RELIABILITY AND MTTF PREDICTION OF K-OUT-OF-N COMPLEX-SYSTEMS WITH COMPONENTS SUBJECTED TO MULTIPLE STAGES OF DEGRADATION

In some environments the components may not fail fully but can degrade , and there may be multiple stages of degradation. In such cases, the efficiency of the system may decrease. In this study we present a mode l for predicting the reliability of k-out-of-n:G systems assuming that components are subjected to several stages of degradation as well as catastrophic failures. In the analysis we consider the state-dependent transition rates far the catastrophic failures and degradation proces ses. We also present the expressions to determine the reliability and mean time to failure (MTTF) of the k-out-of-n systems. Reliability and MTTF expressions for a special case of the model without catastrophic failures are also presented. Several numerical examples are given to illustrate the results.