Wave dispersion in heterogeneous solids due to scattering within the microstructure is examined. Underlying physics is explored. A theory based on a quasi-harmonic normal model description of the scattering wave energy is developed and compared with phenomenological nonlinear anelasticity models of wave propagation in heterogeneous media.

Ultrasonic waves are highly sensitive to microstructural variations in materials and have been used extensively to investigate anharmonic effects in various metals and alloys[1-3]. A major focus of these studies is on the higher order elastic constants and their relation to the microstructure of the material. Ultrasonic techniques have also proven quite useful for characterizing the stress stat...

The resistance against rolling of a rigid cylinder on a flat viscous surface is investigated. We found that the rolling-friction coefficient reveals strongly non-linear dependence on the cylinder’s velocity. For low velocity the rolling-friction coefficient rises with velocity due to increasing deformation rate of the surface. For larger velocity, however, it decreases with velocity according t...

S U M M A R Y Lateral variations in mantle anelasticity (Q) are important for understanding the Earth’s thermal and chemical structure in the mantle. In the past decades, preliminary global 3-D tomographic Q models have been developed based upon the assumption that traveltime (phase delay) anomalies are due to the Earth’s elastic (velocity) structure whereas amplitude anomalies are dominated by...