This study presents a reliability and availability analysis of human-machine systems with human errors and common-cause failures. The systems incorporate elements of several commonly used redundant configurations: standby, k-out-of-n, majority voting with imperfect voter, and parallel. The analysis considers systems with constant human error rates, increasing human error rates and general human error rates, and with arbitrarily distributed failed system repair times. The method of linear ordinary differential equations for general system failure rates is presented to obtain the general expressions of the steady state availability for various types of system repair time distributions, such as Gamma, Weibull, lognormal, exponential and Rayleigh distributions. A method which combines the inclusion supplementary variables technique and the method of stages is developed to perform time-dependent system availability analysis for systems with both time-dependent human error rates and failed system repair rates. Generalized expressions for such relevant system performance indices as the system reliability, steady state availability, time-dependent system availability, mean time to failure and system variance of time to failure are presented. The impact of human error, common-cause failure, failed system repair policy and the elements of redundant configurations on the values of the afore-said system performance indices is demonstrated by means of plots.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/10036 |
| Date | January 1995 |
| Creators | Yang, Nianfu. |
| Contributors | Dhillon, Balbir, |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 364 p. |
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