A Process-Based Pore Network Model Construction for Granular Packings Under Large Plastic Deformations

Abstract

We propose a process-based method for constructing a pore network model of granular packings under large deformations. The method uses the radical Voronoi tessellation and constructive solid geometry (CSG) operations on meshes of deformed particles, to construct a threedimensional solid of the pore network and estimate its geometric characteristics, CTS-model parameters and flow transport properties, and it uses the particle mechanics approach to model consolidation of powders under large deformations. This process-based method thus explicitly simulates not only a packing of grains but also its corresponding consolidation process, which in this work is restricted to powder die compaction up to a relative density close to one (i.e., to die filling, compaction to low porosity, unloading, and ejection). The efficacy of the proposed method is borne out by studying granular packings with the same composition, namely a 50-50 binary mixture of two monodisperse systems comprised by elasto-plastic spheres with bonding strength, but with microstructures which are topologically different, namely a random packing, a bilayer, and core-shell structures. These simulations reveal that topological differences affect the formation and evolution of the pore space statistical signature during consolidation and, therefore, showcase that process-based approaches for constructing PNM are of paramount relevance to understanding architectured granular material systems.