Sequential imperfect preventive maintenance policies

Improvement factors in hazard rate and age for a sequential preventative maintenance (PM) policy are introduced. Two imperfect PM models are analyzed: (1) PM reduces the hazard rate while it increases with the number of PMs, and (2) PM reduces the age. The PM is done at intervals x/sub k/ (k=1,2, . . . , N) and is imperfect. The optimal policies to minimize the mean cost rates are discussed. The optimal PM sequences (x/sub k/) are computed for a Weibull distribution. >