“加快大型飞机研制”是国家“十三五”计划实施的百个重大工程之一，高强铝合金的搅拌摩擦焊技术作为飞机重要结构件的一种制造新技术，它的质量要求关系着人们的生命安全，而且已达到国家战略的高度。针对目前高强铝合金搅拌摩擦焊接头疲劳失效问题、小裂纹扩展机理及疲劳寿命预测理论还需要深入研究和发展，本项目以飞机常用高强铝合金材料的搅拌摩擦焊接头为研究对象，以建立搅拌摩擦焊接头疲劳寿命预测理论为目标，以接头的高周疲劳失效及小裂纹扩展研究为基础，系统研究搅拌摩擦焊接头疲劳薄弱区域预测模型和小裂纹扩展定量描述模型等关键科学问题，通过试验数据进行理论验证，提出一种基于小裂纹扩展理论的搅拌摩擦焊接头疲劳寿命预测方法，为服役的搅拌摩擦焊焊接关键结构部件提供准确的疲劳寿命预测，为重大设备的安全使用提供理论和技术支撑。

“Speed up the large aircraft development” is one of the 100 major projects on the implementation of 13th Five-Year Plan in our country. As a new technology of manufacturing aircraft structural parts, the friction stir welding technology of high strength aluminum alloy relates to people's lives. Its quality has already been brought into national strategy. Aiming at the deep research and development of the issues of fatigue failure, small crack propagation and life prediction method, in the project with the friction stir welded joints of high strength aluminum alloy as the research project, establishing the fatigue life prediction method as the goal, based on the study of high-cycle fatigue failure and small crack propagation, the key scientific issues of models of fatigue weak area prediction and small crack propagation are studied in the project. A fatigue life prediction method for the friction stir welded joints is proposed based on the small crack propagation method which is verified with the test data to provide precise fatigue life prediction for the important friction stir welded structure components in the service and offer theoretical and technical support for the safe use of important equipment.