- Surface du Verre et Interfaces, joint research team Saint-Gobain - CNRS
joel.marthelot A_T espci.fr
jmarthel A_T mit.edu
I am a post-doc in Pedro Reis Egslab group at MIT since August 2014. I used to be a PhD student working with José Bico and Benoît Roman (PMMH, ESPCI), Jérémie Teisseire, Davy Dalmas and Etienne Barthel (SVI, SGR) on mechanical stability of thin films. I was a Raman-Charpak fellow (2014) in N. Menon lab (TIFR, TCIS, Hyderabad, India), a visiting student in Francisco Melo’s lab at USACH (2012), in Pedro Reis Egslab group at MIT (2010) and in Schlumberger research center in Tokyo (2008).
Cooperation fracture-delamination : spiral and croissant cracks paths in thin films
Thin film are widely used to functionalize surfaces. During the deposition process, the film usually build residual stresses that could cause the failure of the film by fracture or delamination. We study a new way of crack propagation where delamination and fracture cooperate leading to the failure of films usually considered as stable. The robusteness of the crescent and spirals patterns offer new opportunities to use cracks as a tool to pattern surfaces at small scales.
See also movies of fracture in real time of a crescent alley, a spiral or a competition between a duo of cracks and a following crack.
Self-replicating cracks: A collaborative fracture mode in thin films Phys. Rev. Lett 113, 085502. Published online 20 August 2014
See also press release in Le Monde by David Larousserie, Physics Today by Sung Chang, New Scientist by Jacob Aron (and the corresponding movie), in Inside Science by Gabriel Popkin and (in French) by ESPCI ParisTech, SVI, CNRS (Institut de physique and Institut des sciences de l’ingénierie et des systèmes) by Jean-Michel Courty, (INSIS CNRS), UPMC, (in German) in Welt der Physik by David Vogel.
The article is featured by Sarah Zhang on Gizmodo, by Douglas Natelson (Rice University) on his condensed matter blog, on physics4me, Auracaria de Chile, in Thai, in Tamil, on social networks by Physics Today on FB and (in Russian) by Образовач on VK
A new failure mechanism in thin film by collaborative fracture and delamination: interacting duos of cracks long paper focusing on duos of crack on arXiv
Relaxation of an elastic filament on a viscous interface
What is the shape of an elastic filament floating on a fluid interface? We observe the time-dependent relaxation of a bent filament reopening towards its straight, stress-free, configuration. We study a regime in which the dynamics are overdamped, but with the rod initially bent into a geometrically nonlinear regime. The dynamics of reopening are governed by a competition between the viscous drag of the liquid and the bending elastic force of the rod. We study the relaxation of shape as a function of the length, diameter and elasticity of the rod, and the viscosity of the fluid interface. This simple system could provide an easy method to characterize interfacial properties of fluid interfaces.
Thin film stability on flexible substrate : fracture
Mechanics of stiff coating film deposited on soft plastic substrates have recently gain interest due to the development of stretchable electronics application. When submitted to tensile stress, such films tend to fail with the apparition of arrays of parallel channel cracks transverse to the direction of deformation, with fatal consequenses for electrical conductivity. We study the propagation of such fractures in oxyde monolayers coated on a polymer substrate under uniaxial stretching. We show how the crack density undergoes a transition from a statistic failure distribution of brittle material to a deterministic failure set by the elastic mismatch between the film and the substrate and the substrate ductility.
Thin film stability on flexible substrate : wrinkling and buckling
The mismatch of Poisson ratio between the layer and the substrate lead to compressive strain in the transverse direction. For increasing applied strain, we observe undulations, wrinkles and delamination blisters. We study the interface strengthening by plastic dissipation in multilayer sandwich silver layer.
