(c) (d)
Figure 17. Force chain plots for L-L and L-S contacts. (a) 25% large particles; (b) 50% large particles; (c) 75% large particles; (d) 100% large particles.
The force chains for L-L, L-S and S-S contacts are illustrated in Figure 18. For 100% large and 75% large particle systems, the effect of S-S contacts is negligible due to the insufficient number of small particles. However, for binary systems with a fraction of large particles at 50% and 25%, the effect of S-S contacts on force transmission is very significant. When the number of small particles is sufficiently high, large particles are totally separated from each other, immersed in a sea of small particles. The force chain plots of Figure 18 (b) are also consistent with the experimental observation that the bulk flow behavior of the 50:50 mixture is similar to that of small particles only. For both of these particle systems, the S-S contacts are the dominate mechanism for transmitting forces.