Physics based multi-scale constitutive modeling of granular materials

Abstract: 

Granular materials are complex in the sense that their constitutive behavior stems from the coupling between the local physical interactions between grains and geometrical effects. Grains self-organize into meso-scale structures, whose topology significantly influences macroscopic behavior, particularly failure modes. In addition, the microstructure of granular materials can evolve significantly over time with small grains being moved and removed by internal seepage flow, grains may break, contact laws may be modified by cementation/dissolution processes, freezing/thawing or change in water content.

Accounting for such changes in the microstructure is quite challenging with continuum scale constitutive modeling. The change of scale in granular materials implies to switch from a discrete to a continuum modeling framework. In the homogenization process new properties emerge from collective effects but at the same time a great quantity of information related to microstructure geometry is lost.

By combining discrete element simulations (DEM), and multi-scale constitutive modeling it is possible to explore the relationship between elementary physics of granular materials and their macroscopic response. In this presentation I illustrate i) how we can define appropriated meso-structures of a few grains to understand the local physics responsible for the emerging properties in granular materials, and ii) how we can include this knowledge to develop multi-scale constitutive models with the minimal microstructure ingredients to reflect the complex mechanical behavior of granular material. Starting from the particular H-model, I will show how such a modeling strategy can be used to make critical state to emerge at the continuum level. I will also show how the failure modes of granular material (and in particular the sensitivity to static liquefaction) can be controlled through small changes in the topology of meso-structures (infiltration and clogging of fine grains). 

‼️ Le séminaire peut être suivi en ligne via le lien : https://univ-amu-fr.zoom.us/j/95011527683?pwd=bTeNvaaZY75buaa7bRL0pcucXSASm7.1

Le mardi 6 octobre 2026 à 11h00 / Amphithéâtre François Canac, LMA

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