Exploiting Structural Instability to Design Architected Materials Having Essentially Nonlinear Stiffness

Jonathan Bunyan, Sameh H Tawfick

Research output: Contribution to journalArticle

Abstract

Architected materials enable unusual mechanical behavior, that is, inaccessible to existing materials. This study demonstrates an architected cell structure having a constant stress plateau extending for a very wide range of strains followed by hardening at large strains. This essentially nonlinear stiffness has attractive applications ranging from static stress redistribution to acoustic wave tailoring, yet materials exhibiting this behavior are challenging to realize practically. The authors propose designs which realize controlled essentially nonlinear response using coordinated elastic strut buckling. The authors exploit controlled asymmetric buckling of the struts’ structure to precisely tailor a wide flat stress plateau in elastomeric materials. The authors experimentally measure the effects of structural geometry and provide design guidelines to tune this exotic behavior. The authors utilize finite element simulations to isolate the core strain energy storage mechanisms governing the deformation. Owing to the 2D nature of the design, these materials can be readily fabricated in a variety of materials using laser cutting, extrusion, molding, 3D printing, and micro-lithographic methods. The proposed designs have wider constant stress plateaus than open cell foams, and as such offer new opportunities in orthopedic design, protection, packaging, as well as sonic vacua and non-reciprocal acoustic metamaterials.

Original languageEnglish (US)
Article number1800791
JournalAdvanced Engineering Materials
Volume21
Issue number2
DOIs
StatePublished - Feb 1 2019

Fingerprint

stiffness
Stiffness
struts
plateaus
Struts
buckling
Buckling
Extrusion molding
laser cutting
orthopedics
acoustics
Metamaterials
Orthopedics
energy storage
Strain energy
cells
packaging
foams
printing
hardening

Keywords

  • architected materials
  • buckling
  • cushioning
  • nonlinear materials
  • shock absorption

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Exploiting Structural Instability to Design Architected Materials Having Essentially Nonlinear Stiffness. / Bunyan, Jonathan; Tawfick, Sameh H.

In: Advanced Engineering Materials, Vol. 21, No. 2, 1800791, 01.02.2019.

Research output: Contribution to journalArticle

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