Reliability Analysis of Two-Stage Nonlinear Phase-Dependent Wiener Degradation Process

Accurately assessing reliability and predicting the life of products is an important part of Prediction and Prognostics and Health Management. According to historical degradation data of products, the degradation model of two-stage nonlinear phase-dependent Wiener process is proposed to evaluate the dependability and forecast the lifetime of individual products. Firstly, a two-stage phase-dependent degradation model based on a nonlinear Wiener process was developed to characterize nonlinear nature of the degradation of product performance by simultaneously taking the correlation of degradation stages and the degradation heterogeneity of products into account; Secondly, the model parameters are estimated using EM algorithm based on historical degradation data of products; Finally, simulation studies are used to demonstrate the superiority of the approach for assessing offline reliability, and the validity of the method proposed in this paper is verified through an example of high-voltage pulse capacitors. The results show that compared with the degradation model based on phase-independent nonlinear Wiener processes, the two-stage nonlinear phase-dependent Wiener process degradation model can better capture actual degradation paths of products and provide a more reasonable assessment of lifetime reliability of products.