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Title: Elastodynamic metasurface: Depolarization of mechanical waves and time effects

We report the concept of microstructured surfaces with inner resonance in the field of elastodynamics, so-called elastodynamic metasurfaces. Such metasurfaces allow for wavefield manipulation of mechanical waves by tuning the boundary conditions at specific frequencies. In particular, they can be used to depolarize elastic waves without introducing heterogeneities in the medium itself; the physical means to do so in homogeneous elastic media used to remain, surprisingly, an open question while depolarization is commonplace in electromagnetism. The principle relies on the anisotropic behaviour of a subwavelength array of resonators: Their subwavelength configuration confines the Bragg interferences scattered by resonators into a boundary layer. The effective behaviour of the resonating array is expressed with homogenization as an unconventional impedance, the frequency-dependence, and anisotropy of which lead to depolarization and time effects. The concept of the elastodynamic metasurface is tested experimentally and results bear testament to its efficacy and robustness. Elastodynamic metasurfaces are easily realized and analytically predictable, opening new possibilities in tomography techniques, ultrasonics, geophysics, vibration control, materials and structure design.
Authors:
 [1] ;  [2] ;  [3]
  1. Ecole Nationale des Travaux Publics de l'Etat, Université de Lyon, LGCB, UMR CNRS 5513, Vaulx-en-Velin (France)
  2. Acoustics Research Center, University of Salford, Newton Building, Salford M5 4WT (United Kingdom)
  3. Department of Civil Engineering, University of Bristol, Queen's Building, Bristol BS8 1TR (United Kingdom)
Publication Date:
OSTI Identifier:
22413111
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; BOUNDARY CONDITIONS; BOUNDARY LAYERS; DEPOLARIZATION; ELECTROMAGNETISM; FREQUENCY DEPENDENCE; IMPEDANCE; INTERFERENCE; MICROSTRUCTURE; RESONANCE; RESONATORS; SURFACES; TOMOGRAPHY; ULTRASONIC WAVES