  A fiber bundle model in $(1+1)$-dimensions for the breaking of fibrous
composite matrix is introduced. The model consists of $N$ parallel fibers fixed
in two plates. When one of the plates is pulled in the direction parallel to
the fibers, these can be broken with a probability that depends on their
elastic energy. The mechanism of rupture is simulated by the breaking of
neighbouring fibers that can generate random cracks spreading up through the
system. Due to the simplicity of the model we have virtually no computational
limitation. The model is sensitive to external conditions as temperature and
traction time-rate. The energy {\it vs.} temperature behaviour, the diagrams of
stress {\it vs.} strain and the histograms of the frequency {\it vs.} size of
cracks are obtained. (to appear in Phys. Rev. B)
