Remaining useful life estimation under degradation and shock damage

This article presents a prognostic approach to estimate remaining useful life for systems subjected to dependent competing failure processes. In the literature, shock damage is the damage to a soft failure process caused by a shock process. However, how the degradation process causes damage to a hard failure process has not been well studied. In this article, the degradation damage is modeled as the damage to a hard failure process from a degradation process. Degradation and shock processes, as ‘‘elemental processes,’’ result in failures via either a soft failure or a hard failure process, namely, ‘‘compound processes.’’ Instead of leading to a direct failure, elemental processes construct compound processes: the soft failure process consists of a degradation process and shock damage, and the hard failure process consists of a shock process and degradation damage. In this way, the damage in this article especially represents the effect of an elemental process on other compound processes. Furthermore, a particle filter is applied based on the established model for system statement estimation and on-line prediction of remaining useful life distribution with and without measurement noise in prognostics. Finally, a numerical example is presented with sensitivity analysis.