Plastic flow and localization in an amorphous material: Experimental interpretation of the fluidity

Area of Science:

• Solid Mechanics
• Materials Science
• Rheology

Background:

• Granular materials exhibit complex plastic responses under applied stress.
• Understanding the evolution of plastic fields is crucial for predicting material behavior.

Purpose of the Study:

• To experimentally investigate the evolution of the plastic field in granular materials during progressive loading.
• To analyze the heterogeneity and fluctuations of the plastic field in response to incremental strain.

Main Methods:

• Experimental analysis of granular material under progressive loading.
• Decomposition of the plastic field into distinct components based on strain increment scales.

Main Results:

• The plastic field transitions from homogeneous to heterogeneous with increasing load.
• The plastic field exhibits two components that evolve independently on different strain increment scales.
• A slowly varying component of the plastic field aligns with the fluidity field concept.
• The fluidity field concentrates along a macroscopic direction defined by the Mohr-Coulomb angle.

Conclusions:

• The plastic response of granular materials is characterized by a two-component evolution.
• The fluidity field plays a significant role in the rheological behavior of amorphous materials, including granular ones.
• The Mohr-Coulomb angle dictates the macroscopic direction of plastic flow concentration.