Reliability modeling method for dependent competing failure system

This paper studies a reliability analysis method for a system which experiences two dependent competing failure processes, including a random degradation process and a random shock process. Whether the soft failure or the hard failure take place, the system will fail. In our model, the arriving shocks can cause damage on degradation process, and the random shock process can be influenced by degradation process too. Thus, these two failure process are dependent. In present research on dependent competing failure, most academics consider that every shock can cause damage on the degradation. However, when shock loads are smaller than the tolerance of system, the shock process will not affect the degradation process. Taking this into consideration, we divide the random shocks into three “zones” according to their magnitudes, damage zone, fatal zone, and safety zone, based on different effects on the system's failure behavior. In addition, Monte Carlo simulation is used to estimate the system reliability. Finally, we use an application case to explain this method. The result shows that the model we proposed is capable to describe the reliability of a dependent competing failure system.