Availability for repairable components and series systems

The failure pattern of repairable components is often modelled by an alternating renewal process which implies that a failed component is perfectly repaired. In practice, repair is often imperfect. This paper proposes a generalized availability model for repairable components and series systems. The lifetime of a repaired component has a general distribution which can be different from that of a new component. Availability and some asymptotic quantities in these models are derived. An example illustrates the application of these models