Migrating Shear Bands in Shaken Granular Matter
Jonathan E Kollmer1,2,3, Tara Shreve1,4, Joelle Claussen5
1Institute for Multiscale Simulation of Particulate Systems, Cauerstraße 3, 91058 Erlangen, Germany.
Physical Review Letters
|August 16, 2020
Summary
Sheared granular matter forms shear bands that migrate upward due to dilatancy. This phenomenon explains the periodic inflation and collapse observed in granular materials.
Area of Science:
- Physics
- Materials Science
- Geophysics
Background:
- Shearing dense granular matter often leads to strain localization in shear bands.
- Typically, these shear bands stabilize after an initial transient phase.
Purpose of the Study:
- To investigate a novel setup that generates periodically migrating shear bands.
- To elucidate the underlying physical mechanisms driving shear band migration.
- To connect migrating shear bands to previously observed material behaviors.
Main Methods:
- Development of a specialized experimental setup for creating periodic shear bands.
- Utilizing x-ray radiography for in-situ observation of shear band dynamics.
- Analysis of granular matter volume fraction changes during shearing.
Main Results:
- Demonstration of horizontally aligned shear bands migrating upward through the sample.
- Identification of dilatancy (reduction in volume fraction) as the cause of shear band migration.
- Correlation of migrating shear bands with periodic material inflation and collapse.
Conclusions:
- Dilatancy in sheared granular media can induce upward migration of shear bands.
- The observed shear band migration provides a mechanism for the cyclic volume changes in granular materials.
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