A New Efficient Reliability Analysis Method for Competing Failure Systems

ABSTRACT In real‐world systems, component failures can be categorized into local failures (LF) and propagated failures (PFs). The PFs from components not only cause their own malfunction but also affect other components within the systems. However, in systems with functional dependence behavior, if a component (referred to as trigger component) fails before the PFs of components (referred to as dependent components) happen, it can isolate the PFs, thus preventing PFs from affecting other components; otherwise, the failure propagation effect occurs, causing extensive damage to the entire system. The competition between failure propagation and isolation shows a significant challenge in analyzing the reliability of the systems. This paper proposes an efficient combinatorial method based on binary decision diagram (BDD), referred to as BDD reuse method, for the reliability analysis of systems subject to competing failures. Compared to the traditional methods of generating multiple reduced fault trees and BDDs, this method generates only one fault tree and one BDD. An intelligent ward call system example is provided to demonstrate the application of the proposed method. The accuracy of the method is proved by Monte Carlo simulation. The performance is analyzed and compared with the traditional methods. In addition, the variable ordering strategy is studied, and a BDD reduction and evaluation method is proposed to further improve the efficiency of the method.