Papers by Stéphane Santucci
arXiv (Cornell University), May 17, 2019
<p>We propose a subcritical fracture growth model, coupled with the... more <p>We propose a subcritical fracture growth model, coupled with the elastic redistribution of the acting mechanical stress along rugous rupture fronts. We show the ability of this model to quantitatively reproduce the intermittent dynamics of cracks propagating along weak disordered interfaces [1]. We assume that the fracture energy of such interfaces (in the sense of a critical energy release rate) follows a spatially correlated normal distribution. We compare various statistical features from the obtained fracture dynamics to that from experimental cracks propagating in sintered polymethylmethacrylate (PMMA) interfaces. In previous works, it has been demonstrated that such approach could reproduce the mean advance of fractures and their local front velocity distribution. Here, we go further by showing that the proposed model also quantitatively accounts for the complex self-affine scaling morphology of crack fronts and their temporal evolution, for the spatial and temporal correlations of the local velocity fields and for the avalanches size distribution of the intermittent growth dynamics. We thus provide new evidence that Arrhenius-like subcritical growth laws are particularly suitable for the description of creeping cracks.</p><p>Reference:</p><p>[1] Vincent-Dospital, T., Cochard, A., Santucci, S., Måløy, K.J., Toussaint, R.,  Thermally activated intermittent dynamics of creeping crack fronts along disordered interfaces. <em>Sci Rep</em> <strong>11, </strong>20418 (2021). https://doi.org/10.1038/s41598-021-98556-x</p>
EGU General Assembly Conference Abstracts, Apr 1, 2017
EPJ Web of Conferences, 2021
We investigate experimentally the discharge of a 2D-silo, a Hele-Shaw cell, filled with a mono la... more We investigate experimentally the discharge of a 2D-silo, a Hele-Shaw cell, filled with a mono layer of ferromagnetic grains submitted to an external magnetic field B perpendicular to the cell plane. In this case the magnetic pair interactions are repulsive. We show that the granular flow rate decreases systematically with the amplitude of the external magnetic field applied. Interestingly, while the output flow rate remains constant during an experiment, we reveal very large spatio-temporal fluctuations of the packing density within the cell, particularly evident for magnetic field of high amplitudes.
Nature Communications, 2021
A pile of grains, even when at rest in a silo, can display fascinating properties. One of the mos... more A pile of grains, even when at rest in a silo, can display fascinating properties. One of the most celebrated is the Janssen effect, named after the pioneering engineer who explained the pressure saturation at the bottom of a container filled with corn. This surprising behavior arises because of frictional interactions between the grains through a disordered network of contacts, and the vessel lateral walls, which partially support the weight of the column, decreasing its apparent mass. Here, we demonstrate control over frictional interactions using ferromagnetic grains and an external magnetic field. We show that the anisotropic pairwise interactions between magnetized grains result in a radial force along the walls, whose amplitude and direction is fully determined by the applied magnetic field. Such magnetic Janssen effect allows for the fine tuning of the granular column apparent mass. Our findings pave the way towards the design of functional jammed materials in confined geomet...
By means of a new crack paths computation scheme, based on finite elements analysis and the use o... more By means of a new crack paths computation scheme, based on finite elements analysis and the use of the principle of local symmetry, we examine the possibility of a pair of parallel and offset cracks in a plate (known as EP-cracks) to repulse or attract one another as they propagate inward. The variations of the initial kink angle with the tip to tip separation distances get more abrupt as the inner tips get closer, demonstrating the acute influence of geometric parameters in the case of EP-cracks. This sensitivity is confirmed by the shape of whole crack paths : a seemingly small change of initial geometry can lead to a completely different final path. These results, when compared to experimental data, emphasize the limit of linear elastic fracture mechanics (LEFM) to compute the paths of interacting cracks. Mots clefs : LEFM, Finite Element Method, EP-cracks, Crack Interaction, PLS 23ème Congrès Français de Mécanique Lille, 28 au 1er Septembre 2017
Russian Journal of Physical Chemistry A, 2003
Slow crack growth in brittle elastic materials is modeled as a thermal activation process where s... more Slow crack growth in brittle elastic materials is modeled as a thermal activation process where stress fluctuations make it possible to overcome a breaking threshold through a series of irreversible steps. We study the case of a single crack in a flat sheet for which analytical predictions can be made and compare them with results from the equivalent problem of a 2D spring network.
a Institut de Physique du Globe de Strasbourg, CNRS, EOST-University of Strasbourg, 5 rue Descart... more a Institut de Physique du Globe de Strasbourg, CNRS, EOST-University of Strasbourg, 5 rue Descartes, 67084 Strasbourg Cedex, France. Fax: +33 3 68 85 01 25; Tel: +33 3 68 85 03 37; E-mail: renaud.toussaint@unistra.fr b Centre for Advanced Study at The Norwegian Academy of Science and Letters, Drammensveien 78, 0271 N-Oslo, Norway. c University of Lyon, ENS de Lyon, University Claude Bernard, CNRS, Laboratoire de Physique, F-69342 Lyon, France. d Department of Physics, University of Oslo, PB 1048 Blindern, NO-0316 Oslo, Norway. † Electronic Supplementary Information (ESI) available: [details of any supplementary information available should be included here]. See DOI: 10.1039/b000000x/ ∆T (x,y) = ∫ t
Scientific Reports, 2021
We present a subcritical fracture growth model, coupled with the elastic redistribution of the ac... more We present a subcritical fracture growth model, coupled with the elastic redistribution of the acting mechanical stress along rugous rupture fronts. We show the ability of this model to quantitatively reproduce the intermittent dynamics of cracks propagating along weak disordered interfaces. To this end, we assume that the fracture energy of such interfaces (in the sense of a critical energy release rate) follows a spatially correlated normal distribution. We compare various statistical features from the obtained fracture dynamics to that from cracks propagating in sintered polymethylmethacrylate (PMMA) interfaces. In previous works, it has been demonstrated that such an approach could reproduce the mean advance of fractures and their local front velocity distribution. Here, we go further by showing that the proposed model also quantitatively accounts for the complex self-affine scaling morphology of crack fronts and their temporal evolution, for the spatial and temporal correlation...
