  We propose a generic model to describe the mechanical response and failure of
systems which undergo a series of stick-slip events when subjected to an
external load. We model the system as a bundle of fibers, where single fibers
can gradually increase their relaxed length with a stick-slip mechanism
activated by the increasing load. We determine the constitutive equation of the
system and show by analytical calculations that on the macro-scale a plastic
response emerges followed by a hardening or softening regime. Releasing the
load, an irreversible permanent deformation occurs which depends on the
properties of sliding events. For quenched and annealed disorder of the failure
thresholds the same qualitative behavior is found, however, in the annealed
case the plastic regime is more pronounced.
