Persistence of granular structure during compaction processes

Abstract

Compaction of granulated powder is a common forming process used in the ceramics industry. Glass spheres were used as a model system to investigate granule failure during die compaction. Stresses within an assembly of spheres follow a network of pathways. Results demonstrate the statistical nature of granule failure during compaction, with some granules failing at very low applied pressures while a large fraction persist at even the highest applied loads. At high compaction pressures, size distributions of compacted spheres were seen to approach the Dinger-Funk distribution for maximum packing. In the limiting case of maximum density, the Dinger-Funk equation predicts 33% of the volume of granules will have sizes in the range of the initial size distribution.