A cumulative damage shock model with imperfect preventive maintenance

In this article the authors consider a cumulative damage shock model under a periodic preventive maintenance (PM) policy. The PM is imperfect in the sense that each PM reduces the damage level by 100(1-b)% 0•b•1. A system suffers damage due to shocks and fails when the damage level exceeds some threshold. The authors derive a sufficient condition for the time to failure to have an IFR distribution. They also discuss the associated problem of finding the number of PM’s that minimizes the expected cost rate.