Fig. 6: The auxeticity of periodic homogeneous metamaterials.
a The paper prototype of periodic homogeneous metamaterials with quadrilateral ring under different configurations (adjustable angles of 22.5°, 45°, 67.5°, 90°, 112.5°, 135°, and 157.5°). The geometry of quadrilateral ring can be continuous adjusted and fixed by 3D-printed plastic connecting components with detachable pins, see detail in method of Fabrication and experiment testing of periodic homogeneous quadrilateral ring metamaterials. b The paper prototype snapshots of an example of periodic homogeneous metamaterial at the strain of 0, 1/3ε, 2/3ε and 3/3ε under compression deformation (example: CIII rings with the adjustable angle of 67.5°). The side length l of the physical prototype of paper element is 30 mm. See “Methods” for the details about periodic homogeneous metamaterial fabrication. c The Poisson’s ratio of periodic homogeneous metamaterial varied as a function of adjustable angle for compression deformation. The solid line represents theoretical results, and the discrete hollow points denote experimental results. d The paper prototype snapshots of an example of periodic homogeneous metamaterial at the strain of 0, 1/3ε, 2/3ε, and 3/3ε under tension deformation (example: CI rings with the adjustable angle of 67.5°). e The Poisson’s ratio of periodic homogeneous metamaterial varied as a function of adjustable angle for tension deformation. Source data are provided as a Source Data file.
