Research On Degradation Test Methods Of Products With A Long Lifetime

In recent years, reliability assessment test method based on performance degradation is a new research direction in the field of reliability test. It can effectively predict the lifetime of products with high reliability and long lifetime. With the development of the technology and engineering, the failure mechanism of products is becoming more and more complex. For many products with high reliability and long lifetime, their failure life data can not be obtained from the censoring life test or the accelerated life test. So many researchers try to extract the life information from performance degradation data to offset the lack of information in the reliability assessment of products with high reliability and long lifetime. However, with the rapid progress in the technology and manufacturing, many existed degradation test methods can not meet the needs that assess the reliability of products with high reliability and long lifetime. To solve the problem, this dissertation studies degradation test methods of products with high reliability and long lifetime. Based on the correlative theories, we propose some improved test methods and apply them in practice. The main achievements of the dissertation are as follows.(1) Conventional reliability assessment test methods are discussed. Two types of conventional reliability assessment test methods are explicitly introduced, including life test and degradation test. Then we compare the test design methods of the censoring life test, the accelerated life test, the normal-stress degradation test and the accelerated degradation test, and summarize their advantages and disadvantages. According to these conclusions, we propose some effective methods to improve the existed degradation tests, which are the theoretical basics of the dissertation.(2) Degradation test method using reduced sample is presented. To effectively obtain performance degradation data and check the consistency of the data, we present a new reliability assessment test method based on performance degradation which is called degradation test method using reduced sample. Using the reliability assessment of metallized film pulse capacitors, we explicitly introduce the methods of test design, data collection and data consistency check. At last, we apply the degradation test method using reduced sample to a case study, and show the validity of the test method.(3) Accelerated degradation test method with validation information is proposed. To validate reliability model, we propose a new reliability assessment test method based on performance degradation which is called accelerated degradation test method with validation information. Using the reliability assessment of metallized film pulse capacitors, we detailedly investigate the methods of test design, data collection and model validation. At last, we apply the accelerated degradation test method with validation information to a case study. Based on the results, we summarize the advantages and disadvantages of the test method.