by Sofiane Gasmi, Ernie Love, Waltraud Kahle.
Series: 1998-39, Preprints
In this research we are concerned with the statistical
modelling of repairable systems when operating under following two phenomenon. A system
(machine) is observed to operate in one of two modes. The most common mode is loaded
(or regular) operation. Occasionally the system is placed in an unloaded state. In this
latter state, while the system is mechanically still operating, it is assumed that the
failure intensity is reduced due to this reduction in operating intensity. To capture this
potential reduction in failure intensity due to switching operating modes, a proportional
hazards framework is utilized. In either operating condition, maintenance records analyzed
indicated that the system was occasionally shut down and either a minor or major repair was
undertaken. Furthermore, despite such repairs it was observed that both modes of operation
(loaded or unloaded) resulted in failures. On failure, one of three actions were taken;
failures were minimally repaired, given a minor repair or given a major repair.
Both types of repairs are assumed to impact the intensity following a virtual age process
of the general form proposed by Kijima. The issue in this research is to develop a statistical
model of such an operating/maintenance environment.
repairable systems, imperfect virtual age repair processes, Likelihoodfunction, minimal repair, imperfect repair, Weibull-type intensities.