Fabric-based jamming phase diagram for frictional granular materials

Area of Science:

• Physics
• Materials Science
• Engineering

Background:

• Granular materials exhibit distinct phases mapped by intensive properties like shear stress and density.
• Understanding the relationship between these phases and particle microstructure is crucial for predicting material behavior.

Purpose of the Study:

• To investigate the link between granular material phases and their fabric structure using simulations.
• To develop a novel jamming phase diagram based on microstructural properties.

Main Methods:

• Three-dimensional discrete element method (DEM) simulations of bi-disperse spherical frictional particles.
• Constant-volume quasi-static simple shear tests were performed on specimens with varying initial solid fractions.
• Analysis of fabric anisotropy (F) and coordination numbers (Z) of contact networks during shearing.

Main Results:

• A unique critical fabric surface (CFS) was identified in the F-Z space, independent of initial specimen conditions.
• The CFS correlates with jamming transitions, enabling phase distinction based on particle geometry.
• A new jamming phase diagram in the F-Z space was introduced.

Conclusions:

• Microstructure, specifically fabric and coordination, plays a critical role in the jamming phenomenon of granular materials.
• The proposed fabric-based jamming phase diagram provides a convenient method to identify granular material phases.
• This approach offers a new perspective for interpreting phase transitions under various loading conditions.