Biologically inspired crack delocalization in a high strain-rate environment

Christian Knipprath, Ian P. Bond, Richard S. Trask

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Biological materials possess unique and desirable energy-absorbing mechanisms and structural characteristics worthy of consideration by engineers. For example, high levels of energy dissipation at low strain rates via triggering of crack delocalization combined with interfacial hardening by platelet interlocking are observed in brittlematerials such as nacre, the iridescent material in seashells. Such behaviours find no analogy in current engineering materials. The potential to mimic such toughening mechanisms on different length scales now exists, but the question concerning their suitability under dynamic loading conditions and whether these mechanisms retain their energy-absorbing potential is unclear. This paper investigates the kinematic behaviour of an 'engineered' nacre-like structure within a high strain-rate environment. A finite-element (FE) model was developed which incorporates the pertinent biological design features. A parametric study was carried out focusing on (i) the use of an overlapping discontinuous tile arrangement for crack delocalization and (ii) application of tile waviness (interfacial hardening) for improved post-damage behaviour. With respect to the material properties, the model allows the permutation and combination of a variety of different material datasets. The advantage of such a discontinuous material shows notable improvements in sustaining high strain-rate deformation relative to an equivalent continuous morphology. In the case of the continuous material, the shockwaves propagating through the material lead to localized failure while complex shockwave patterns are observed in the discontinuous flat tile arrangement, arising from platelet interlocking. The influence of the matrix properties on impact performance is investigated by varying the dominant material parameters. The results indicate a deceleration of the impactor velocity, thus delaying back face nodal displacement. A final series of FE models considered the identification of an optimized configuration as a function of tile waviness and matrix properties. In the combined model, the optimized configuration was capable of stopping the ballistic threat, thus indicating the potential for bioinspired toughened synthetic systems to defeat high strain-rate threats.

LanguageEnglish
Pages665-676
Number of pages12
JournalJournal of the Royal Society, Interface
Volume9
Issue number69
DOIs
StatusPublished - 7 Apr 2012

Fingerprint

Nacre
Animal Shells
Strain rate
Blood Platelets
Cracks
Tile
Deceleration
Biomechanical Phenomena
Platelets
Hardening
Toughening
Ballistics
Biological materials
Energy dissipation
Materials properties
Identification (control systems)
Kinematics
Engineers

Keywords

  • Dynamic impact
  • Finite-element modelling
  • Interlocking
  • Material discontinuity
  • Nacre

ASJC Scopus subject areas

  • Biophysics
  • Biotechnology
  • Bioengineering
  • Biomedical Engineering
  • Biomaterials
  • Biochemistry

Cite this

Biologically inspired crack delocalization in a high strain-rate environment. / Knipprath, Christian; Bond, Ian P.; Trask, Richard S.

In: Journal of the Royal Society, Interface, Vol. 9, No. 69, 07.04.2012, p. 665-676.

Research output: Contribution to journalArticle

Knipprath, Christian ; Bond, Ian P. ; Trask, Richard S. / Biologically inspired crack delocalization in a high strain-rate environment. In: Journal of the Royal Society, Interface. 2012 ; Vol. 9, No. 69. pp. 665-676.
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