Postdoctoral associate Université de Montpellier Educ ation

Postdoctoral associate
Université de Montpellier
detailed CV
Laboratoire de Mécanique et Génie Civil
13/Jan/1986 in Nîmes (France)
[email protected]
+33 7 84 08 10 45
Education
435 rue du Chateau, apt. 204
Grabels, 34790, France
PhD in Physics from École Polytechnique [EP, Palaiseau, France]: 10/2010-10/2013
Master degree in Mechanical Engineering from Pennsylvania State University
[PSU, State College, USA] (grade A+): 09/2008-12/2009
Degree in engineering from École Centrale de Lyon [ECL, Écully, France] (ranked top 5 %):
10/2006-06/2008
Master degree in science, from ECL : 10/2006-06/2008
Postdoctoral research at LMGC [Université de Montpellier, Montpellier, France] 12/2015-present
subject: Local monitoring of root growth in granular medium (cf. Annexe A)
PhD research at Commissariat à l'Énergie Atomique [CEA, Saclay, France]: 10/2010-10/2013
subject: Statistical aspects of crack dynamics in inhomogeneous brittle materials.
Interdisciplinary work combining experimental and numerical aspects at the interface between
nonlinear/statistical physics and solids mechanics (cf. Annexe C)
Visiting student at the Massachusetts Institute of Technology [MIT, Cambridge, USA] 04-05/2013
subject: Tayloring crack path toward toughening (cf. Annexe D)
Internship at CEA: 02-09/2010
subject: Numerical model for thermal fatigue simulation (cf. Annexe E)
US master research at PSU: 06-12/2009
subject: Perturbation analysis and polynomial chaos study of a periodic structure (cf. Annexe F)
Teaching assistant and lecturer at École Polytechnique Féminine [EPF, Sceaux, France]
02/2010-12/2012 (~60 h/y)
courses: Continuum mechanics, Finite elements for mechanics (cf. book)
Teaching assistant at PSU: 09/2008-09/2009
courses: Vibration in mechanics, Finite elements for mechanics
PhD students: D. Wang, A. Abed-Zadeh, Y. Zhao and Y. Zhao [Duke] 01/2014-present
Alberto Rosso (CNRS-LPTMS)
Bob Behringer (Duke)
Bulbul Chakraborty (Brandeis)
Corey O'Hern (Yale)
Daniel Bonamy (CEA-SPEC)
Dengming Wang (Lanzhou)
Joshua Dijksman (Wageningen)
References:
Undergrad students: X. Wu, X. Chen, Y. Xu, M. Lim, Z. Shang and M. Cox [Duke]
Collaborations:
Mentoring Teaching
Experiences:
Research
Postdoctoral research at Duke University [Duke, Durham, USA] 11/2013-11/2015
subject: Static and flow properties of the 2D and 3D granular materials near the jamming
transition (cf. Annexe B)
01/2014-02/2015
D. Bonamy (CEA): [email protected]
R.P. Behringer (Duke): [email protected]
P.M. Reis (MIT): [email protected]
A. Rosso (CNRS-LPTMS): [email protected]
D. Dalmas (CNRS-ECL): [email protected]
Skills
Research skills:
Numerical simulations in fracture
Experiments in fracture mechanics
Experiments on granular media
Polymer sintering process
Photo-elastic technics
Computational languages:
Unix/Windows
Python
Octave/MatLab
LabView
Cast3m
Arduino IDE
C++
Past and present research themes:
Fracture of brittle materials
Statistical physics of fracture and sheared grains
Crackling/earthquake/avalanche statistics
Jamming transition
Thermal fatigue
Complex systems
Granular flows
Root growth
J.Barés, D.Bonamy, A. Rosso Statistical study of the random toughness continuum mechanics
pinning model (under finalization)
Peer reviewed publications
J.Barés, L.Hattali, D.Bonamy, D.Dalmas, Fore-shock main-shock after-shock sequence in
nominaly brittle fracture (under finalization)
J.Barés, D.Wang, T.Bertrand, C.O'Hern, R.Behringer, Yield transition in a 2D sheared amorphous solid: from local to global avalanches (submitted to Physical Review E, )
M.Cox, D.Wang, J.Barés, R.Behringer, Self-organized magnetic particles to tune the mechanical behaviour of a granular system (submitted to Physical Review Letters, arXiv:1511.02219)
Y.Zhao, J.Barés, et al., Packings of 3D stars: Stability and structure (accepted by Granular
Matter, arXiv:1511.06026)
M.Lim, J.Barés, R.Behringer, Forces and Flows in Non-Newtonian Suspensions (accepted by
Physical Review Letters)
T. Cambonie, J.Barés et al., Effect of the porosity on the fracture surface roughness of sintered materials: From anisotropic to isotropic self-affine scaling, Physical Review E, 91, Jan. 2015
J.Barés, L.Hattali, D.Bonamy, D.Dalmas, Fluctuations of global energy release and crackling
in nominally brittle heterogeneous fracture, Physical Review Letters, 113, Dec. 2014.
