Evolution of load transfer between hydroxyapatite and collagen during creep deformation of bone

A. C. Deymier-Black*, F. Yuan, A. Singhal, J. D. Almer, L. C. Brinson, D. C. Dunand

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

While the matrix/reinforcement load-transfer occurring at the micro- and nanoscale in nonbiological composites subjected to creep deformation is well understood, this topic has been little studied in biological composites such as bone. Here, for the first time in bone, the mechanisms of time-dependent load transfer occurring at the nanoscale between the collagen phase and the hydroxyapatite (HAP) platelets are studied. Bovine cortical bone samples are subjected to synchrotron X-ray diffraction to measure in situ the evolution of elastic strains in the crystalline HAP phase and the evolution of viscoelastic strains accumulating in the mineralized collagen fibrils under creep conditions at body temperature. For a constant compressive stress, both types of strains increase linearly with time. This suggests that bone, as it deforms macroscopically, is behaving as a traditional composite, shedding load from the more compliant, viscoelastic collagen matrix to the reinforcing elastic HAP platelets. This behavior is modeled by finite-element simulation carried out at the fibrillar level.

Original languageEnglish (US)
Pages (from-to)253-261
Number of pages9
JournalActa Biomaterialia
Volume8
Issue number1
DOIs
StatePublished - Jan 1 2012

Keywords

  • Bone
  • Creep
  • Load-transfer
  • Synchrotron
  • X-ray diffraction

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Biochemistry
  • Biomedical Engineering
  • Molecular Biology

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