Abstract
Granular materials can fail through spontaneous events like earthquakes or brittle fracture. However, measurements and analytic models which forecast failure in this class of materials, while of both fundamental and practical interest, remain elusive. Materials including numerical packings of spheres, colloidal glasses, and granular materials have been known to develop an excess of low-frequency vibrational modes as the confining pressure is reduced. Here, we report experiments on sheared granular materials in which we monitor the evolving density of excited modes via passive monitoring of acoustic emissions. We observe a broadening of the distribution of excited modes coincident with both bulk and local plasticity, and evolution in the shape of the distribution before and after bulk failure. These results provide a new interpretation of the changing state of the material on its approach to stick-slip failure.
- Received 25 July 2017
- Revised 13 March 2018
DOI:https://doi.org/10.1103/PhysRevLett.120.218003
© 2018 American Physical Society
Physics Subject Headings (PhySH)
Focus
Precursor Sounds Warn of Imminent Slip
Published 25 May 2018
Distinctive sounds emanate from a material when it is stressed by an outside force and close to slipping—an effect that could lead to warnings of imminent material failure.
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