Mechanical response of packings of nonspherical particles: A case study of two-dimensional packings of circulo-lines

• Type of Material: Article
• Authors: Jerry Zhang, Yale University; Kyle VanderWerf, Yale University; Chengling Li, Emory University; Shiyun Zhang, Yale University; Mark D Shattuck, The City College of New York; Corey S O'Hern, Yale University
• Language: English
• Date: 2021-07-27
• Publisher: AMER PHYSICAL SOC
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2021 American Physical Society
• Final Published Version (URL): http://dx.doi.org/10.1103/PhysRevE.104.014901
• Title of Journal or Parent Work: PHYSICAL REVIEW E
• Volume: 104
• Issue: 1
• Start Page: 014901
• End Page: 014901
• Grant/Funding Information: This work was also supported by the High Performance Computing facilities operated by Yale’s Center for Research Computing and computing resources provided by the Army Research Laboratory Defense University Research Instrumentation Program Grant No. W911NF-18-1-0252.; We acknowledge support from the Army Research Laboratory under Grant No. W911NF-17-1-0164 (C.O.), NSF Grants No. CBET-2002782 (C.O.) and No. CBET-2002797 (M.S.), and China Scholarship Council Grant No. 201906340202 (S.Z.).
• Keywords: Physical Sciences; Science & Technology; Physics, Fluids & Plasmas; Physics, Mathematical; Physics; STRESS

Abstract

We investigate the mechanical response of jammed packings of circulo-lines in two spatial dimensions, interacting via purely repulsive, linear spring forces, as a function of pressure P during athermal, quasistatic isotropic compression. The surface of a circulo-line is defined as the collection of points that is equidistant to a line; circulo-lines are composed of a rectangular central shaft with two semicircular end caps. Prior work has shown that the ensemble-Averaged shear modulus for jammed disk packings scales as a power law, (G(P))∼Pβ, 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 Râ 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, Gf, and from changes in the interparticle contact network, Gr, such that (G)=(Gf)+(Gr). We show that the shear modulus for low-pressure 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 (Gf) 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 for (G(P)).