Compaction properties of dry granulated powders based on Drucker–Prager Cap model

Abstract

Dry granulation by roll compaction is a process of size enlargement used to produce granules with a good flowability for further die compaction process. To gain in the understanding of how granulated powders behave during die compaction and why they exhibit different behaviors different from those showed by the feed powder, the main material parameters proposed in Drucker-Prager Cap (DPC) model, were determined for MCC101 powder and two granule sizes obtained from roll-compacted ribbons. For that, the standard procedure calibration of DPC was used. Results showed that all the material properties are density-dependent and the properties of feed powder are higher than those of granulated powder. Moreover, the yield hardening function showed a decrease with the increase of the granule size, which highlighted that the granules of MCC 101 exhibit a softer work hardening than feed powders. Overall, the granules have smaller yield surface than the feed powder. Particularly, it was found, for both granule sizes and the MCC 101 powder, an overlapping of shear failure line at high relative density. Nevertheless, at low density, the cohesion was affected by the roll compaction of MCC 101, but no variation was observed for the internal friction angle. The obtained results are in agreement with the literature, where the granules were prepared from mini-tablets rather than from roll-compaction. However, some discrepancies were highlighted.

Thermally Activated Jamming in Ultrasonic Powder Compaction

“…Because the individual Cu particles were nanoporous, with a relative density that decreased from 0.96 to ≈0.80 over the course of the consolidation experiment, the packing fraction at which jamming sets on in Figure 6 is in the range 0.62–0.78. It is interesting to note that the form of the geometric hardening curve for the Cu powder near the jamming transition closely resembles the strengthening behavior observed in previous work on jamming of a fluidized granular medium, [ 59–61 ] which revealed a 4× increment in strength as the powder charge jammed.…”

Coupled Modeling of Sedimentary Basin and Geomechanics: A Modified Drucker–Prager Cap Model to Describe Rock Compaction in Tectonic Context

“…A commonly used model to describe the plastic behaviour, especially the compaction of porous media, is the Drucker-Prager Cap model (DiMaggio and Sandler, 1971). This model has been widely used to describe the behaviour of geomaterials (DiMaggio and Sandler, 1971;Grueschow and Rudnicki, 2005) as well as in applications where the focus is on mechanical compaction such as powder compaction modelling (Garner et al, 2015;Perez-Gandarillas et al, 2017). This model has a yield surface made of a line corresponding to a Drucker-Prager model to describe shear plasticity and an ellipsoidal Cap to describe compaction plasticity.…”

Analysis of densification mechanisms of dry granulated materials

“…During die compaction, the granules show different behaviour than feed powders and this observation had been reported many times in the literature as 'Loss of reworkability/loss of tabletability' leading to a reduction in tensile strength of tablets produced from granules [12][13][14]. It is also commonly observed that plastic materials are more sensitive to this phenomenon than brittle materials [15,16]. In the earlier paper [16], the understanding of how granules behave differently from feed powders had been studied for MCC101 powder.…”

“…It is also commonly observed that plastic materials are more sensitive to this phenomenon than brittle materials [15,16]. In the earlier paper [16], the understanding of how granules behave differently from feed powders had been studied for MCC101 powder. The analysis was based on Drucker-Prager Cap model (DPC), which characterizes the Elastic-Plastic behaviour of powders and takes into account the main properties of the compacted material (cohesion, internal friction, hardening and breaking under shearing stress).…”