Critical state as an emerging property multiscale modeling of granular materials

  • Wautier, Antoine (INRAE)
  • Deng, Na (L3SR)
  • Liu, Zayong (USMB)
  • Nicot, François (USMB)

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The complex behavior of granular materials at macroscale stems from the coupling between the local physical interactions between grains and geometrical effects. In this sense, granular materials fall under the greater umbrella of complex systems (i.e. systems composed of a large number of elementary simple elements able to arrange in a variety of configurations) that are known to give rise to the myriad of emergent behaviors and parameters, fundamentally different from those at lower scales. With respect to constitutive modeling of granular plasticity, the concept of critical state (which emerge from the detailed balance of conformational transitions), stands as a cornerstone of constitutive theory for granular materials. Based on the extensive analysis of the rates of mesostructural transformations in DEM simulations, a deactivation/reactivation procedure acting on the local mesoscale is proposed to enrich a specific micromechanical-based constitutive model (the H-model). This procedure mimics the microstructure changes resulting from contact grain and loss that modifies the contact network with no volume change. We show how this procedure enable to make stationary regimes emerge naturally in multi-scale constitutive modeling without drawing from any empirical law at the macroscopic scale.