Model for force fluctuations in bead packs.

摘要: We study theoretically the complex network of forces that is responsible for static structure and properties granular materials. present detailed calculations a model in which fluctuations force distribution arise because variations contact angles constraints imposed by balance on each bead pile. compare our results function this model, including exact certain angle probability distributions, with numerical simulations distributions random sphere packings. This reproduces many aspects observed both experiment Our closely related to some have been studied context self-organized criticality. evidence context, "critical" power-law occur only when parameter (hidden other interpretations) tuned. numerical, mean field, all indicate almost decays exponentially at large forces.