Research On Space Environment Reliability Test And Evaluation Of Aerospace Electrical Connector

Space environment is the main reason inducing failure to space product in-orbit. Electrical connector is widely used in aerospace area with large amounts and plays an important role. As reliability requirements for spacecraft continue to improve, some communication satellites, such as DFH-4, require of the in-orbit life 15 years, which proposes an even higher requirement for space environment reliability of electrical connector.Currently, as China has not yet carried out systematic research on space environment reliability of electrical connector, there is not enough knowledge about degradation rule of performance parameters; the failure modes and mechanism are unclear; and there is lack of appropriate indicators for performance and reliability in space environment. In reliability design of spacecraft, the reliability analysis, design and selection of electrical connector is mainly base on experiences or foreign standards, which has become a bottleneck restricting the development of aerospace electrical connectors in China.In this dissertation, the application background is based on DFH-4. The widely used Y11P type of round low-frequency electrical connector is taken as the research object, as its structure and material is representative. The space environment effect of electrical connector is studied, and the reliability evaluation method, using simulation tests on ground to evaluate the space environment reliability, is researched. This research provides a theoretical foundation to rapidly assess reliability of electrical connector in space environment, and technical reserves to improve the system reliability design level for spacecraft.This dissertation is divided into eight chapters, and the main work of each chapter is as follows:In Chapter 1, the research background, purpose and significance are described. The historical investigations and existed problems in related field are analyzed from the following three aspects:reliability engineering, space environment reliability and the reliability of electrical connectors. Then, the idea and contents of this dissertation are proposed.In Chapter 2, the space environment effects and failure modes are analyzed comprehensively based on the structure, materials and functions of electrical connector and the stresses existing in-orbit. It provides a foundation to formulate a test method to simulate space environment on ground, and to research the space environment effects and reliability.In Chapter 3, on the base of space environment effects and failure modes and the existing simulation test techniques on ground, the simulation effects and feasibility of tests and the demands to carry out systematic research for mechanism are analyzed. The test method to simulate space environment on ground is formulated. It provides a general idea of test to research space environment effects and reliability of electrical connector systematically.In Chapter 4, on the base of the simulation test on ground and data analysis, the rules of insulation resistance and contact resistance varying with atmospheric pressure and temperature are determined. Then, the simulation test methods on ground and data analysis methods are formulated to research the performance characters of electrical connector in space environment.In Chapter 5, on the base of the simulation test on ground and data analysis, the rules of insulation resistance and contact resistance varying with time under the multiple stresses of vacuum-temperature-current-voltage are determined. The reasons that induce performance degradation of electrical connector are determined. Then, the simulation test methods on ground and data analysis methods are formulated to research performance degradation rules of electrical connector in space environment.In Chapter 6, the performance degradation mechanism of electrical connector under the multiple stresses of vacuum-temperature-current-voltage is analyzed. The reliability model of thermal-vacuum environment based on performance degradation process is formulated. Then, the modeling method based on performance degradation mechanism and degradation data analysis is discussed for space environment reliability of electrical connector.In Chapter 7, the reliability statistical model based on degradation data is formulated and proved for electrical connector under thermal-vacuum environment. The corresponding estimation techniques for model parameters are formulated. The reliability of electrical connector under thermal-vacuum environment is assessed.In Chapter 8, the works of this dissertation are summarized; suggestions for further research are proposed.