We perform a stick-slip experiment to characterize avalanches for granular materials. In our experiment, a
constant speed stage pulls a slider which rests on a vertical bed of circular photoelastic particles in a 2D
system. The stage is connected to the slider by a spring. We measure the force on the spring by a force
sensor attached to the spring. We study the PDF of energy release and slip size, avalanche shape in time, and other seismicity laws during slip avalanches. We analyze the power spectrum of the force signal
and probability distributions to understand the effect of the loading speed and of the spring stiffness on
the statistical behavior of the system. From a more local point of view and by using a high speed camera
and the photoelastic properties of our particles, we characterize the local stress change and flow of
particles during avalanches. By image processing we detect the avalanches, as connected components
in space and time, and the energy dissipation inside the granular medium and their PDFs. The PDFs of
avalanches obey power laws both at global and local scales, but with different exponents. We try to
understand the distribution and correlation of local avalanches in space and the way they coarse grain to
the global avalanches.
11:10 – 12:00 Contributed talks: Aghil Abed Zadeh, Duke University.
Authors: Aghil Abed Zadeh, Jonathan Barés, Robert Behringer
https://mediaspace.gatech.edu/media/Perry++Ellis+-+AZadeh_SMF_20180420/1_cerfiy5s