Step-stress Accelerated Degradation Test Modeling and Statistical Analysis Methods

In order to get a rapid assessment on the storage reliability of high-reliable and long-life products within the storage period,accelerated degradation test data with a large amount of reliability information of product is adopted.Conducting a constant-stress accelerated degradation test(CSADT)is generally very costly as it requires a large sample size and long time for test.To overcome this problem,it is necessary to carry out research on modeling and statistical analysis methods of step-stress accelerated degradation test(SSADT).Taking electrical connectors as the object,a research is conducted on statistical model and assessment method for SSADT.On the basis of mixed-effect degradation path model,the statistical model of SSADT for electrical connectors is presented,the maximum likelihood method for SSADT data based on mixed-effect degradation model is proposed.SSADT accelerated by temperature stress is conducted to Y11X-1419 type of electrical connectors,and the storage reliability is assessed with the SSADT data.Compared with the result obtained from accelerated life test,the reliability estimation of 32-year storage period for electrical connectors obtained from SSADT data only have a difference of 0.869%,which validates the accuracy of the degradation model and the feasibility of the test data statistic analysis method put forward.