The general substitution model, states that the failure time of a repairable system is an unspecified random variable. The duration of corrective maintenance (perfect) is also a random variable. In this model it is assumed that preventive maintenance is not performed.
Let’s denote by Ti the duration of the i−th interval of operation of the repairable system. For the assumption of perfect maintenance (as good as new), {T1,T2,…,Ti,…,Tn} is a sequence of independent and identically distributed random variables.
Let us now designate with Di the duration of the i−th corrective maintenance action and assume that these random variables are independent and identically distributed. Therefore, each cycle (whether it is an operating cycle or a corrective maintenance action) has an identical probabilistic behavior, and the completion of a maintenance action coincides with time when system state returns operating
Regardless of the probability distributions governing Ti and Di, the fundamental result of the general pattern of substitution is as follows:
|
|
- 1083 reads
