Stochastic analysis of preventive maintenance in heterogeneous populations

Many different types of preventive maintenance policy have been defined in the literature and implemented in reliability practice. However, almost all models, procedures, and approaches deal only with the case when items come from homogeneous populations. In this paper, we analyze the effect of preventive maintenance on the reliability characteristics of items selected from heterogeneous populations. We discuss a general definition of the conditional failure rate and apply it for describing the reliability of ‘heterogeneous items’ under preventive maintenance.