J. Barés, D. Bonamy et al., Nominally brittle cracks in inhomogeneous solids: From
microstructural disorder to continuum-level scale, Frontiers in Physics, 2014, 2
J.Barés, D.Bonamy, L.Barbier, Crackling vs. continuum-like dynamics in brittle failure,Physical
Review Letters, 111, Aug. 2013.
J.Barés, L.Gelebart, L.Vincent, A joined finite element based method to simulate 3D crack
network initiation and propagation in mechanical and thermal fatigue, International Journal
of Fatigue, 44, Nov. 2012.
Book
N.Recho and J.Barés, Une introduction à la méthodes des éléments finis en mécanique,
édition Ellipse, collection Technosup, ISBN : 9782340004009.
Conferences
L.Hattali, J.Barés, D.Bonamy, L.Ponson, Low Velocity Surface Fracture Patterns in Brittle
Material: A Newly Evidenced Mechanical Instability, Materials science forum, 706-709,
Jan. 2012.
Marsh meeting, Baltimore MD 03/2016 (invited talk)
DFD meeting, Boston MA 11/2015 (oral)
EMI, Standford, CA 06/2015 (invited talk)
Marsh meeting, San Antonio TX 03/2015 (oral, chairman)
DFD meeting, San Francisco CA 11/2014 (oral)
SES conference, Perdue University IN 10/2014 (oral)
Gordon Seminars, Stonehill College MA 08/2014 (invited talk)
Gordon Conference, Stonehill College MA 08/2014 (poster)
Marsh meeting, Denver CO 03/2014 (oral)
International conference on fracture, Beijing 06/2013 (oral)
Materials deformation: fluctuations, scaling, predictability, Les Houches 02/2013 (oral)
Conferences
Seminars
Outreach
Journées de la matiére condensée, Montpellier 08/2012 (oral)
Fracture phenomena in nature and technology, IUTAM symposium, Brescia 07/2012 (poster)
Journées de la physique statistique, Paris 02/2012 (oral)
Materials deformation: fluctuations, scaling, predictability, Les Houches 01/2012 (poster)
Micro-DICE: ice deformation, Grenoble, 11/2011 (oral)
Congrés Français de la mécanique, Besançon, 09/2011 (oral)
Wageningen University, Pays-Bas 01/2015
Duke University, Durham NC 10/2014
Laboratoire Mécanique Génie Civil, Montpellier 04/2014
Laboratoire Charles Coulomb, Montpellier 04/2014
Ecole Normale Superieure, Lyon 03/2014
Ecole Centrale, Lyon 03/2014
St Gobain, Cavaillon 11/2013
St Gobain, Aubervilliers 10/2013
CEA Service Physique Etat Condensé, Saclay 09/2013
"Ruptures: les matériaux roulent des mécaniques" Palais de la découverte, Paris:
scientific exposition on the diversity of material reactions when loaded: deformation,
flowing, fracture... http://www.palais-decouverte.fr/index.php?id=ruptures2013
"La sience en marche" CEA Saclay: French Science Learning Centres which permits to high
school teachers to be aware of what is currently happening in science research.
Awards
http://www.cea.fr/jeunes/espace-enseignants/la-science-en-marche
Prix de thèse du Triangle de la Physique, 11/2015
London Fritz postdoctoral fellowship, 09/2014
Best oral presentation award at the International conference on fracture, 06/2013
Annexe A
Postdoctoral research at LMGC Montpellier
My current post-doc research projects concern the coupling between the biological physics of root growth
and the physics of granular materials. More specifically I study the interaction between the growth of a
root network in a 2D granular material and the development of the induced heterogeneous force network
in the granular medium. The goal is to learn more about how a root chooses a path in a soil knowing the
stress it undergoes. It would permit to improve technics of soil stabilization and plant growth.
To tackle those problems, I grow chickpeas in a 2D vertical bed of photo-elastic discs varying the space
between the particles and slowly shearing the granular system. Evolution of the root network, of the grain
positions and stress inside the system is monitored during the growth.
Annexe B
Postdoctoral research at Duke
11/2013, 2 years
My first post-doc research projects concern the physics of granular materials. Those materials are
surprizing because on a large scale they can behave like a solid (walking on wet sand on a beach), a
liquid (flowing sand between fingers), or a gaz (sandstorm in a desert). Hence, open questions are how
transitions occur between these states, how collective behaviors may arise and what forms they take,
what are the relevant properties of the grains (shape, friction, stiffness), etc. My work focus on the
fundamental behavior of near-jamming granular systems, with a particular interest on the effect of shear
and friction. To tackle those problems, I use mainly both a 2D and 3D experimental approach.
