  Dense granular systems subjected to an imposed shear stress undergo
stick-slip dynamics with systematic patterns of dilation-compaction. During
each stick phase, as the frictional strength builds up, the granular system
dilates to accommodate shear strain, developing stronger force networks. During
each slip event, when the stored energy is released, particles experience large
rearrangements and the granular network can significantly change. Here, we use
numerical simulations of 3D, sheared frictional packings to show that the mean
betweenness centrality -- a property of network of interparticle connections --
follows consistent patterns during the stick-slip dynamics, showing sharp
spikes at each slip event. We identify the source of this behavior as arising
from the connectivity and contact arrangements of granular network during
dilation-compaction cycles, and find that a lower potential for connection
between particles leads to an increase of mean betweenness centrality in the
system. Furthermore, we show that at high confinements, few particles lose
contact during slip events, leading to a smaller change in granular
connectivity and betweenness centrality.
