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Startseite > Séminaires > Archives séminaires > Séminaires 2014 > Séminaire MSC. Lundi 3 mars 2014. Frédéric Lechenault (LPS ENS) : "Folds and loops".

Séminaire MSC. Lundi 3 mars 2014. Frédéric Lechenault (LPS ENS) : "Folds and loops"

Sauf mention contraire, les séminaires et les soutenances se déroulent à 11h30 en salle 454A du bâtiment Condorcet.

Folds and Loops

Frédéric Lechenault : LABORATOIRE DE PHYSIQUE STATISTIQUE DE L’ECOLE NORMALE SUPERIEURE Associé au CNRS et aux Universités Paris VI et Paris VII

In this seminar, I will present two experimental situations involving the confinement of elastic objects. First I will focus on the mechanical response of a folded thin sheet. I will show that crease opening and face bending give two competing contributions to the elastic energy, which gives rise to a characteristic length scale governing the fold’s response : under tension, large origamis will bend their faces instead of actuating their angles. Then I will present some results regarding the dynamical confinement of an elastic rod in 2D : a rod is pushed in and pulled out a Hele-Shaw cell at identical velocities, keeping the confined length constant. For small confined lengths, the rod adopts an ordered, spiral-like low-energy configuration, but bifurcates towards a disordered pack of loops for large confined lengths. I will show that a naive geometric order parameter for this order/disorder transition has a well defined energy counterpart, paving the way to a complete statistical description.

Curved origami (Photo : Matt Schlian)