Interaction dynamics between concave and circular granular particles undergoing cyclic shear

We study the dynamics of superellipse sector particles (SeSPs) in a bidisperse monolayer of disks undergoing oscillatory cyclic shear. The SeSP generating function allows for continuous parameterization of corner sharpness, aspect ratio, and opening aperture, reproducing a wide variety of particle shapes including rods, discs, U-shaped staples and, in our study, C-shaped semi-circles. SeSPs are placed in an annular planar Couette cell, oriented vertically ad sheared from the top. We minimize SeSP-SeSP interactions by keeping the number of SeSPs small and focus our attention on the behavior of the SeSPs in response to the motion of the surrounding circular disks. Particles translational and rotational motions are tracked with video analysis, and we look for reversible and irreversible motions and correlate these with the surrounding particle configurations.