  The rheology of a 3-dimensional granular system consisting of frictional
elongated particles was investigated by means of discrete element model (DEM)
calculations. A homogenous shear flow of frictional spherocyliders was
simulated, and a number of rheological quantities were calculated. In the
framework of the $\mu(I)$ rheology, the effective friction was found to be a
non-monotonic function of the aspect ratio for interparticle friction
coefficient $\mu_p \lesssim 0.4$, while it was an increasing function for
larger $\mu_p$. We reveal the microscopic origin of this peculiar non-monotonic
behavior. We show the non-trivial dependence of the velocity fluctuations on
the dissipation regime, and trace back the behavior of the normal stress
differences to particle-level quantities.
