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Publication
Featured researches published by Elisabeth Bouchaud.
Journal of Physics: Condensed Matter | 1997
Elisabeth Bouchaud
Experiments concerning the morphology of fracture surfaces of various materials are reviewed. The observations are interpreted within the framework of models of lines moving in a random environment. This suggests that fracture of heterogeneous materials could be seen as a dynamic phase transition.
EPL | 1990
Elisabeth Bouchaud; G. Lapasset; J. Planès
Different rupture modes and different fracture toughness values were obtained on an aluminium alloy subjected to four different heat treatments. The correlation functions of the bidimensional cuts of the four fractured surfaces were determined. It was found that these surfaces were fractal, and that their fractal dimensions were identical, within experimental error.
Physical Review Letters | 2003
Fabrice Célarié; Silke Prades; Daniel Bonamy; L. Ferrero; Elisabeth Bouchaud; Claude Guillot; C. Marlière
We report in situ atomic force microscopy experiments which reveal the presence of nanoscale damage cavities ahead of a stress-corrosion crack tip in glass. Their presence might explain the departure from linear elasticity observed in the vicinity of a crack tip in glass. Such a ductile fracture mechanism, widely observed in the case of metallic materials at the micrometer scale, might be also at the origin of the striking similarity of the morphologies of fracture surfaces of glass and metallic alloys at different length scales.
Physical Review Letters | 1997
P. Daguier; B. Nghiem; Elisabeth Bouchaud; François Creuzet
The fatigue fracture surfaces of a metallic alloy and the stress corrosion fracture surfaces of a silicate glass are investigated as a function of crack velocity. It is shown that in both cases there are two self-affine fracture regimes. At large enough length scales, the universal roughness index {zeta}{approx_equal}0.78 is recovered. At smaller length scales, the roughness exponent is close to {zeta}{sub c}{approx_equal}0.50. The crossover length {xi}{sub c} separating these two regimes strongly depends on the material, and exhibits a power-law decrease with the measured crack velocity {xi}{sub c}{proportional_to}v{sup -{phi}}, with {phi}{approx_equal}1. The exponents {nu} and {beta} characterizing the dependence of {xi}{sub c} and v upon the pulling force are shown to be close to {nu}{approx_equal}2 and {beta}{approx_equal}2. {copyright} {ital 1997} {ital The American Physical Society}
Physical Review Letters | 2006
Laurent Ponson; Daniel Bonamy; Elisabeth Bouchaud
The self-affine properties of postmortem fracture surfaces in silica glass and aluminum alloy were investigated through the 2D height-height correlation function. They are observed to exhibit anisotropy. The roughness, dynamic, and growth exponents are determined and shown to be the same for the two materials, irrespective of the crack velocity. These exponents are conjectured to be universal.
Journal of The Mechanics and Physics of Solids | 2002
Elisabeth Bouchaud; J.-P. Bouchaud; D.S. Fisher; S. Ramanathan; James R. Rice
We review recent theoretical progress on the dynamics of brittle crack fronts and its relationship to the roughness of fracture surfaces. We discuss the possibility that the small scale roughness of cracks, which is characterized by a roughness exponent ≃0.5, could be caused by the generation, during local instabilities by depinning, of diffusively broadened corrugation waves, which have recently been observed to propagate elastically along moving crack fronts. We find that the theory agrees plausibly with the orders of magnitude observed. Various consequences and limitations, as well as alternative explanations, are discussed. We argue that another mechanism, possibly related to damage cavity coalescence, is needed to account for the observed large scale roughness of cracks that is characterized by a roughness exponent ≃0.8.
Physical Review Letters | 2006
Daniel Bonamy; Laurent Ponson; Silke Prades; Elisabeth Bouchaud; Claude Guillot
We investigate the scaling properties of postmortem fracture surfaces in silica glass and glassy ceramics. In both cases, the 2D height-height correlation function is found to obey Family-Viseck scaling properties, but with two sets of critical exponents, in particular, a roughness exponent zeta approximately 0.75 in homogeneous glass and zeta approximately 0.4 in glassy ceramics. The ranges of length scales over which these two scalings are observed are shown to be below and above the size of the process zone, respectively. A model derived from linear elastic fracture mechanics in the quasistatic approximation succeeds to reproduce the scaling exponents observed in glassy ceramics. The critical exponents observed in homogeneous glass are conjectured to reflect the damage screening occurring for length scales below the size of the process zone.
Physical Review E | 1996
P. Daguier; Stéphane Hénaux; Elisabeth Bouchaud; François Creuzet
The fracture surface of a Ti3Al-based alloy is studied using both an atomic force microscope and a standard scanning electron microscope. Results are shown to be quantitatively comparable. Two fracture regimes are observed. It is shown in particular that the roughness index characterizing the small lengthscales regime is equal to 0.5. Furthermore, the large lengthscales fractal domain is found to spread over nearly six decades of lengthscales.
International Journal of Fracture | 2002
Stéphane Morel; Elisabeth Bouchaud; Jean Schmittbuhl; G. Valentin
We investigate the idea that the fractal geometry of fracture surfaces in quasibrittle materials such as concrete, rock, wood and various composites can be linked to the toughening mechanisms. Recently, the complete scaling analysis of fracture surfaces in quasibrittle materials has shown the anisotropy of the crack developments in longitudinal and transverse directions. The anomalous scaling law needed to describe accurately these particular crack developments emphasizes the insufficiency of the fractal dimension, usually used to characterize the morphology of fracture surfaces. It is shown that a fracture surface initiating from a straight notch, exhibits a first region where the amplitude of roughness increases as a function of the distance to the notch, and a second one where the roughness saturates at a value depending on the specimen size. Such a morphology is shown to be related to an R-curve behavior in the zone where the roughness develops. The post R-curve regime, associated with the saturation of the roughness, is characterized by a propagation at constant fracture resistance. Moreover, we show that the main consequence of this connection between anomalous roughening at the microscale and fracture characteristics at the macroscale is a material-dependent scaling law relative to the critical energy release rate. These results are confirmed by fracture experiments in Wood (Spruce and Pine).
EPL | 2008
Elisabeth Bouchaud; D. Boivin; J.-L. Pouchou; Daniel Bonamy; B. Poon; G. Ravichandran
The fracture surfaces of a Zr-based bulk metallic glass exhibit exotic multi-affine isotropic scaling properties. The study of the mismatch between the two facing fracture surfaces as a function of their distance shows that fracture occurs mostly through the growth and coalescence of damage cavities. The fractal nature of these damage cavities is shown to control the roughness of the fracture surfaces.