Negative refraction of Lamb modes: A theoretical study
| Autor: | Benoît Gérardin, Jérôme Laurent, François Legrand, Alexandre Aubry, Claire Prada |
|---|---|
| Přispěvatelé: | emlyon business school, Institut Langevin - Ondes et Images, Université Paris Diderot - Paris 7 (UPD7)-ESPCI ParisTech-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Langevin - Ondes et Images (UMR7587) (IL), Sorbonne Université (SU)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Paris (UP)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Cloaking
FOS: Physical sciences Physics::Optics Physics - Classical Physics [PHYS.MECA.SOLID]Physics [physics]/Mechanics [physics]/Mechanics of the solides [physics.class-ph] 01 natural sciences law.invention Negative refraction law 0103 physical sciences [PHYS.MECA.SOLID]Physics [physics]/Mechanics [physics]/Solid mechanics [physics.class-ph] Boundary value problem 010306 general physics Duralumin 010301 acoustics ComputingMilieux_MISCELLANEOUS Physics [PHYS.MECA.VIBR]Physics [physics]/Mechanics [physics]/Vibrations [physics.class-ph] Flat lens Classical Physics (physics.class-ph) Laser Computational physics [PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph] [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic Ultrasonic sensor Phase velocity |
| Zdroj: | Physical Review B : Condensed matter and materials physics Physical Review B : Condensed matter and materials physics, American Physical Society, 2018, 98 (21), ⟨10.1103/PhysRevB.98.214114⟩ Physical Review B: Condensed Matter and Materials Physics (1998-2015) Physical Review B: Condensed Matter and Materials Physics (1998-2015), American Physical Society, 2018, 98 (21), ⟨10.1103/PhysRevB.98.214114⟩ |
| ISSN: | 0163-1829 1095-3795 1098-0121 1550-235X |
| DOI: | 10.1103/PhysRevB.98.214114⟩ |
| Popis: | This paper provides a theoretical investigation of negative refraction and focusing of elastic guided waves in a free-standing plate with a step-like thickness change. Under certain conditions, a positive phase velocity (forward) Lamb mode can be converted into a negative phase velocity (backward) mode at such interface, giving rise to negative refraction. A semi-analytical model is developed in order to study the influence of various parameters such as the material Poisson's coefficient, the step-like thickness, the frequency and the incidence angle. To this end, all the Lamb and shear horizontal propagating modes, but also a large number of their inhomogeneous and evanescent counterpart,s are taken into account. The boundary conditions applied to the stress-displacement fields at the thickness step yields an equation system. Its inversion provides the transmission and reflection coefficients between each mode at the interface. The step-like thickness and Poisson's ratio are shown to be key parameters to optimize the negative refraction process. In terms of material, Duralumin is found to be optimal as it leads to a nearly perfect conversion between forward and backward modes over broad frequency and angular ranges. An excellent focusing ability is thus predicted for a flat lens made of two symmetric thickness steps. Theoretical results are confirmed by a numerical FDTD simulation and experimental measurements made on an optimized Duralumin flat lens by means of laser interferometry. This theoretical study paves the way towards the optimization of elastic devices based on negative refraction, in particular for cloaking or super-focusing purposes. 8 pages, 6 figures |
| Databáze: | OpenAIRE |
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