Dynamic simulation of the centripetal packing of mono-sized spheres

This paper presents a study of the centripetal packing of mono-sized spherical particles simulated by means of the granular dynamic or discrete element method. A packing is formed by imposing an assumed centripetal force on particles randomly generated in a spherical space. Different from the conventional simulation techniques, dynamic information of individual particles including transient forces and trajectory is traced in the present simulation. Structural properties, such as packing density, radial distribution function, coordination number distribution and homogeneity, are analyzed, with particular reference to the effects of the magnitude of the centripetal force and the number of particles. Comparison with the literature results suggests that such a dynamic model can satisfactorily simulate the dynamics of forming a packing and produce more realistic structural information. In particular, it is confirmed that a centripetal packing is not homogeneous in structure, becoming looser as its size or the number of particles increases. The packing has a limit packing density of 0.637–0.645, an overall mean coordination number of around 6.0 and a radial distribution function of clear split second peak. The centripetal force affects the rate of densification and the mean coordination number but not packing density and radial distribution function.