Measuring and upscaling micromechanical interactions in a cohesive granular material

Area of Science:

• Materials Science
• Mechanical Engineering
• Physics

Background:

• Disordered heterogeneous materials exhibit complex mechanical properties due to multi-scale interactions.
• Predicting macroscopic behavior (stiffness, fracture) from local interactions is challenging.

Purpose of the Study:

• To investigate the mechanical properties of cohesive granular materials.
• To link microscopic characteristics to macroscopic observables.
• To develop a predictive model for disordered heterogeneous media.

Main Methods:

• Characterization of single polymer bridges under traction and shear using micropipette deflection.
• X-ray microtomography to analyze granular packing structure.
• Large-scale discrete element model (DEM) simulations informed by empirical measurements.

Main Results:

• Accurate prediction of aggregate mechanical responses, including compressive failure.
• Demonstration of how material stiffness relates to component stiffness and geometry.
• Successful correlation of microscopic bridge properties with macroscopic material behavior.

Conclusions:

• Microscopic characterization and DEM simulations can accurately predict the mechanical behavior of cohesive granular materials.
• This methodology offers new insights for understanding and predicting complex disordered materials.
• Applicable to materials like porous rock, snow, and foam.