Mechanical response of packings of non-spherical particles: A case study of 2D packings of circulo-lines

Abstract

We investigate the mechanical response of jammed packings of circulo-lines, interacting via purely repulsive, linear spring forces, as a function of pressure P during athermal, quasistatic isotropic compression. Prior work has shown that the ensemble-averaged shear modulus for jammed disk packings scales as a power-law, G(P ) ∼ P β , with β ∼ 0.5, over a wide range of pressure. For packings of circulo-lines, we also find robust power-law scaling of G(P ) over the same range of pressure for aspect ratios R 1.2. However, the power-law scaling exponent β ∼ 0.8-0.9 is much larger than that for jammed disk packings. To understand the origin of this behavior, we decompose G into separate contributions from geometrical families, G f , and from changes in the interparticle contact network, Gr, such that G = G f + Gr . We show that the shear modulus for lowpressure geometrical families for jammed packings of circulo-lines can both increase and decrease with pressure, whereas the shear modulus for low-pressure geometrical families for jammed disk packings only decreases with pressure. For this reason, the geometrical family contribution G f is much larger for jammed packings of circulo-lines than for jammed disk packings at finite pressure, causing the increase in the power-law scaling exponent.