The influence of packing structure and interparticle forces on ultrasound transmission in granular media.
| Autor: | Zhai C; Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, MD 21218., Herbold EB; Atmospheric, Earth, & Energy Division, Lawrence Livermore National Laboratory, Livermore, CA 94550., Hurley RC; Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, MD 21218; rhurley6@jhu.edu.; Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218. |
|---|---|
| Jazyk: | angličtina |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2020 Jul 14; Vol. 117 (28), pp. 16234-16242. Date of Electronic Publication: 2020 Jun 29. |
| DOI: | 10.1073/pnas.2004356117 |
| Abstrakt: | Ultrasound propagation through externally stressed, disordered granular materials was experimentally and numerically investigated. Experiments employed piezoelectric transducers to excite and detect longitudinal ultrasound waves of various frequencies traveling through randomly packed sapphire spheres subjected to uniaxial compression. The experiments featured in situ X-ray tomography and diffraction measurements of contact fabric, particle kinematics, average per-particle stress tensors, and interparticle forces. The experimentally measured packing configuration and inferred interparticle forces at different sample stresses were used to construct spring networks characterized by Hessian and damping matrices. The ultrasound responses of these network were simulated to investigate the origins of wave velocity, acoustic paths, dispersion, and attenuation. Results revealed that both packing structure and interparticle force heterogeneity played an important role in controlling wave velocity and dispersion, while packing structure alone quantitatively explained most of the observed wave attenuation. This research provides insight into time- and frequency-domain features of wave propagation in randomly packed granular materials, shedding light on the fundamental mechanisms controlling wave velocities, dispersion, and attenuation in such systems. Competing Interests: The authors declare no competing interest. (Copyright © 2020 the Author(s). Published by PNAS.) |
| Databáze: | MEDLINE |
| Externí odkaz: |
|