Research On Methods And Applications Of Accelerated Degradation Testing For Multiple Degradation System

Accelerated degradation testing (ADT) technology have a wide range of applications for reliability assessment and life prediction of so call"high reliability and long life"products with the advantages of short time-consuming, low expenditure and strong power of prediction. In real applications, some products may belong to multiple degradation system (MDS), which is referred to a product existing more than one degradation path, and each degradation path is affect to failure of this kind of products. Relevant researches on methods and applications of ADT usually analyze these degradation paths separately, and skip correlative of degradation paths, which cannot get the proper results, because the analysis process is drift from the real circumstances. Aiming at this problem, methods and applications of ADT for MDS are researched in this dissertation, by considering correlative of degradation paths, which provides technical support for life prediction of complex products. The main contributions are summarized as follows:(1) Analysis of degradation failure of MDS is carried out systematically, by probing into correlative of degradation paths by joint failure, subordinate failure, and so on. And then degradation path models, degradation distribution models, and acceleration models are established for ADT of MDS.(2) Methods of ADT based on multiple performance parameters are proposed, by introducing joint distributions to consider correlative of degradation paths. Simulation turns out that reliability assessment result is more accurate by the proposed methods, since which can reflect the real process of degradation paths in products.(3) Applications research is carried out in some roll-control board of××equipment. First of all, prior information, such as key performance parameters and the limit of stress, is obtained by failure mechanism and effect analysis and pre-test analysis. And then plan of ADT of roll-control board is designed, by considering those prior information.(4) Analysis methods of this dissertation are applied to life prediction for some roll-control board. Results turn out that, the system reliability is underestimated under the assumption that correlations among performance paths are independent. On the contrary, the proposed methods consider the correlations and lead to a more accurate result, which proving the availability and collection of the methods.In summary, this dissertation carries systematically research on correlative of degradation paths in MDS, and proposed methods on ADT of MDS, by theoretical analysis, simulation and application. The research results are meaningful for applying the ADT to reliability assessment and life prediction of complex products.