Polarization bandgaps and fluid-like elasticity in fully solid elastic metamaterials Articles uri icon

authors

  • MA, GUANCONG
  • FU, CAIXING
  • WANG, GUANGHAO
  • DEL HOUGNE, PHILIPP
  • CHRISTENSEN, JOHAN
  • LAI, YUN
  • SHENG, PING

publication date

  • November 2016

start page

  • 1

end page

  • 8

volume

  • 7 (13536)

International Standard Serial Number (ISSN)

  • 2041-1723

abstract

  • Elastic waves exhibit rich polarization characteristics absent in acoustic and electromagnetic waves. By designing a solid elastic metamaterial based on three-dimensional anisotropic locally resonant units, here we experimentally demonstrate polarization bandgaps together with exotic properties such as 'fluid-like' elasticity. We construct elastic rods with unusual vibrational properties, which we denote as 'meta-rods'. By measuring the vibrational responses under flexural, longitudinal and torsional excitations, we find that each vibration mode can be selectively suppressed. In particular, we observe in a finite frequency regime that all flexural vibrations are forbidden, whereas longitudinal vibration is allowed-a unique property of fluids. In another case, the torsional vibration can be suppressed significantly. The experimental results are well interpreted by band structure analysis, as well as effective media with indefinite mass density and negative moment of inertia. Our work opens an approach to efficiently separate and control elastic waves of different polarizations in fully solid structures.

keywords

  • Negative refractive-index
    Mechanical metamaterials
    Acoustic metamaterials
    Transformation
    Resonances
    Waves
    Sound
    Cloak