Reliability modelling for components with phased degradation and random shocks

Many electromechanical components are simultaneously subject to catastrophic failure and degradation failure. During the operation, these two failure modes are both competing and bilateral correlated. In addition, the degradation trajectory of component can be phased, and the degradation and shocks have twofold dependence, as nonfatal shocks will induce random additional damages to intrinsic degradation, and the tolerant capability of component to shock decreases over time. In this paper, a reliability model focused on the dependent-competing is derived, taking phased intrinsic degradation and shock-dependent decline of shock limit and mutual correlation between two failure modes into consideration. The implementation of proposed model is demonstrated with simulation.