A coefficient of restitution of rock materials

At a macroscopic scale, even a purely elastic contact between rock particles is accompanied by energy dissipation. The resulting hysteretic loop of the stress/strain path during such a loading and unloading event suggests that grains recover slower to their original shape than when they were first deformed. This contact behaviour may be simulated in distinct element codes by utilizing a hysteretic damping contact model. In this research, values for the elastic coefficient of restitution for components of a molasse conglomerate were measured using a newly developed drop-test apparatus. These values can be used to calibrate or to verify constitutive models that incorporate strain-rate-independent, elastic hysteretic damping.