Elastic Waves

Elastic waves in helical waveguides

Waves in Wood: Elastic Waves in Cylindrically Orthotropic Materials

We consider elastic waves in materials with cylindrical orthotropy, this being a plausible model for wood. For time-harmonic motions, the problem is reduced to some coupled ordinary differential equations. Previously, these have been solved using the method of Frobenius (power-series expansions). We use Neumann series (expansions in Bessel functions of various orders), motivated by the known cl...

Scattering of elastic waves in damaged media.

The scattering of elastic waves in a medium with damage from microcracking is discussed. The influence of damage from penny-shaped microcracks within a homogeneous medium is considered. The microcracks are assumed to be randomly oriented and uniformly distributed. Explicit expressions are derived for the attenuation of longitudinal and shear elastic waves in terms of the damage parameter and th...

Topologically protected elastic waves in phononic metamaterials

Surface waves in topological states of quantum matter exhibit unique protection from backscattering induced by disorders, making them ideal carriers for both classical and quantum information. Topological matters for electrons and photons are largely limited by the range of bulk properties, and the associated performance trade-offs. In contrast, phononic metamaterials provide access to a much w...

Elastic waves as a Foucault pendulum?

The rotation of the Earth leads to a change in the equation of motion because of the Coriolis force. We study how Earth’s rotation affects elastic wave propagation. We show that the Coriolis force does not deflect seismic rays because the medium that carries the waves moves with Earth’s rotation. However, Earth’s rotation causes a weak traverse component of P-waves and a weak longitudinal compo...