In-plane backward and Zero-Group-Velocity guided modes in rigid and soft strips

Abstract

Elastic waves guided along bars of rectangular cross section exhibit complex dispersion. This paper studies in-plane modes propagating at low frequencies in thin isotropic rectangular waveguides through experiments and numerical simulations. These modes result from the coupling at the edge between the first order shear horizontal mode $S{H}_0$ of phase velocity equal to the shear velocity $V_T$ and the first order symmetrical Lamb mode $S_0$ of phase velocity equal to the plate velocity $V_P$. In the low frequency domain, the dispersion curves of these modes are close to those of Lamb modes propagating in plates of bulk wave velocities $V_P$ and $V_T$. The dispersion curves of backward modes and the associated ZGV resonances are measured in a metal tape using non-contact laser ultrasonic techniques. Numerical calculations of in-plane modes in a soft ribbon of Poisson's ratio $\nu \approx 0.5$ confirm that, due to very low shear velocity, backward waves and zero group velocity modes exist at frequencies that are hundreds of times lower than ZGV resonances in metal tapes of the same geometry. The results are compared to theoretical dispersion curves calculated using the method provided in Krushynska and Meleshko (J. Acoust. Soc. Am $129$, 2011).

arXiv comment9 pages, 9 figures

References in corpus (5)

• Imaging Gigahertz Zero-Group-Velocity Lamb Waves
• Surface scattering analysis of phonon transport in the quantum limit using an elastic model
• Laser induced Zero-Group Velocity resonances in Transversely Isotropic cylinder
• Temporal behavior of laser induced elastic plate resonances
• Backward Propagating Acoustic Waves in Single Gold Nanobeams

Cited by in corpus (4)

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• Dirac cones and chiral selection of elastic waves in a soft strip
• Viscoelastic dynamics of a soft strip subject to a large deformation
• Evidence of experimental three-wave resonant interactions between two dispersion branches