  We use computer simulations to study highly dense systems of granular
particles that are driven by oscillating forces. We implement different
dissipation mechanisms that are used to extract the injected energy. In
particular, the action of a simple local Stokes' drag is compared with
non-linear and history-dependent frictional forces that act either between
particle pairs or between particles and an external container wall. The Stokes'
drag leads to particle motion that is periodic with the driving force, even at
high densities around close packing where particles undergo frequent
collisions. With the introduction of inter-particle frictional forces this
"interacting absorbing state" is destroyed and particles start to diffuse
around. By reducing the density of the material we go through another
transition to a "non-interacting" absorbing state, where particles
independently follow the force-induced oscillations without collisions. In the
system with particle-wall frictional interactions this transition has signs of
a discontinuous phase transition. It is accompanied by a diverging relaxation
time, but not by a vanishing order parameter, which rather jumps to zero at the
transition.
