title: Particle shape effects on the stress response of granular packings.
abstract: We present measurements of the stress response of packings formed from a wide range of particle shapes. Besides spheres these include convex shapes such as the Platonic solids, truncated tetrahedra, and triangular bipyramids, as well as more complex, non-convex geometries such as hexapods with various arm lengths, dolos, and tetrahedral frames. All particles were 3D-printed in hard resin. Well-defined initial packing states were established through preconditioning by cyclic loading under given confinement pressure. Starting from such initial states, stress-strain relationships for axial compression were obtained at four different confining pressures for each particle type. While confining pressure has the largest overall effect on the mechanical response, we find that particle shape controls the details of the stress-strain curves and can be used to tune packing stiffness and yielding. By correlating the experimentally measured values for the effective Young's modulus under compression, yield stress and energy loss during cyclic loading, we identify trends among the various shapes that allow for designing a packing's aggregate behavior.
authors.affiliation: James Franck Institute & Department of Physics, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA. h-jaeger@uchicago.edu.
authors.forename: Athanasios G
authors.initials: AG
authors.lastname: Athanassiadis
authors.forename: Marc Z
authors.initials: MZ
authors.lastname: Miskin
authors.forename: Paul
authors.initials: P
authors.lastname: Kaplan
authors.forename: Nicholas
authors.initials: N
authors.lastname: Rodenberg
authors.forename: Seung Hwan
authors.initials: SH
authors.lastname: Lee
authors.forename: Jason
authors.initials: J
authors.lastname: Merritt
authors.forename: Eric
authors.initials: E
authors.lastname: Brown
authors.forename: John
authors.initials: J
authors.lastname: Amend
authors.forename: Hod
authors.initials: H
authors.lastname: Lipson
authors.forename: Heinrich M
authors.initials: HM
authors.lastname: Jaeger