Remaining useful life estimation for two-phase nonlinear degradation processes

Abstract

Owing to state transformation, operation switching, and degradation mechanisms, the processes of some deteriorating products often exhibit multiphase features. Unlike the traditional single-phase degradation model, the multiphase degradation model must consider the change-point variability and the associated degradation state. Therefore, degradation modeling and remaining useful life (RUL) estimation of the multiphase nonlinear deteriorating system is more challenging. With this consideration, we formulated two multiphase nonlinear degradation models based on the widely used nonlinear Wiener process-based model. Then, by modeling the uncertainty of the degradation state at the change-point, we obtained the exact analytical solutions for the lifetime and RUL estimation based on the two-phase model under the concept of the first passage time. Furthermore, we extended the results of the two-phase model to a multiphase model, and then provided an iterative method for lifetime and RUL estimations. Finally, we presented numerical and practical examples to verify the feasibility of the proposed method.