Non-spherical particle packing

Compaction process of rods under tapping
Packing structures of rods with different aspect ratios
Random packing structures of ellipsoids


Compaction process of rods under tapping

        Packing of rods evolve from isotropic phase towards nematic phase under external vertical tapping. It is demonstrated that the relaxation time of the system obeys an Arrhenius law in which the tapping intensity plays the role of the effective temperature. It is thus suggested that the macroscopic behavior of non-thermal granular system can be descried using some thermodynamic quantities, and its relaxation time is very similar to the aging process of glass systems. The work has been published on Phys. Rev. E 85, 051311 (2012).  ( PDF )

Figure: Fitting of (a) orientational order parameter and (b) packing fraction as a function of the tapping number, using both KWW stretched-exponential and inverse logarithmic laws.




Packing structures of rods with different aspect ratios

        Packing of rods with different aspect ratios is studied using synchrotron X-ray in-line phase contrast imaging techniques. The relationships between local packing structures, i.e., contact number and free volume, and particle shape is analyzed. The work has been published on Chinese Phys. B 23, 044501 (2014).  ( PDF )

Figure: The 3D structure of rod packing with different aspect ratios.




Random packing structures of ellipsoids

        The random packing structures of ellipsoid packing are obtained using medical CT. We found that the particle non-spherical effect induce an effective polydispersity, and the non-spherical packing can be mapped onto a polydispersed spherical packing. In addition, the asphericity or polydispersity reduces the correlation of the packing, the local packing structure of which can thus be described using a mean-field model, i.e., the granocentric model. The work has been published on Soft Matter 10, 990 (2014).  ( PDF )

Figure: (a) The local contacts of ellipsoids. (b) The polydispersed sphere packing model.