A combined experimental-numerical study of the compaction behavior of NaCl

The compaction behavior of NaCl as a model substance is investigated by an integrated experimental and computational approach. The method for characterization of this granular material employs convenient experiments: load-displacement measurements of compaction; measurements of strain on outer circumference of an elastic tubular die; load on bottom and top of the powder compact, as well as compressive strength tests. Related equations for identification of material parameters are derived and are used to characterize powder behavior and powder-die friction. Subsequently, these material parameters are used in simulations with the Drucker-Prager-Cap (DPC) model. For the verification of the computations density distributions are determined based on micro X-ray computer tomography. Good agreement between the spatial density distributions from measurements and simulations is obtained. Restrictions of computer tomography in powder compaction applications are specified. While the study employs NaCl as a model substance, the approach is applicable to a wider array of granular substances.