  We analyze the isotropic compaction of assemblies composed of soft pentagons
interacting through classical Coulomb friction via numerical simulations. The
effect of the initial particle shape is discussed by comparing packings of
pentagons with packings of soft circular particles. We characterize the
evolution of the packing fraction, the elastic modulus, and the microstructure
(particle rearrangement, connectivity, contact force and particle stress
distributions) as a function of the applied stresses. Both systems behave
similarly; the packing fraction increases and tends asymptotically to a maximum
value $\phi_{max}$, where the bulk modulus diverges. At the microscopic scale
we show that particle rearrangements occur even beyond the jammed state, the
mean coordination increases as a square root of the packing fraction and, the
force and stress distributions become more homogeneous as the packing fraction
increases. Soft pentagons present larger particle rearrangements than circular
ones, and such behavior decreases proportionally to the friction.
Interestingly, the friction between particles also contributes to a better
homogenization of the contact force network in both systems. From the
expression of the granular stress tensor, we develop a model that describes the
compaction behavior as a function of the applied pressure, the Young modulus
and the initial shape of the particles. This model, settled on the joint
evolution of the particle connectivity and the contact stress, provides
outstanding predictions from the jamming point up to very high densities.
