Markov model, aging factor, multi-state system, universal generating function
Abstract
With the increasing of service years, failure happens more frequently than before, which is consistent with the failure rate of equipment during the wear-out life period. On the base of continuous time Markov model for multi-state elements during the useful life period, aging factor is introduced to establish a non-homogenous continuous time Markov model during the wear-out life period. To obtain the reliability of a multi-state element, universal generating function is applied to combine its performance levels and probability functions. Through a combination operator determined by series-parallel logic relations, universal generating function of a multi-state system can be obtained. At last, a compressor of an engine is taken for example. The reliability of the system and its elements considering aging factor are relatively lower than that during the useful life period. And to maintain a reliability level at 80% under the demand of 50%, two days will be reduced from the planned maintenance cycle.