Figure 5
From: The avian egg exhibits general allometric invariances in mechanical design
Failure characteristics of avian eggshells. (a) Experimental fracture force and simulated buckling force. (b) The displacement to shell thickness ratio δ/t at fracture (red squares) and buckling (green triangles). Much of the displacement comes from the bending deformation (flattening) near the contact zone. (c) Normalized fracture strength is approximately invariant: σ f/E = 0.73 ± 0.16%, or σ f = E/137, see Fig. S7. A theoretical upper limit of σ f is between E/2π and E/30 (ref.38). Fracture data are obtained from the compression test; buckling data are predicted by FEM simulations. See Supplementary Dataset 2 for details on the source of bird images.
