Optimal length scales emerging from shear load transfer in natural materials: Application to carbon-based nanocomposite design

Xiaoding Wei, Mohammad Naraghi, Horacio D. Espinosa*

*Corresponding author for this work

Research output: Contribution to journalArticle

112 Scopus citations

Abstract

Numerous theoretical and experimental studies on various species of natural composites, such as nacre in abalone shells, collagen fibrils in tendon, and spider silk fibers, have been pursued to provide insight into the synthesis of novel bioinspired high-performance composites. However, a direct link between the mechanical properties of the constituents and the various geometric features and hierarchies remains to be fully established. In this paper, we explore a common denominator leading to the outstanding balance between strength and toughness in natural composite materials. We present an analytical model to link the mechanical properties of constituents, their geometric arrangement, and the chemistries used in their lateral interactions. Key critical overlap length scales between adjacent reinforcement constituents, which directly control strength and toughness of composite materials, emerge from the analysis. When these length scales are computed for three natural materials-nacre, collagen molecules, and spider silk fibers-very good agreement is found as compared with experimental measurements. The model was then used to interpret load transfer capabilities in synthetic carbon-based materials through parametrization of in situ SEM shear experiments on overlapping multiwall carbon nanotubes.

Original languageEnglish (US)
Pages (from-to)2333-2344
Number of pages12
JournalACS nano
Volume6
Issue number3
DOIs
StatePublished - Mar 27 2012

Keywords

  • nanocomposites
  • natural materials
  • shear load transfer
  • toughness

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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