A theoretical model for compaction of granular materials

A theoretical model is developed for the description of the compaction of granular materials exemplified by granulated ceramic powders. Its predictions compare satisfactorily to results of uniaxial compaction tests of ceramic granules of lead magnesium niobate-lead titanate (PMN-PT), rutile, and spray-dried alumina, The theory uses volume-based statistical mechanics and an activation analogy to treat, in parallel, the rearrangement of granules and their deformation, Variation of the model incorporates a distribution of barriers to deformation, which can be considered to include the effects of statistical pressure distributions within the compact, Other curve-fitting schemes available in the literature are shown to correspond to particular cases of the theory, and a justification of the equations used in those schemes is provided on physical grounds.