Ordering and stress transmission in packings of straight and curved spherocylinders

Abstract

In this work we apply the discrete element method (DEM) to model packings of spherocylinders. The so-called composite spheres method was used to construct particles of different aspect ratio, surface shape and curvature. Using the DEM we probe in detail the effect of particle curvature and surface shape on packing morphology and stress transmission. We find that particle shape has a remarkable influence on both the packing morphology (quantified via the solid fraction, particle orientation distribution and radial distribution function) and stress transmission. Specifically, elongated particles have a high preference for horizontal alignment, whereas an increasing particle curvature leads to a more continuous (i.e. less discrete) particle orientation distribution. Generally, we observe that rough and curved particles have a stronger tendency for interlocking (in particular for small particle aspect ratios, i.e. \(AR=2\) and 3) leading to the formation of dense packing structures. In addition packings of rough and curved particles of small aspect ratios favor stress transmission in the gravitational direction, thus, limiting stress saturation with depth.