Reliability Equivalence Factors of a Series-Parallel System in Weibull Distribution

The performance of a reliability system can be improved by different methods, e.g. the reliability of one or more components can be improved, hot or cold redundant components can be added to the system. Sometimes these measures can be equivalent as they will have the same effect on some performance measure of the system. This paper discusses the reliability equivalences of a series-parallel system. The system considered here consists of m subsystems connected in parallel, with subsystem i consisting of ni independent and identical components in series for i=1, 2, ..., m. The failure rates of the system components are functions of time with a life distribution of Weibull distribution. Three different methods are used to improve the given system reliability. The reliability equivalence factor is obtained using the reliability function. The fractiles of the original and improved systems are also obtained. Numerical example is presented to interpret how to utilize the obtained results.