Combined k-out-of-n:G, and consecutive kc-out-of-n:G systems

Qualification tests for a system are normally carried out according to either a k-out-of-n:G scheme, or a consecutive k_c-out-of-n:G structure. The reliability of a combination of the two systems is evaluated, showing its benefit over each of the individual structures. As expected, the mean time to failure of the combined system is larger than any of them. Generalizations of the analysis are presented for tests with multi-state results, and for dependent tests. Illustrative numerical results are presented to substantiate the theory.