Reliability analysis of heterogeneous redundant systems with common cause failure using an enhanced goal-oriented methodology

This paper addresses the reliability analysis of multivariate heterogeneous redundant systems subject to common cause failure (CCF). Traditional CCF models typically rely on homogeneous assumptions and time-invariant failure mechanisms, which limit their applicability to complex software-intensive systems. To overcome these limitations, an enhanced goal-oriented (GO) methodology is developed by modelling CCF as the interaction between continuous performance degradation and random external shocks. The proposed framework integrates stochastic degradation processes and Poisson-driven shock models with predefined failure thresholds to quantify time-varying CCF probabilities in heterogeneous redundant structures. The method is applied to a radio heliograph system to demonstrate its effectiveness. Comparative results show that neglecting CCF leads to overestimation of system reliability, while the proposed approach provides a more realistic and accurate assessment. The framework extends the applicability of GO-based reliability analysis to complex systems with heterogeneous components and dynamic failure mechanisms.