  In this paper a multi-component system is studied where each component can be
repaired within the system. We consider that each component is subject to two
dependent competing failure processes due to degradation and random shocks and
each shock increases the total degradation of each component. For systems with
individual repairable components, each failed component can be replaced at any
inspection time and other components continue functioning, so the age of each
component at any inspection time is different from other components. Different
initial ages have an effect on the optimal time that the whole system should be
inspected, therefore the optimal inspection time should be calculated
dynamically considering the age of each component at the beginning of the
interval. In this paper, the system reliability and cost rate function is
calculated for a system with individually repairable components considering
random age for each component. Two numerical examples demonstrate the proposed
reliability and maintenance model.
