The impacts of common cause failures for two-unit parallel systems from RAMS+C point of view

Common cause failures usually occurred in redundant systems in which the units or components are either identical or sharing the same power supply. Earlier research aim to improve reliability, availability and maintenance (RAM) of safety-related equipments by establishing optimal testing schedules for those systems. However, frequency maintenance tasks may not only induce unexpected failure due to inappropriate maintenance, but also increase the maintenance cost. Cost-effective preventive maintenance model for the equipments were provided to maintenance equipment availability with minimal cost. In this study, the impacts of common cause failures (CCF) on the testing schedule and average maintenance cost are provided.