Come to PMMH laboratory: www.pmmh.espci.fr/Contact-357
Next Seminars:
27 Février : Vacances d’Hiver
6 Mars : Vacances d’Hiver
13 Mars : Christophe Gissinger (LPENS)
20 Mars : Cédric Beaume (U. Leeds)
27 Mars : Philippe Beltrame (U. Avignon)
Full list at www.pmmh.espci.fr/Seminaires.
These results show that the friction is important for the emergence of both the subcritical bifurcation and the hula-hoop-like motion.
We propose a phenomenological model of this phenomenon that includes the effect of friction at the rotation axis. The model produces behaviors similar to the experimental results, such as the hula-hoop-like motion of the camphor-coated disk and the subcritical bifurcation.
i.e., the camphor-coated disk remains at rest when the water depth is shallow, rotates when sufficiently deep, and exists in both the rotational and rest states at the intermediate depth. The camphor-coated disk exhibits a hula-hoop-like motion as it rotates.
When an elliptical camphor-coated paper disk, with the center of mass fixed at the axis of rotation, is placed on the surface of water, it rotates spontaneously with a constant angular velocity. In experiments involving different water depths, we found that a subcritical bifurcation occurs;
The PMMH on Friday 20 Feb at 11:00 will be given by
Michiko Shimokawa of the Nara University, Japan on
Transition on bifurcation phenomena observed in experiments with a rotating elliptical camphor coated disk
Abstract below. Zoom link upon request.
(ii) On a solid surface, we investigate flammable droplets in the Leidenfrost state. The influence of the flame on the droplet lifetime is measured and rationalized.
As an appetizer, we describe the interaction between a droplet and cotton candy, focusing on its interaction with sugar fibers.
(i) Instead of a solid plate, the hot substrate is replaced by a granular material. Under specific conditions, the droplet begins to dig into the granular bed.
This phenomenon, known as the Leidenfrost effect, can be observed when a water droplet is deposited on a hot pan.
We will explore several unusual manifestations of the Leidenfrost effect.
A volatile liquid placed near a heat source generates vapor. This vapor forms a thin film that dramatically reduces heat transfer between the surface and the droplet. As a result, the droplet does not boil.
#### Come to PMMH laboratory: www.pmmh.espci.fr/Contact-357
#### Next Seminars
February 20th: Michiko Shimokawa (U. Nara, Japan)
March 13th: Christophe Gissinger (LPENS)
March 20th: Cédric Beaume (U. Leeds)
March 27th: Philippe Beltrame (U. Avignon)
Full list at www.pmmh.espci.fr/Seminaires.
The PMMH seminar on Friday 13 Feb at 11:00 will be given by Stéphane Dorbolo, Liège University, Belgium.
Title: Droplet in Hostile Territory
Zoom link upon request. Abstract follows.
#### Come to PMMH laboratory: www.pmmh.espci.fr/Contact-357
#### Next Seminars
Februray 13th: Stéphane Dorbolo (U. Liège)
February 20th: Michiko Shimokawa (U. Nara, Japan)
March 13th: Christophe Gissinger (LPENS)
March 20th: Cédric Beaume (U. Leeds)
Full list at www.pmmh.espci.fr/Seminaires
Examples include crushed and grinned brittle materials like solid bars, plates and shells, or cubes and spheroids, but also liquid drops and bubbles, exploding liquid shells, plastic debris in the ocean, and remnants cavemen. We present an original experiment journals.aps.org/prl/abstract....
A new conservation law with a maximal randomness principle provides unifying predictions. I will explain when this principle applies, and why the fragment size distribution is a power law p(d) d^{-β}, with exponent
β = D + a - π^(D/2)/2^D(D/2) ! a function of the dimension of the breaking object D.
Microscopic descriptions often overlook the question of the size distribution, and the uncontrolled use of conservation principles leads to notorious mistakes (see §11 in JFM 898, P1, 2020).
When it comes to understand how a cohesive object breaks-up, there are two types of temptations : either seek for detailed mechanisms (capillary instabilities for liquids, cracks propagation in brittle solids...), or rely on a general principle to infer the multiplicity of the fragment sizes.
The PMMH seminar on Friday 6 Feb at 11:00 will be given by Emmanuel Villermaux, of the Institut de Recherche sur les Phénomènes Hors-Équilibre (IRPHÉ), Marseille.
Fragmentation with, and without mechanism : Are principles enough ?
Abstract below. Zoom link upon request.
Flyer for the CISM advanced course on Bioinspired Fluid-Structure Interactions
List of invited lecturers
Check out the advanced course on Fluid-Structure Interaction of Bioinspired Systems at #CISM in Udine! https://cism.it/en/activities/courses/C2601/
Come to PMMH laboratory: www.pmmh.espci.fr/Contact-357
Next Seminars
February 6th : Emmanuel Villermaux (IRPHÉ)
Februray 13th: Stéphane Dorbolo (U. Liège)
February 20th: Michiko Shimokawa (U. Nara, Japan)
March 13th: Christophe Gissinger (LPENS)
Full list at www.pmmh.espci.fr/Seminaires.
Exploiting this complex torque response, we further show that embedding fin-decorated beams into pneumatic bending actuators induces a snap-through instability, resulting in rapid actuation and a hysteretic mechanical response. This behavior enables fast, programmable motion.
we introduce curvature-dependent mechanical hardening. When combined with the fins, this strategy enables the programming of highly tunable, and non-monotonic torque–curvature responses. An inverse design framework is developed to achieve on-demand torque profiles and is validated experimentally.
Fin buckling leads to an abrupt reduction of the beam's effective moment of inertia, giving rise to a non-monotonic moment–curvature relationship closely analogous to that observed in carpenter's tapes. By incorporating pillars that engage only beyond a prescribed curvature,
During bending, longitudinal stretching of the fins couples to the beam curvature, inducing transverse compression within the fins. Beyond a critical curvature, this compression triggers fin buckling, which we rationalize in terms of the governing geometric parameters.
Inspired by the nonlinear bending response of a carpenter's measuring tape and the pronounced drooping of U-shaped plant petioles under water stress, we investigate the bending behavior of rectangular beams decorated with one or more longitudinal vertical fins.
Recent advances in mesoscale material architecture have enabled the design of structures exhibiting nonclassical mechanical responses, including auxetic behavior, mode coupling (e.g., stretching–bending and stretching–twisting), and exceptional stiffness-to-weight ratios.
The PMMH seminar on Friday 30 Jan at 11:00 will be given by
Émilien Dilly,
Laboratoire Interdisciplinaire de Physique, Grenoble.
Title: Metabeams with programmable nonlinear bending response
Abstract below. Zoom link upon request.
Next seminars:
Jan 23: Glorieux (LKB)
Jan 30: Dilly (LiPhy)
Feb 6: Villermaux (IRPHÉ)
Feb 13: Dorbolo (Liège)
These studies aim to identify the role of key parameters—including fiber volume fraction, fiber aspect ratio, and fiber stiffness—on the mechanical behavior and flow properties of fiber-reinforced granular media.
We investigate the mixing and dispersion of fibers within the granular medium, the influence of fibers on the rheological response of the material measured in a vane geometry, and the impact of fiber reinforcement on granular avalanche dynamics.
