There are two main classes of physics-based models for two-dimensional cellular materials: packings of repulsive disks and the vertex model. These models have several disadvantages. For example, disk interactions are typically a function of particle overlap, yet the model assumes that disks remain circular during overlap. The shapes of the cells can vary in the vertex model, however, the packing fraction is fixed at φ = 1. Here, we describe the deformable particle model (DPM), where each particle is a polygon composed of a large number of vertices. The total energy includes three terms: two quadratic terms to penalize deviations from the preferred particle area a0 and perimeter p0 and a repulsive interaction between DPM polygons that penalizes overlaps. We performed simulations to study jammed DPM packings as a function of asphericity, A = p 2 0 /4πa0. We show that the packing fraction at jamming onset φJ (A) grows with increasing A, reaching confluence at A * ≈ 1.16. A * corresponds to the value at which DPM polygons completely fill the cells obtained from surface-Voronoi tessellation. Further, we find that DPM polygons develop invaginations for A > A * with excess perimeter that grows linearly with A − A * . We also confirm that DPM packings are solid-like for A > A * and A < A * .

No abstract