Figure 11.

In (a), starting configurations are sampled with filament centreline positions arranged on a hexagonal lattice. Structures of varying aspect ratio are taken by selecting points within a stadium boundary with varying dimensions. Lattice vertices circled blue correspond to ‘pruned’ filament positions removed to maintain target N. In (b), the dimensions of the lattice configurations sampled for N = 181 filaments are shown, corresponding to sampling with stadium boundary aspect ratios α = 1−7.5, with example configurations shown as highlighted. In (c), the energy densities of relaxed lattice configurations are shown at twist , for two values of ductility σ/d. For brittle case, σ/d = 0.4, α ≃ 3 tapes are favoured, while for the relative ductile case, σ/d = 1.0, roughly cylindrical bundles (α ≃ 1) are optimal.