A load-capacity interference model for common-mode failures in 1-out-of-2: G systems

Load-capacity (stress-strength) interference theory is used to model the time-dependent behavior of a 1-out-of-2: G redundant system and to examine common-mode failures. For single units subjected to Poisson distributed load arrivals, the random failures, infant mortality, and aging are associated with load variability, capacity variability, and capacity deterioration, respectively. This paper extends the analysis to a redundant system by using a Markov model to treat Poisson distributed loads arriving at units simultaneously. Loss of s-independence of the unit failures is analyzed with joint PDFs of load and capacity. In the rare-event approximation, the degree of redundancy loss is characterized by expressing the coefficient in the beta-factor method in terms of the load and capacity distributions.