Open Access

ARTICLE

Flaw tolerant bulk and surface nanostructures of biological systems

by Huajian Gao¹, Baohua Ji¹, Markus J. Buehler¹, Haimin Yao¹

1 Max Planck Institute for Metals Research, Heisenbergstrasse 3, D-70569, Stuttgart, Germany

Molecular & Cellular Biomechanics 2004, 1(1), 37-52. https://doi.org/10.3970/mcb.2004.001.037

Abstract

Bone-like biological materials have achieved superior mechanical properties through hierarchical composite structures of mineral and protein. Gecko and many insects have evolved hierarchical surface structures to achieve extraordinary adhesion capabilities. We show that the nanometer scale plays a key role in allowing these biological systems to achieve their superior properties. We suggest that the principle of flaw tolerance may have had an overarching influence on the evolution of the bulk nanostructure of bone-like materials and the surface nanostructure of gecko-like animal species. We demonstrate that the nanoscale sizes allow the mineral nanoparticles in bone to achieve optimum fracture strength and the spatula nanoprotrusions in Gecko to achieve optimum adhesion strength. In both systems, strength optimization is achieved by restricting the characteristic dimension of the basic structure components to nanometer scale so that crack-like flaws do not propagate to break the desired structural link. Continuum modeling and atomistic simulations have been conducted to verify the concept of flaw tolerance at nanoscale.

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