Figure 9. Comparison of the τpre from experiments and
DEM simulations.
In order to compare the experimental packing density with the DEM
predictions, the experimental packing density is converted to solid
fraction. Solid fraction is calculated by dividing the packing density
with the true density of the glass beads, i.e. 2500
kg/m3. The variation of solid fraction with
composition is shown in Figure 10. The solid fraction in both the
experiment and DEM simulations is calculated by recording the position
of the top boundary under the same 2000 Pa pre-shear load. For both
sizes of monodispersed spherical beads, the predicted and measured solid
fraction is similar with a value around 0.6. In addition, the solids
fraction for the binary mix is higher than that of the monodispersed
particles, similar to what was observed by Vallejo12.
The DEM predictions of solid fraction are able to reproduce the
experimental measurements quite well.