  The paper constructs a coarse-grained model to investigate dry sliding
friction of the body-centered-cubic Fe micron-scale system by smoothed particle
hydrodynamics simulations and examines influences of the spring force on the
characters of friction. The N_atom = 864 \times 10^12 atoms Fe system is
coarse-grained into the two different simple-cubic particle systems, one of
432000 and the other of 16000 particles. From the detection of stick-slip
motion, friction coefficient, dependence of friction coefficient on isotropy or
anisotropy of the spring force and externally applied normal load, we find that
the coarse-grained model is a reasonable modeling process for study of friction
of the Fe system and the anisotropic behavior presents better friction of the
system than the isotropic one.
