Modelling safety of multistate systems with ageing components

Basic notions of the ageing multistate systems safety analysis are introduced. The system components and the system multistate safety functions are defined. The mean values and variances of the multistate systems lifetimes in the safety state subsets and the mean values of their lifetimes in the particular safety states are defined. The multi-state system risk function and the moment of exceeding by the system the critical safety state are introduced. The exemplary safety structures of the multistate systems with ageing components are defined and their safety functions are determined. As a particular case, the safety functions of the considered multistate systems composed of components having exponential safety functions are determined. Applications of the proposed multistate system safety models to the evaluation and prediction of the safty characteristics of the exemplary series, parallel, “m out of n”, consecutive “m out of n: F”, series-parallel, parallel-series and “m out of l”-series systems are presented as well.