Polar Metamaterials: A New Outlook on Resonance for Cloaking Applications
Abstract
Rotationally resonant metamaterials are leveraged to answer a longstanding question regarding the existence of transformation-invariant elastic materials and the ad hoc possibility of transformation-based passive cloaking in full plane elastodynamics. Combined with tailored lattice geometries, rotational resonance is found to induce a polar and chiral behavior, that is, a behavior lacking stress and mirror symmetries, respectively. The central, and simple, idea is that a population of rotating resonators can exert a density of body torques strong enough to modify the balance of angular momentum on which hang these symmetries. The obtained polar metamaterials are used as building blocks of a cloaking device. Numerical tests show satisfactory cloaking performance under pressure and shear probing waves, further coupled through a free boundary. The work sheds new light on the phenomenon of resonance in metamaterials and should help put transformation elastodynamics on equal footing with transformation acoustics and optics.
- Publication:
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Physical Review Letters
- Pub Date:
- February 2020
- DOI:
- 10.1103/PhysRevLett.124.084301
- arXiv:
- arXiv:1909.12437
- Bibcode:
- 2020PhRvL.124h4301N
- Keywords:
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- Physics - Applied Physics
- E-Print:
- Phys. Rev. Lett. 124, 084301 (2020)