Stress-Strain Relations and Vibrations of a Granular Medium

TLDR

The study investigates stress‑strain behavior in a granular medium modeled as a face‑centered cubic array of elastic spheres. The authors derive a contact‑force based stress‑strain relation and test it by measuring wave velocities and energy dissipation in granular bars composed of face‑centered cubic arrays of spheres. Experiments confirm the predicted wave velocities but show that energy dissipation scales with the square of the maximum tangential contact force, contrary to the cubic scaling predicted for small amplitudes.

Abstract

Abstract A differential stress-strain relation is derived for a medium composed of a face-centered cubic array of elastic spheres in contact. The stress-strain relation is based on the theory of elastic bodies in contact, and includes the effects of both normal and tangential components of contact forces. A description is given of an experiment performed as a test of the contact theories and the differential stress-strain relation derived from them. The experiment consists of a determination of wave velocities and the accompanying rates of energy dissipation in granular bars composed of face-centered cubic arrays of spheres. Experimental results indicate a close agreement between the theoretical and experimental values of wave velocity. However, as in previous experiments with single contacts, the rate of energy dissipation is found to be proportional to the square of the maximum tangential contact force rather than to the cube, as predicted by the theory for small amplitudes.