Direct Measurement of Microscopic Force - Deformation Characteristics of a Single Particle

Abstract

Spring constant is one of the most important factors in DEM simulation, but it has been treated so far too arbitrary. To obtain more realistic description of the particle collision process for DEM, the force-displacement relationship was measured for polypropylene particles focusing on an individual particle with a system specially developed for it. The results indicated that the force is proportional to deformation x (Hookean) in the initial stage but to x1.5 (Hertzian) in the following stage. The former period is attributed to the effect of surface roughness. To predict spring constant close to the experimental value for the latter period, it was found essential to take into account the void and the projection's diameter of a sample particle.