Particle shape effect on the structural evolution and force propagation inside the three-dimensional sandpile.

Abstract

This paper employs the discrete element method to examine the impact of particle shape on the pressure dip phenomenon and structural characterization of the three-dimensional sandpiles. Particular attention has been given to the underlying mechanism in the sandpile, which arises from the interplay of the initial created structure and the induced changes in the subsequent deposition process. Different aspect ratios produced different initial local geometry. The contact vector and strong contact force rotated away from the z-axis when the aspect ratio deviates from 1.0. The flat particles had a better memory of initial structures under the subsequent deposition process, which plays a vital role in force transmission and stress propagation. However, when the aspect ratio approaches 1.0, the stress state behaves as a joint result of maintained and gained contacts. For a certain range of aspect ratios, the newly generated interactions of elongated particles induced the major stress in the horizontal plane, which thus produces a significant pressure dip phenomenon. The results indicated that complex models accounting for contact creation are required to capture the pressure profile.