Random Packings of Polydisperse Adhesive Microspheres with Gaussian Size Distribution

We investigate random loose packings of polydisperse spherical micro-particles by means of a specially developed adhesive DEM approach. The results show that the differences of the packing properties (packing fraction and mean coordination number) between polydisperse packings and monodisperse cases with the same mean particle radius are well described by a quadratic function of the normalized standard deviation of the particle size (σ). Based on the previous literature (Liu, Li, Chen, 2016), we can uniquely predict the packing fraction of polydisperse adhesive packings via σ and a dimensionless adhesion parameter (Ad). Furthermore, by looking into the microstructure of the polydisperse packings, we found that the typical functions such as radial distribution function and angular distance distribution function, which are widely used to characterize the monodisperse packing structures, are not applicable. The local characteristic peaks are erased due to the size polydispersity.