Multiscale toughness amplification in natural composites Journal Article uri icon



  • ABSTRACTHard biological materials such as bone and nacre exhibit remarkable mechanical performance, particularly in terms of fracture toughness, despite the weakness of their constituents. Mechanical performance of nacre and bone can largely be explained through their staggered microstructure where stiff inclusions of high aspect ratio are embedded in a softer matrix. The mineral inclusions provide hardness and stiffness while the organic matrix introduces ductility. The high performance of these natural structures is unmatched by any synthetic ceramic, which therefore makes them a substantial source of inspiration for development of new artificial materials. While the modulus and strength of these structures are well understood, fracture toughness remains unclear and controversial. In this work, chevron double cantilever beam fracture tests show that the interfaces in nacre have a low toughness, comparable to that of the tablets (in J terms). This highlights the important role of structural design on fracture toughness. At the next step, a fracture model is presented to explain the toughness amplification observed in natural staggered structures based on two essential extrinsic toughening mechanisms: crack bridging and process zone. The modeling results show that toughness can be further amplified by incorporating high concentrations of small inclusions with high aspect ratio. This conclusion is applicable to construction and optimization of natural and biomimetic composites.

publication date

  • January 1, 2012

has restriction

  • closed

Date in CU Experts

  • March 1, 2022 7:28 AM

Full Author List

  • Barthelat F; Rabiei R; Dastjerdi AK

author count

  • 3

Other Profiles

International Standard Serial Number (ISSN)

  • 0272-9172

Electronic International Standard Serial Number (EISSN)

  • 1946-4274

Additional Document Info


  • 1420


  • mrsf11-1420-oo01-02