  The mechanical properties of metal matrix fiber-reinforced composites depend
on many aspects of their structure in a complicated way. In this paper, we
propose a \emph{minimalistic} approach to study interface debonding, matrix
cracking, and their competition in metal matrix fiber-reinforced elastoplastic
composites by numerical simulation. This approach combines a cohesive zone
model for interface debonding and a phase field model for matrix cracking. The
features of this framework are: (1) crack nucleation, propagation, and
branching can be easily tracked without the need of geometric programming; (2)
the interface debonding is determined merely by the CZM, but not interfered by
the phase field in the bulk; (3) the cohesive interface has zero thickness
instead of being regularized; (4) any reasonable cohesive law of interest is
readily incorporated with very few constraints; (5) elastoplasticity of the
matrix is conveniently taken into account, as strains in the model are all well
defined; (6) the competition of the two failure mechanisms, namely, matrix
cracking and interface debonding, is accurately captured. Accuracy of this
framework is verified with existing analytical and numerical results. The
proposed framework shows a potential in investigating various complicated crack
behaviors in composites.
