Extreme wave skewing and dispersion spectra of anisotropic elastic plates

Abstract

Guided wave dispersion is commonly assessed by Fourier analysis of the field along a line, resulting in frequency-wavenumber dispersion curves. In anisotropic plates, a point source can generate multiple dispersion branches pertaining to the same modal surface, which arise due to the angle between the power flux and the wave vector. We show that this phenomenon is particularly pronounced near zero-group-velocity points, entailing up to six contributions along a given direction. Stationary phase points accurately describe the measurements conducted on a monocrystalline silicon plate.