Linear Elastic Waves

Wavefronts of Linear Elastic Waves: Local Convexity and Modeling

Seismic techniques incorporating high frequency asymptotic representation of the 3D elastic Green's function require eecient solution methods for the computation of traveltimes. For nite diierence eikonal solvers, upwind diierences are requisite to sharply resolve discontinuities in the traveltime derivatives. In anisotropic media the direction of energy propagation is not in general tangent to...

Interaction of highly nonlinear solitary waves with linear elastic media.

We study the interaction of highly nonlinear solitary waves propagating in granular crystals with an adjacent linear elastic medium. We investigate the effects of interface dynamics on the reflection of incident waves and on the formation of primary and secondary reflected waves. Experimental tests are performed to correlate the linear medium geometry, materials, and mass with the formation and...

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...

Measuring the linear and nonlinear elastic properties of brain tissue with shear waves and inverse analysis.

We use supersonic shear wave imaging (SSI) technique to measure not only the linear but also the nonlinear elastic properties of brain matter. Here, we tested six porcine brains ex vivo and measured the velocities of the plane shear waves induced by acoustic radiation force at different states of pre-deformation when the ultrasonic probe is pushed into the soft tissue. We relied on an inverse m...