ABSTRACT
We have used 3D Discrete Element Method (DEM) simulations to carry out our numerical experiments. The particles are non-rigid and can undergo small deformations on contact with other particles. The degree of deformation at a contact will determine the contact force experienced by the two particles forming the contact. We have used the Hertz-Kuwabara-Kono contact force model to represent the normal forces and a linear damped harmonic oscillator model to represent the tangential contact forces. The material properties such as theYoung’s modulus and the Poisson ratio are used to determine the contact force parameters (Schafer, Dippel & Wolf 1996). The Young’s moduli and the Poisson ratios for MCC and Sucrose are 9.08 × 109 Pa and 2.70 × 1010 Pa, and 0.3 and 0.25, respectively (Alderborn & Nystrom 1996). Interparticle substrate friction has been accounted for by including Coulomb’s friction criteria (Aastrom, Herrman & Timonen 2000) thereby, adding two more
control parameters: the coefficient of kinetic friction µk and the coefficient of static friction µstat . All the simulations are performed in two stages: the particles are allowed to settle under gravity followed by constant strain uniaxial compaction at 1 mm/s. Both phases of the simulations are carried out for a preset interval of time. Further details of the interparticle forces and the numerical simulation can be found in (Dutt, Hancock, Bentham & Elliott 2005).
