An application of a bathtub failure model to imperfectly repaired systems data

Abstract

AbstractIn this paper we use an exponential power distribution to develop a bathtub failure model for repairable systems. These results are compared with those using the more familiar Weibull distribution. The analysis is extended to three types of repair scenarios: good‐as‐new repairs (in which the repair following a failure completely refreshes the failure intensity), bad‐as‐old repairs (in which the repair has no effect on the failure intensity) and imperfect repairs (in which the failure intensity is only partially reset). We apply this analysis to hydro‐electric turbine data and find that an exponential power distribution produces a well‐defined bathtub failure model when used with an imperfect repair assumption. We furthermore find that this bathtub model produces an improved fit over the equivalent Weibull model.