The first, which consists in a 2D Couette-like experiment permits to apply shear strain on photo-elastic
grains without inducing shear bands. This allows to determine the dynamical properties (positions and
force chains) for sheared systems of grains below the isotropic jamming.
The second one is a 3D laser scan which tracks the grain positions and force chains when applying any
load on a granular system. This allows to determine the dynamic of shearing for each 3D shear mode.
PhD research at CEA Saclay (IRAMIS)
Annexe C
12/2015
10/2010, 3 years
My PhD was done at the CEA under the supervision of D. Bonamy and in collaboration with D. Dalmas
(UMR CNRS/St-Gobain). My research work focussed on the solid fracture of heterogneous materials. This
problem is classically addressed within the framework of continuum mechanics. Still, stress enhancement
at crack tips makes the failure behavior observed at continuum-level scale extremely dependent on
microstrcuture inhomogeneities down to very small scales. This yields statistical aspects, which, by
essence, cannot be addressed by conventional engineering continuum tools. I reached this problem from
three different points of view.
First, I designed an original model experiment which propagates a crack within an artificial rock of tunable
microstructure (sintered polymer beads of modulated diameters). The loading speed is tunable over a
wide range. The crack dynamics, and the evolution of mechanical energy, of its release rate, and of
fracture energy can be monitored in real time. In parallel, the crack "seismicity" is probed and localized
via a series of acoustic transducers. The experiments characterize quantitatively the crackling dynamics
of cracks, also they evidence intriguing statistical similarities between the seismicity associated with this
simple situation of single crack propagation under tension and that observed in the much more complex
situation of multicracking in compressive fracture experiments and in earthquakes.
In parallel, I addressed the problem numerically. The simulations invoke a recent stochastic model
obtained by mapping heterogeneous fracture with a depinning transition of elastic manifolds in random
potentials. This allowed me to unravel when (i.e. which loading conditions, microstructure material
parameters, material constants...) continuum approaches are relevant and when crackling is observed.
More recently, I sought to better understand the role of damage, i.e. small microcracks localized in the
vicinity of the propagating crack tip, on the selection of the crackling dynamics. This was achieved via
lattice models of increasing complexity, from random fuse network mapping elasticity to scalar electric
problem, to finite element join model much capturing the tensorial aspects of elasticity.
Annexe D
Stay at EGS-lab, MIT
As part of a project funded by the MISTI MIT-France program, I spent one month at MIT working with Pr.
P.M. Reis. The research objective is to predictively understand how resistance to failure can be modulated
by forcing a crack to propagate along a path of imposed geometry. I developped an original experiment in
this context. Wedge-splitting geometry was used to break Plexiglas samples while the crack was guided
by decreasing locally the fracture toughness along a prescribed path. In the same time, finite elements
simulations (Cast3m software) were developed to study dynamic stability and to measure mechanical
fracture parameters for any crack path. This short project has demonstrated the feasability of such an
experiment, which is currently further developped. The final achievement of this project is expected to
inform various fields, from cutting edge technology to surgery. It may also provide a mechanical
explanation for some of the complex hierarchical fractal-like suture patterns observed in bones or seashells.
Annexe E
Master internship at CEA Saclay (SRMA)
06/2009, 6 months
This work was done at SRMA, CEA Saclay for my final master internship, under the supervision of L.
Gelebart and L. Vincent. The goal was to reproduce numerically experimental observations reported for
the thermal fatigue damage in steel. This issue is of high interest for the cooling vessels in nuclear power
plants. The model I developed consists in breaking joint elements (by vanishing their stiffness) in a 3D
periodic network of joined bulk finite elements (Cast3m software). By breaking the elements step by step,
it is possible to take into account initiation and further propagation of cracks due to cyclic thermal
loading. The parameters of the initiation and propagation laws were fitted from mechanical and thermal
fatigue experiments. The resulting simulations permit us to follow the crack initiation and propagation in
the material bulk. They were found to be in agreement with experiments. (see publication for more
details)
Master thesis at PSU
Annexe F
04/2013, 1 month
02/2010, 7 months
This work was done at PSU during my master thesis under the supervision of Dr. A. Sinha. Using
polynomial chaos technique, I analyzed the modal characteristics of an assembly of mistuned bladed
disks which is of high interest in the aeronautic field. More precisely, I computed the mean value and
standard deviation of eigenvalues and eigenvectors in such a system. This analysis only considers one
vibration mode for each of the N blades and the mistuning phenomenon was simulated by identifying the
modal stiffness of each blade with a stochastic variable. The results were compared with Monte Carlo
simulations and a Taylor series expansion showing a good agreement and a shorter computation time.
(see publication for more details)