Janssen effect and gravity driven discharge in a soft silo
with Thomas Cambau and Jérémy Hure
In 1895, Janssen quantified the saturation of the bottom pressure in a granular material contained in a vertical container. He defined a typical pressure saturation length, accounting for friction of the grains on the container’s wall. The practical interest in avoiding the damage and collapse of silos has motivated numerous studies. In those studies, stresses were inferred from the measurement of the apparent mass at the bottom of the column. We directly obtained the stress field all along the collumn by measuring the displacement field of a soft elastomer silo containing a granular collumn. We confirmed the validity of Janssen’s description and determine the stress field during the gravity driven discharge of a silo through an aperture.
with Pedro M. Reis
We observe and charaterize the pattern of coils and tangles that a cable form when deployed onto a rigid surface.
Low Reynolds locomotion
The deformation of thin rods in a viscous liquid is important to understand the mechanics of motility in cells. We study experimentally a long macroscopic elastic filament rotating in a viscous fluid. As the rotation frequency increases, the filament undergoes a sharp transition, from a straight state to a helical shape, tightly wrapped around the rotation axis. This transition results from a competition between viscous stresses and elastic forces. The helicity generates a strong propulsive force along the axis of rotation. From a design perspective, the self-induced helicity of an elastic flagellum could be an efficient strategy to drive artificial swimmers.
Fracture on flexible substrate: an elasto-plastic model
J. Marthelot, J. Bico, J. Teisseire, D. Dalmas and B. Roman, in preparation
A new failure mechanism in thin film by collaborative
fracture and delamination: interacting duos of cracks (pdf)
J. Marthelot, J. Bico, F. Melo and B. Roman, submitted to JMPS
Self-replicating cracks: A collaborative fracture mode in thin films (pdf)
J. Marthelot, B. Roman, J. Bico, J. Teisseire, D. Dalmas and F. Melo, Phys. Rev. Lett 113, 085502, 2014
Local stresses in the Janssen granular column (pdf)
T. Cambau, J.Hure, and J. Marthelot, Phys. Rev. E, 88, 022204, 2013
Rotational dynamics of a soft filament : wrapping transition and propulsive forces (pdf)
N. Coq, O. du Roure, J. Marthelot, D. Bartolo and M. Fermigier, Phys. Fluids., 20, 051703, 2008.
Rupture et délamination de films minces (en français) (pdf)
Thèse de doctorat de l’Université Pierre et Marie Curie, soutenue le 18 juin 2014.
Evaluation of local stresses in the Janssen granular column
SWGM 2012, Puerto Varas, Chile, December 2012
Thin film mechanics on flexible substrate
ICF 13, Beijing, China, June 2013
Saint-Gobain High-Performance, Northboro, MA, March 2012
Exotic cracks in thin films
ILM Seminar, Universite Lyon 1, Lyon, July 2014
TCIS Seminar, TIFR, Hyderabad, April 2014
Journées scientifiques 2013, ESPCI, Paris, November 2013
CFM13, Bordeaux, August 2013
ICF 13, Beijing, China, June 2013
JMC13, Montpellier, August 2012
Réunion générale MePhy, Agay, June 2012
APS, March Meeting, Boston, MA, March 2012
Critère de rupture, GDR Phenix / MePhy, ESPCI, November 2011
On the propulsive efficiency of rotating elastica
APS, 60th Annual Meeting of the Divison of Fluid Dynamics, Salt Lake City, UT, November 2007
Materials Deformation (II) : Fluctuations, Scaling, Predictability, Les Houches, February 2013.
Modern Perspectives on Thin Sheets : Geometry, Elasticity, and Statistical Physics, Lorentz Center, Leiden, September 2012.
Materials Deformation (I) : Fluctuations, Scaling, Predictability, Les Houches, February 2012
"Un chercheur, une manip" with Benoît Roman, Camille Duprat, Pascal Raux, Pierre-Brice Bintein, Suomi Ponce, Palais de la découverte, March-April 2013
"Fracture de films minces" with Benoît Roman, Fête de la science, PMMH, November 2012, November 2013
"Poils mouillés et Origami capillaire" with José Bico, Espace des sciences Pierre-Gilles de Gennes, May 2012