Study on Meso-Structure Evolution in Granular Matters Based on the Contact Loop Recognition and Determination...

Area of Science:

• Physics
• Materials Science
• Geomechanics

Background:

• Granular matter stability relies on contact loop evolution within its mesoscopic contact network.
• Understanding geometric shapes of contact loops is crucial for correlating meso-structure with macro-scale mechanical behavior.
• Existing methods struggle with the complexity and numerous geometric shapes of loops in contact networks.

Purpose of the Study:

• To develop a contact loop recognition and determination technique for complex granular matter networks.
• To investigate the evolution of meso-structural indexes alongside macro-mechanical indexes using numerical simulations.
• To establish models linking granular matter's meso-structure to its macro-mechanics.

Main Methods:

• Development of a novel Q-Y algorithm for contact loop recognition and geometric type determination.
• Numerical biaxial compression tests conducted using the discrete element method (DEM).
• Analysis of meso-structural indexes (loop number and area percentages) and macro-mechanical indexes (stress, strain).

Main Results:

• The Q-Y algorithm effectively identifies geometric types of contact loops from images.
• Contact loop evolution is most dynamic during the hardening stage, with opposing trends for L3 and L6+ loop number percentages.
• Only L6+ loop area percentage increases, while others decrease; meso-structural indexes correlate with macro-mechanical changes.

Conclusions:

• The Q-Y algorithm provides a robust method for analyzing granular contact networks.
• Meso-structural loop evolution, especially in the hardening stage, directly reflects macro-mechanical responses.
• Established multivariate models successfully bridge the gap between granular meso-structure and macro-mechanics.