Nousétudions expérimentalement la dynamique de pelageà vitesse imposée d'un rouleau de ruban adhé... more Nousétudions expérimentalement la dynamique de pelageà vitesse imposée d'un rouleau de ruban adhésif, et en particulier son régime dit de stick-slip qui consiste en des oscillationsà haute fréquence entre des phases lentes et rapides du pelage. Grâceà l'analyse d'images de caméra rapide, nous mesurons les caractéristiques de l'instabilité (durée et amplitude) pendant ces phases lentes et rapides lors du régime de pelage stationnaire. Nous montrons que leurs dépendances avec la vitesse de pelage et la longueur de bande pelée sont radicalement différentes de celles présentées dans desétudes antérieures.
Nous avonsétudié lesémissions acoustiques résultant de la rupture sous-critique d'une feuille de ... more Nous avonsétudié lesémissions acoustiques résultant de la rupture sous-critique d'une feuille de papier. La fracture avance par des sauts discrets produisant desévènements acoustiques soudains et discrets. Le temps d'attente entre deuxévènements acoustiques et l'énergie desévènements sont distribués suivant des lois de puissance. La valeur de l'exposant de la loi de puissance pour la distribution desénergies dépend fortement de la fréquence de l'analyse. Cet effet est dû aux corrélations temporelles entre lesévènements et en particulierà l'existence de répliques.
While of paramount importance in material science, the dynamics of cracks still lacks a complete ... more While of paramount importance in material science, the dynamics of cracks still lacks a complete physical explanation. The transition from their slow creep behavior to a catastrophic propagation regime is a notable key, as it often leads to full material failure. We show how simple statistical physics, coupled with the dissipation of heat at the fracture front, can actually account for the entire dynamics in a unified framework. Such a model fits indeed the reported rupture of two different materials, for the first time over eight decades of propagation velocities. Thus, we explain how matter suddenly fails in a brittle manner, by inferring that cracks can reach thousands of Kelvins at their tips. Such extreme temperatures also elucidate the fractoluminescence phenomenon, the emission of visible light sometimes observed during rupture.
Physical Review Applied
We propose an original microbubble encapsulation process, using electrostatics as a driving force... more We propose an original microbubble encapsulation process, using electrostatics as a driving force to guide either particles or polymerizable precursors to the bubble surface. Taking advantage of attractive interactions between surfactant-laden charged bubbles and oppositely charged self-assembling species, our method produces capsules with diverse protective shells that remain stable for years. Considering heterogeneous electrostatic double-layer interactions, we quantitatively predict critical particle surface potentials required for complete encapsulation. The particle-based shells can be disintegrated with a pH adjustment, allowing for a controlled release of encapsulated payloads, while the glassy continuous silicate capsules are chemically resistant to pH changes. Our process, which can be equally applied to liquid droplets, easily scales up for industrial developments.
EGU General Assembly Conference Abstracts, Apr 1, 2019
EPJ Web of Conferences, 2021
We investigate both experimentally and theoretically the apparent mass of a ferromagnetic granula... more We investigate both experimentally and theoretically the apparent mass of a ferromagnetic granular assembly filling a cylindrical container and submitted to a magnetic fieldB, aligned vertically along the silo. We show that the mass of the ferromagnetic granular column depends strongly on the applied magnetic field. Notably, our measurements deviate strongly from the exponential saturation of the measured mass as a function of the true mass of the grain packing, as predicted by Janssen [H.A. Janssen, Vereins Eutscher Ingenieure Zeitschrift, 1045 (1895)]. In particular, the measured mass of tall columns decreases systematically as the amplitude of the magnetic field increases. We rationalize our experimental findings by considering the induced magnetic dipole-dipole interactions within the whole packing. We show the emergence of a global magnetic radial force along the walls of the silos, fully determined by the external magnetic field. The resulting tunable frictional interactions a...
We have performed an experimental study of the interaction of two collinear cracks in different p... more We have performed an experimental study of the interaction of two collinear cracks in different polymer sheets submitted to uniaxial stress at a constant imposed velocity. Depending on the samples geometry and the material used, we could observe that the two cracks interact in different ways. More specifically, we could observe different crack trajectories, with in particular, a repulsive regime, which evolves systematically with the initial vertical crack separation d. We show that the angle θ characterizing the amplitude of the repulsion and specifically its evolution with d depends strongly on the microscopic behavior of the material. We provide a physical interpretation of our results, based on the observation of different shape and size of the fracture process zone in the different samples studied. At interaction distances larger than the process zone size, the microscopic shape of the process zone tip controls the amplitude of the crack repulsion, contrary to the macroscopic m...
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Papers by Stéphane Santucci