physics of animal collective behavior : interactions with one another and their environment
The breathtaking aerial displays and mesmerizing formations of birds, fish shoals and the thunderous gallop of hundreds of horses exemplify captivating group behaviors in nature. Traditional measurement methods fall short in capturing these intricate behaviors arising from simple individual interactions, (…) -
Séminaire PMMH - Máté Nagy (Eötvös Loránd University, Budapest)
Vendredi 11 avril de 11h00 à 12h00 - Salle réunion PMMH 1
Physics of animal collective behavior : interactions with one another and their environment
The breathtaking aerial displays and mesmerizing formations of birds, fish shoals and the thunderous gallop of hundreds of horses exemplify captivating group behaviors in nature. Traditional measurement methods fall short in capturing these intricate behaviors arising from simple individual interactions, (…) -
Séminaire PMMH
Vendredi 4 avril de 11h00 à 12h00 - Salle réunion PMMH 1
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Séminaire PMMH - Pascale Aussillous, Polytech' & Aix Marseille Université
Vendredi 28 mars de 11h00 à 12h00 - Salle réunion PMMH 1
Discharge Flow of a Granular Media from a Silo : Experimental investigations and continuum modeling
Silos are widely used in the industry. While empirical predictions of the flow rate, based on scaling law, exist for more than a century, recently advances have been made on the understanding of the control parameters of the flow. In particular using a continuum model together with a visco-plastic frictional (…) -
Séminaire PMMH – Charlotte de Blois (FAST, U. Paris-Saclay)
Vendredi 21 mars de 11h00 à 12h00 - Salle réunion PMMH 1
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Séminaire PMMH – Anand U. Oza (NJIT, USA)
Vendredi 14 mars de 11h00 à 12h00 - Salle réunion PMMH 1
Coarse-grained models for schooling swimmers in fast flows
The beautiful displays exhibited by fish schools and bird flocks have long fascinated scientists, but the role of their complex behavior remains largely unknown. In particular, the influence of hydrodynamic interactions on schooling and flocking has been the subject of debate in the scientific literature. I will (…) -
Séminaire PMMH - Imgard Bischofberger, MIT
Vendredi 7 mars de 11h00 à 12h00 - Salle réunion PMMH 1
Flowing through a world of patterns
Why is there so much structure, order and texture to life and nature, rather than a featureless expanse ? From microscopic snowflakes to dried mud and vast river networks, pattern formation gives rise to systems of extraordinary intricacy and beauty. Understanding how a system spontaneously selects its overall (…)
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)
