Christophe Perge
École normale supérieure de Lyon
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Publication
Featured researches published by Christophe Perge.
Physical Review Letters | 2014
Mathieu Leocmach; Christophe Perge; Thibaut Divoux; Sébastien Manneville
Biomaterials such as protein or polysaccharide gels are known to behave qualitatively as soft solids and to rupture under an external load. Combining optical and ultrasonic imaging to shear rheology we show that the failure scenario of a protein gel is reminiscent of brittle solids: after a primary creep regime characterized by a power-law behavior whose exponent is fully accounted for by linear viscoelasticity, fractures nucleate and grow logarithmically perpendicularly to shear, up to the sudden rupture of the gel. A single equation accounting for those two successive processes nicely captures the full rheological response. The failure time follows a decreasing power law with the applied shear stress, similar to the Basquin law of fatigue for solids. These results are in excellent agreement with recent fiber-bundle models that include damage accumulation on elastic fibers and exemplify protein gels as model, brittlelike soft solids.
Journal of Rheology | 2014
Christophe Perge; Nicolas Taberlet; Thomas Gibaud; Sébastien Manneville
We report on the response of a yield stress material, namely, a colloidal gel made of attractive carbon black particles, submitted to large amplitude oscillatory shear stress (LAOStress) in a Couette geometry. At a constant stress amplitude well below its apparent yield stress, the gel displays fatigue and progressively turns from an elastic solid to a viscous fluid. The time-resolved analysis of the strain response, of the Fourier components, and of Lissajous plots allows one to define two different timescales τw<τf associated with the yielding and fluidization of the gel. Coupling rheology to ultrasonic imaging further leads to a local picture of the LAOStress response in which the gel first fails at the walls at τw and then undergoes a slow heterogeneous fluidization involving solid–fluid coexistence until the whole sample is fluid at τf. Spatial heterogeneities are observed in both the gradient and vorticity directions and suggest a fragmentation of the initially solidlike gel into macroscopic domains...
Physical Review E | 2014
Marc-Antoine Fardin; Christophe Perge; Nicolas Taberlet; Sébastien Manneville
The Taylor-Couette flow of a dilute micellar system known to generate shear-induced structures is investigated through simultaneous rheometry and ultrasonic imaging. We show that flow instabilities must be taken into account since both Reynolds and Weissenberg numbers may be large. Before nucleation of shear-induced structures, the flow can be inertially unstable, but once shear-induced structures are nucleated, the kinematics of the flow become chaotic, in a pattern reminiscent of the elastically dominated turbulence known in dilute polymer solutions. We outline a general framework for the interplay between flow instabilities and flow-induced structures.
European Physical Journal E | 2014
Christophe Perge; Marc-Antoine Fardin; Sébastien Manneville
Abstract.Complex fluids such as emulsions, colloidal gels, polymer or surfactant solutions are all characterized by the existence of a “microstructure” which may couple to an external flow on time scales that are easily probed in experiments. Such a coupling between flow and microstructure usually leads to instabilities under relatively weak shear flows that correspond to vanishingly small Reynolds numbers. Wormlike micellar surfactant solutions appear as model systems to study two examples of such instabilities, namely shear banding and elastic instabilities. Focusing on a semidilute sample we show that two-dimensional ultrafast ultrasonic imaging allows for a thorough investigation of unstable shear-banded micellar flows. In steady state, radial and azimuthal velocity components are recovered and unveil the original structure of the vortical flow within an elastically unstable high shear rate band. Furthermore thanks to an unprecedented frame rate of up to 20000fps, transients and fast dynamics can be resolved, which paves the way for a better understanding of elastic turbulence.Graphical abstract
Soft Matter | 2016
Thomas Gibaud; Christophe Perge; Stefan B. Lindström; Nicolas Taberlet; Sébastien Manneville
Fatigue refers to the changes in material properties caused by repeatedly applied loads. It has been widely studied for, e.g., construction materials, but much less has been done on soft materials. Here, we characterize the fatigue dynamics of a colloidal gel. Fatigue is induced by large amplitude oscillatory stress (LAOStress), and the local displacements of the gel are measured through high-frequency ultrasonic imaging. We show that fatigue eventually leads to rupture and fluidization. We evidence four successive steps associated with these dynamics: (i) the gel first remains solid, (ii) it then slides against the walls, (iii) the bulk of the sample becomes heterogeneous and displays solid-fluid coexistence, and (iv) it is finally fully fluidized. It is possible to homogeneously scale the duration of each step with respect to the stress oscillation amplitude σ0. The data are compatible with both exponential and power-law scalings with σ0, which hints at two possible interpretations of delayed yielding in terms of activated processes or of the Basquin law. Surprisingly, we find that the model parameters behave nonmonotonically as we change the oscillation frequency and/or the gel concentration.
Review of Scientific Instruments | 2013
Thomas Gallot; Christophe Perge; Vincent Grenard; Marc-Antoine Fardin; Nicolas Taberlet; Sébastien Manneville
Soft Matter | 2015
F. Martoïa; Christophe Perge; P. J. J. Dumont; L. Orgéas; Marc-Antoine Fardin; Sébastien Manneville; M. N. Belgacem
Soft Matter | 2014
Marc-Antoine Fardin; Christophe Perge; Nicolas Taberlet
Physical Review E | 2012
Christophe Perge; M. A. Aguirre; Paula A. Gago; Luis A. Pugnaloni; Denis Le Tourneau; Jean-Christophe Géminard
Soft Matter | 2014
Christophe Perge; Marc-Antoine Fardin; Sébastien Manneville