Dense granular media is prevalent in a myriad of applications ranging from soil reinforcement in construction to manufacturing in the pharmaceutical industry. When compressed, two subnetworks with different loading characteristics are formed: a strong network, which is made up of force chains consisting of highly-loaded particles, and a weak network consisting of clusters of particles that are nominally-loaded. The propensity for a force chain to buckle is strongly influenced by particle packing and constraints provided by neighboring particles [1]. Unfortunately, existing continuum models do not commonly consider the mesoscale interactions between the strong and weak networks [2]. Therefore, we develop a micromechanics model that connects microscale force-chain mechanics to macroscale mechanical response. We first study the elastic behavior of a spring model to explicitly capture micro-scale force-chains. Using this spring model, we construct an equivalent inclusion problem, treating the strong network as inclusions and the weak network as the matrix. Through the lens of force-chain mechanics, this analytical model lets us examine the effects of fabric and mesoscale interactions on the macroscopic mechanical response. We present our calibration and validation methods, demonstrating the model’s predictive abilities. This investigation will show the importance of mesoscale network interactions on deviatoric stiffness.
References:
[1] Tordesillas, A., & Muthuswamy, M. (2009). On the modeling of confined buckling of force chains. Journal of the Mechanics and Physics of Solids, 57(4), 706-727.
[2] S. Luding, Micro–macro transition for anisotropic, frictional granular packings, In-
ternational Journal of Solids and Structures 41 (21) (2004) 5821–5836