Cyclic and Constant Shear SeSP-Doped Disk Packings

Superellipse sector particles (SeSPs) are generalizations of an ellipse that define shapes ranging from circles to rods to concave particles. We explore constant and cyclic simple shear of quasi-2-dimensional packings of disks and SeSPs in an annular-planar Couette cell. The packing is sheared quasi-statically and is affected by gravity and a constant pressure. An array of six cameras around the cell offers a 360° view, allowing tracking of the motion of the particles around the entire shear cell. We investigate how the SeSPs affect changes in the packing by quantifying reversibility of motion, shear velocity profiles, mean-squared displacements, and other structure measurements such as pair correlation. We compare how these values change under constant versus cyclic simple shear. Results have implications for industrial and pharmaceutical processes that involve irregular-shaped particle matter.