Availability and frequency of failures of a system in the presence of chance common-cause shock failures

The presence of common-cause shock failures in the reliability analysis of a system is discussed. The system reliability indices, namely the availability [A(t)] and frequency of failures are developed for a repairable system which is affected by chance common-cause shock (CCS) failures in addition to individual failures. The influence of CCS failures is emphasized in the reliability analysis. Formulae are developed for the above measures for a system when affected by individual failures as well as CCS failures. Also, these measures are compared for the case when CCS failures as well as individual failures are taken into account and that for individual failures alone. The numerical illustration of results is also discussed.