Framework or lattice structures can be remarkably strong despite their very low density. Using a very precise technique known as projection microstereolithography, Zheng et al. fabricated octet microlattices from polymers, metals, and ceramics. The design of the lattices meant that the individual struts making up the materials did not bend under pressure. The materials were therefore exceptionally stiff, strong, and lightweight.
Architecture of stretch-dominated and bend-dominated unit cells and lattices. (A) Mechanical response to compressive loading of a stretch-dominated octet-truss unit cell. (B) Octet-truss unit cells packed into a cubic microlattice. (C) SEM image of a stretch-dominated lattice material composed of a network of octet-truss unit cells. (D) Mechanical response to compressive loading of a bend-dominated tetrakaidecahedron unit cell. (E) Tetrakaidecahedron unit cell packed into a cubic bend-dominated lattice (Kelvin foam). (F) SEM image of a bend-dominated lattice composed of a network of tetrakaidecahedron unit cells. Zheng et al.