Crunchy matter: The role of fabric evolution on the constrained compaction of a brittle porous medium.

摘要

This thesis documents experimental studies carried out to examine the compaction behavior of a brittle porous medium composed of a pack of highly collapsible porous grains. Three experimental series are documented. The first centers on characterizing the evolution of the fabric as the material is compacted in a short die under a constant deformation rate v. The results reveal a characteristic rate v* beyond which breakage contributes significantly to compaction. The second series of experiments reveals two extreme compaction regimes, defined by two different patterns of compaction observed experimentally for packs confined in tall dies, which promote localization due to sidewall friction. The rate v* renders a phase transition between such regimes; one that exhibits the periodic propagation of localized compaction bands, as observed via digital image correlation analyses. The third series enables examining the role that boundary conditions and material properties play in the characteristics of the compaction responses and patterns observed.