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Volume-shear coupling in a mesoscopic model of amorphous materials
1Centro Atómico Bariloche, Instituto Balseiro, Comisión Nacional de Energía Atómica, CNEA, CONICET, UNCUYO, Av. E. Bustillo 9500 (R8402AGP) San Carlos de Bariloche, Río Negro, Argentina.
Physical Review. E
|August 17, 2022
Summary
This study introduces a new model for yield stress materials, revealing that volume fluctuations coupled with shear reduce material strength. This model explains key phenomena like volume increase with deformation rate and altered shear band orientation.
Area of Science:
- Materials Science
- Rheology
- Condensed Matter Physics
Background:
- Yield stress materials exhibit complex mechanical behaviors under deformation.
- Understanding shear banding and volume changes is crucial for material characterization.
- Existing models often simplify the interplay between shear and local density.
Purpose of the Study:
- To develop a two-dimensional mesoscopic model for yield stress materials.
- To investigate the coupling between local volume fluctuations and shear.
- To analyze how this coupling affects material strength and deformation characteristics.
Main Methods:
- Development of a novel two-dimensional mesoscopic model.
- Incorporation of local volume fluctuations coupled to shear.
- Analysis of shear strength dependence on local density variations.
Main Results:
- The model demonstrates that decreased local density leads to reduced shear strength.
- Observed phenomena include volume increase with deformation rate and altered shear band orientation (deviating from 45°).
- Homogeneous deformation instability occurs at low deformation rates when volume-shear coupling is significant.
Conclusions:
- The proposed model successfully reproduces known phenomenological effects in yield stress materials.
- Volume-shear coupling is a critical factor influencing material response and stability.
- Findings offer insights into shear bands in metallic glasses and other out-of-equilibrium systems.
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