Degradation process and lifetime evaluation of repairable and non-repairable systems subject to random shocks

This paper studies the degradation process of mechanical systems which are composed of multiple sub-systems which have been subjected to continuous wear and random shocks. We have developed a new mathematical model of series systems and established the function curve of each sub-system's degradation over time to evaluate the system's lifetime. Previous research mainly focused on simple non-repairable systems with multiple sub-systems which suffered from independent degradation processes, and held the view that systems can normally work only when the total degradation of each sub-system is less than the threshold level. This new model extends previous research by considering both a non-repairable system and a repairable system subject to multiple degradation processes, and these two types of systems will also fail when the degradation of the overall system is greater than the threshold level. The model is demonstrated on a specific example by means of Monte-Carlo simulation.