Yuchen Zhao, Duke University

Hyper-static Packings Made of Granular Hexapods

Columns are made of convex non-cohesive grains like sand collapse after being released from initial positions. On the other hand, various architectures built by concave grains can maintain stability. We explore why these structures are stable, and how stable they can be. We performed experiments by randomly pouring identical star-shape particles into hollow cylinders left on glass and a rough base, and observed stable granular columns after lifting the cylinders. Particles have six 9mm arms, which extend symmetrically in the xyz directions. Both the probability of creating a stable column and mechanical stability aspects have been investigated. In order to understand structure leading to stability, 3D CT scan reconstructions of columns have been done and contact number, contact position and packing density will be discussed.