| The aerospace industry,with the characteristics of high investment,technologyintensive,and high-reliability requirements,is an important national strategic pioneer industry.It is a comprehensive reflection of the economic,military,and technological level of a country.To ensure the success of space launch missions,the space launch site equipment provides technical support and service.The equipment at the space launch site is highly technical and complicated.The reliability of the equipment in the space launch site directly affects the success of the launch mission.Modeling and evaluating the reliability and health status of equipment at launch sites can identify and eliminate the potential risk of mission launch caused by equipment failure.Systems in aerospace field have long lifetime,leading to insufficient failure data.Additionally,most subordinate modules are self-developed,and reliability models of components at each physical level may not be clearly defined.The existing reliability methods assuming sufficient failure data and well-known failure mechanisms,cannot be directly used in the aerospace field.The dissertation aims to develop a suite of methods and tools to facilitate the reliability modeling and assessment of equipment at the space launch site.The research contributions of this dissertation are summarized as follows:（1）Developing reliability modeling and assessment strategies from component level to system level.A standardized method is proposed to address the problem of scattered reliability data storage and nonstandard data collection.To overcome the problem of insufficient failure data as a result of the high reliability of space launch site equipment,a component reliability assessment is conducted by utilizing manufacturing report,national standards,industry information,historical failure data,and performance degradation data,as well as a reliability prediction method and reliability model parameter estimation method.The equipment reliability assessment method is,then,carried out to assess the equipment reliability based on information such as component life model,maintenance model,commissioning time,and historical maintenance data.（2）Proposing a fuzzy-analytic hierarchy process to assess the health status of launch site equipment.A hierarchical evaluation of equipment health status is constructed for radar equipment.By using fuzzy hierarchical analysis,the health status of radar equipment can be assessed by expert experience and equipment performance indicators.A new importance metric is developed to quantify the contribution of each health indicator to the system health status.（3）Developing of the launch site equipment reliability assessment software.The software modularizes all the proposed methods for reliability and health status assessment,and it also contains user management module,reliability data module,equipment reliability modeling and equipment health status assessment module.With friendly graphical user interface,the software can considerably improve the efficiency of reliability analysis. |
