Geometric effects on impact mitigation in architected auxetic metamaterials

T. Gärtner*, S. J. van den Boom, J. Weerheijm, L. J. Sluys

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Lightweight materials used for impact mitigation must be able to resist impact and absorb the maximum amount of energy from the impactor. Auxetic materials have the potential to achieve high resistance by drawing material into the impact zone and providing higher indentation and shear resistance. However, these materials must be artificially designed, and the large deformation dynamic effects of the created structures must be taken into consideration when deciding on a protection concept. Despite their promise, little attention has been given to understanding the working mechanisms of high-rate and finite deformation effects of architected auxetic lattice structures. This study compares the static and dynamic elastic properties of different auxetic structures with a honeycomb structure, a typical non-auxetic lattice, at equivalent mass and stiffness levels. In this study, we limit the investigation to elastic material behavior and do not consider contact between the beams of the lattices. It is demonstrated that the equivalent static and dynamic properties of individual lattices at an undeformed state are insufficient to explain the variations observed in impact situations. In particular, the initial Poisson's ratio does not determine the ability of a structure to resist impact. To gain a thorough comprehension of the overall behavior of these structures during localized, high rate compression, the evolution of the elastic tangent properties under compression and shear deformation was monitored, leading to a more profound understanding. Observations made in one configuration of stiffness and mass are replicated and analyzed in related configurations.

Original languageEnglish
Article number104952
Number of pages19
JournalMechanics of Materials
Volume191
DOIs
Publication statusPublished - 2024

Keywords

  • Architected materials
  • Elasticity
  • Geometric nonlinearity
  • Impact mitigation
  • Lattice structures

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