Models for the Mechanics of Joining Dissimilar Materials - Structural Interfaces and Attachments in Biology - page 61

Fig. 3.11 The stress-strain behavior of a metal such as steel involves a characteristic concave
down shape, with a drop in stiffness following a yield point corresponding to the onset of
permanent “plastic” deformation. The stress-strain behavior of a biological material such as a
tendon involves a characteristic concave up shape, with a rise in stiffness over a much larger elastic
region
Tissues are nevertheless resilient to tears, with many mechanisms identified within
their fibrous protein structures that enhance toughening across length scales [ 50 - 52 ].
However, the body seems to take few chances and uses many schemes for
reducing stresses, including tailoring of material and morphological properties of
tissues to eliminate free edge singularities, and tailoring of joints to maximize peel
resistance.
Acknowledgments This work was supported in part by the National Institutes of Health
(HL079165) and by the Johanna D. Bemis trust. Y.L. received a fellowship from the Fannie
Stephens Murphy Memorial Fund.
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