Research On Reliability Technology Of High-reliability And Long-lifetime Products

With the development of science and technology, the increasing improvement of manufacture techniques, the high-reliability & long-lifetime products are commonly used in such fields as Military, Astronautics & Aeronautics, Electronic industries and Communications. The problem of how to enhance their reliability and forecast their lifetime have become an important question deserving an in-depth study. This dissertation mainly carries on a systemic research on the key technologies and methods of high-reliability & long-lifetime products' reliability engineering, include reliability modeling analysis, reliability assessment and reliability growth. The main contributions of this dissertation are summarized as follows:1. Based on traditional reliability analysis methods, the degradation failure modes of high-reliability & long-lifetime products are investigated, the reliability modeling analysis method based on competing mode of hard and soft failure is presented. The relations between reliability, failure rate, MTBF and failure threshold are analyzed by this method. The results reveal that this modeling analysis method adheres to the rules of products' failure, and can help to optimize product reliability design.2. The characteristics of performance degradation data are analyzed. Based on statistical analysis methods for life test data, the reliability assessment methods with performance degradation data based on pseud-failure lifetime is presented. The disciplinarians of product performance degradation data with time are analyzed, the reliability assessment methods with performance degradation data based on performance degradation distribution is presented. These methods of reliability assessment are respectively applied to evaluating reliability of GaAs lasers. The application shows that performance degradation data contain abundant product reliability information, the reliability and lifetime of the high-reliability & long-lifetime products can be evaluated with performance degradation data availably, even if the failure time cannot be obtained by life testing(LT) or accelerated life testing(ALT).3. The characteristics of accelerated degradation data are analyzed, and the accelerative condition and common accelerated equations of accelerated degradation process are summarized. Introducing accelerated equations into analysis of accelerated degradation testing(ADT) data, the reliability assessment methods with accelerated degradation data based on pseud-failure lifetime is presented, and the reliability assessment methods with accelerated degradation data based on performance degradation distribution is presented. These methods based on ADT data are respectively applied to evaluating reliability of carbon-film resistors. The application shows that the ADT methods can be applied to evaluate reliability and forecast lifetime even when the performance degradation process of high-reliability & long-lifetime product is quite slow. 4. The key technologies of reliability growth methods based on reliability enhancement testing(RET) are studied, the principles of RET's profiles and the steps of RET are summarized. The method that utilizes traditional test equipments to accomplish partial content of RET is presented. The RET methods are applied to××satellite payload, and the test results are carefully analyzed, the methods of improving on this product's design are presented. The test results indicate that RET can effectively stimulate potential defaults of typical high-reliability & long-lifetime products such as××satellite payload, and RET is an effective method which can improve reliability of high-reliability & long-lifetime products quickly.In summary, the dissertation has deepened the understanding of failure process of high-reliability & long-lifetime products by theory analysis and resolved the questions of how to analyze their reliability, assess their reliability, forecast their lifetime, enhancement their reliability. These research results are meaningful for the application of reliability assurance and lifetime forecast of high-reliability & long-lifetime products.