双指标阶段性退化建模及可靠性分析

High reliability and long life products often need to meet multiple functions at the same time, and the degradation mechanism is complex. The problem of multi-index and multi-stage in the process of performance degradation is becoming more and more prominent. Therefore, considering the stage characteristics of degradation process and the coupling law between indexes in different stages, a two index stage degradation model and reliability analysis method are established based on Copula function and Wiener process. At the same time, aiming at the general situation that the change points of two indexes are not in the same position in the process of product degradation, a global estimation method of model parameters considering two index change points is proposed. Finally, the applicability and effectiveness of the proposed method are verified by the comparative analysis of an example of cabin door lock. The results show that the proposed simultaneous interpreting method can more accurately describe the correlation and stage rules of degradation process compared with the traditional dual index model, and the reliability evaluation results obtained are more reasonable and effective.