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Updated: May 8, 2025
06:07
Studying Large Amplitude Oscillatory Shear Response of Soft Materials
Published on: April 25, 2019
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Anomalous Softness in Amorphous Matter in the Reversible Plastic Regime
A Elgailani1, D Vandembroucq2, C E Maloney1
1Northeastern University, Department of Mechanical and Industrial Engineering, Boston, Massachusetts 02115, USA.
Physical Review Letters
|April 25, 2025
Summary
Amorphous solids subjected to cyclic shear strain exhibit a surprising result: lower energy states, achieved at higher strain amplitudes, are mechanically softer. This challenges conventional understanding of energy and mechanical response in these materials.
Area of Science:
- Condensed matter physics
- Materials science
- Rheology
Background:
- Amorphous solids exhibit complex mechanical behavior under cyclic loading.
- The reversible-plastic regime is characterized by hysteretic limit cycles.
- Understanding the relationship between energy and mechanical response is crucial for material design.
Purpose of the Study:
- To investigate the mechanical properties of amorphous solids in the reversible-plastic regime.
- To explore the relationship between ground state energy and mechanical softness.
- To explain the observed anomaly using theoretical models.
Main Methods:
- Simulations of an elastoplastic model of amorphous solids.
- Application of athermal quasistatic cyclic shear strain.
- Analysis using Eshelby inclusion theory.
Main Results:
- Ground state energy decreases with increasing cycling amplitude.
- Lower energy states, cycled at higher amplitudes, are mechanically softer.
- Plastic rearrangements initiate at smaller stresses and strains in lower energy states.
Conclusions:
- The study reveals an inverse relationship between energy and mechanical softness in cyclically sheared amorphous solids.
- Eshelby inclusion theory provides a quantitative explanation for this counterintuitive observation.
- Findings guide experimental and simulation studies on amorphous solids.
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