Criticality in creep experiments on cellular glass

Abstract

Creep experiments on cellular glass under a constant compressive load are monitored by acoustic emission. The statistical analysis of the acoustic signals emitted by the sample while stress is being internally redistributed shows that the distribution of amplitudes follows a power law, $N(A)\ensuremath{\sim}{A}^{\ensuremath{-}\ensuremath{\beta}}$, with $\ensuremath{\beta}=2.0$ independent of the load. Similarly, the interarrival times between two recorded events are also distributed via a power law, ${\ensuremath{\tau}}^{\ensuremath{-}\ensuremath{\gamma}},$ where \ensuremath{\gamma}=1.3. Finally, the distribution of the spatial distance between two consecutive events also shows scale invariance, $\ensuremath{\rho}(r)\ensuremath{\sim}{r}^{\ensuremath{-}\ensuremath{\pi}}$ with, under additional assumptions, $\ensuremath{\pi}=1.6$.