Ahmad AWDI, doctorant au sein des équipes Rhéophysique et multi-echelle, soutiendra sa thèse « Rheology and microstructure of unsaturated wet granular materials » le lundi 16 décembre à 14h00 dans l’amphithéâtre Cauchy de l’Ecole Nationale des Ponts et Chaussées (ENPC).

Le jury sera composé de:

• Rapporteur : Thierry RUIZ, Professeur Université de Montpellier
• Rapporteur : Patrick RICHARD, Directeur de Recherche MTE
• Examinatrice : Stéphanie DEBOEUF, Chargée de Recherche CNRS
• Examinateur : Guillaume OVARLEZ, Directeur de recherche CNRS
• Examinateur : Edward ANDÒ, Principal Scientist EPFL
• Examinateur : Olivier POULIQUEN, Directeur de recherche CNRS
• Encadrante : Camille CHATEAU, Chargée de Recherche ENPC
• Encadrant : Abdoulaye FALL, Chargé de Recherche CNRS
• Directeur de thèse : Jean-Noël ROUX, IPEF

Pour participer à la réunion Zoom, veuillez trouver ci-dessous les informations de la réunion :

https://univ-eiffel.zoom.us/j/82826464624?pwd=BPTxCtZPCZXuePbwaRQlTCtGvySajM.1

ID de réunion : 828 2646 4624

Mot de passe : By7WKJ0q

Résumé de la these

We report on experiments and discrete element simulations of homogeneous, simple, normal stress-controlled shear flows of model unsaturated wet granular materials: assemblies of frictional spherical particles bonded by a small quantity of a wetting liquid.  Firstly, the rheology of such unsaturated granular materials in the dense flow regime is characterized in terms of internal friction coefficient $\mu^*$ and solid fraction $\phi_S$, depending on the reduced pressure $P^*$ comparing capillary forces to controlled normal stress and on a \emph{visco-inertial number} $J$, combining the viscous number $I_v$ with inertial number $I$ as $J = I_v + 2I^2$. Secondly, the microstructure of such materials is explored using X-ray micro-tomography. Advanced segmentation techniques are employed to overcome challenges in distinguishing phases within the material, utilizing a combination of Random Forest and U-Net models for accurate segmentation of the X-ray images. This methodology enables the quantification of the solid and liquid fractions within the sample, revealing the effects of shear deformation on their distribution. Additionally, a new automated tool is developed for classifying different liquid morphologies within the liquid phase. The study demonstrates the impact of shear deformation on the redistribution and clustering of liquid morphologies. Moreover, the coordination number is estimated, providing detailed insights into the interactions between solid particles and liquid phases.  This work provides a robust methodology for volume characterization and quantitative analysis of complex wet granular material microstructures.