Research On Step-stress Accelerated Degradation Test Technology Of Electrical Conncceor

As a basic component, electrical connector is widely used in model system with large amounts and plays an important role. To satisfy the increasingly high requirements for war-readiness performances, the model system calls for32-year storage life of electric connector. As no relevant theory and method is available now to evaluate the reliability of this kind of long-life electrical connector, it is difficult to judge whether it is reliable enough to meet the requirements of the system within the given time limit for project. Therefore, it is quite necessary and significant to study how to evaluate the storage reliability of long-life electrical connector. In the background of the model system featuring long-term storage and one-shot application, the dissertation takes typical and widely used Y11X-1419electrical connector as the object, and focuses on the study on its performance change law in the storage environment, the accelerated degradation test technique for it and the reliability evaluation method based on accelerated degradation test data, thus providing a theoretical basis for the rapid evaluation on the storage reliability of electrical connector, and an effective support for the design and evaluation of the storage life of the model system.This dissertation is composed of eight chapters, and the main work of each chapter is specified as follows.Chapter one gives an introduction to the research background, the purpose and the significance of the dissertation. In this chapter, the domestic and foreign research status and the problems in relevant fields are analyzed in terms of reliability test technique, accelerated degradation test technique and the reliability research of electrical connectors. Besides, the problems in the evaluation on the storage reliability of long-life electrical connector are summarized, and the research approach and the main research content are proposed.In chapter two, the failure mechanism of electrical connector in the storage environment is studied based on their structure, functions and storage environment stresses. Besides, the accelerated degradation model is built according to the growth law of oxide film, and the life distribution model is built for electrical connector according to the electrical structural properties. In chapter three, an optimized design method is put forward for the step-stress accelerated degradation test plan for electrical connector. The traditional step-stress accelerated degradation test optimized plan, the optimal step-stress accelerated degradation test plan with two stress levels and the step-stress accelerated degradation compromise test plan for overall consideration of robustness and estimated accuracy of the test plan are presented. Meanwhile, the sensitivity to parameter misspecification is analyzed for the optimized compromise test plan.In chapter four, based on the Monte Carlo simulation, a simulated evaluation method is set up for the step-stress accelerated degradation test plan for electrical connector. From the perspectives of robustness and estimated accuracy of the reliability property value, the optimized plans for the step stress accelerated degradation test are evaluated, thus verifying the correctness of the optimized design theory for accelerated degradation test and the rationality of the final test plan.In chapter five, on the basis of the maximum likelihood estimation theory, the accelerated degradation model parameters of electrical connector are estimated with the step-stress accelerated degradation test data, and the storage reliability of electrical connector under normal stress level is evaluated.In chapter six, based on the accelerated degradation test data, the confidence interval estimation method is established for electrical connector. Using the two-step bias-correction method, on the basis of the Bootstrap bias-correction of the degradation model parameter estimation value, the confidence interval to the reliability of electrical connector is re-corrected, thus, the pointwise approximate Bootstrap confidence interval estimation to the reliability of electrical connector under normal stress is presented.In chapter seven, based on the step-stress accelerated degradation test data of electrical connector, a verification method is set up for the accelerated degradation model. The degradation path model, the degradation rate distribution hypothesis, the constant term hypothesis and the accelerated degradation equation are examined, thus verifying the accuracy of the accelerated degradation model deduced from the failure mechanism.Chapter eight gives a summary of the dissertation and some suggestions for further research work.