基于DFR的2024-T3铝合金当量加速关系试验研究

目的 提出以反映结构材料疲劳性能的DFR为表征参量，研究建立2024-T3铝合金结构在大气自然环境预腐蚀与实验室加速试验预腐蚀后的DFR关系，为腐蚀环境下飞机铝合金结构的疲劳寿命设计提供方法。方法 以2024-T3铝合金试验件为研究对象，分别开展典型海洋大气环境自然暴露腐蚀后的DFR试验以及实验室加速腐蚀试验后的DFR试验，以DFR相等为条件，建立上述2种不同预腐蚀条件之间的DFR当量加速关系。结果 2024-T3铝合金在自然暴露预腐蚀环境与实验室加速预腐蚀后的DFR值随腐蚀时间的增加均有不同程度的下降，万宁和青岛的DFR当量加速值分别为0.642 1、0.701 2 a/d。结论 基于DFR的当量加速关系综合反映了预腐蚀对结构材料疲劳性能退化的影响，而DFR是飞机结构疲劳设计的基本参量，文中建立的当量加速关系可用于指导腐蚀环境下铝合金的疲劳寿命设计分析。

Experimental Research on Equivalent Accelerated Relationship of 2024-T3 Aluminium Alloy Based on DFR

The work aims to take DFR that reflects the fatigue performance of structural materials as a characterization parameter to study and establish the DFR relationship of 2024-T3 aluminum alloy structure after pre-corrosion in natural environment and accelerated laboratory test, so as to provide a method for fatigue life design of aircraft aluminum alloy structure in corrosive environment. With 2024-T3 aluminum alloy test piece as the research object, the DFR test after natural exposure corrosion in typical marine atmospheric environment and accelerated corrosion in laboratory was carried out respectively. On the condition that DFR was equal, the DFR equivalent accelerated relationship between the above two different pre-corrosion conditions was established. After natural explosion in pre-corrosion environment and accelerated pre-corrosion in laboratory, the DFR of 2024-T3 aluminum alloy decreased to different degrees with the increase of corrosion time, and the DFR equivalent accelerated values in Wanning and Qingdao were 0.642 1 a/d, and 0.702 1 a/d, respectively. The equivalent accelerated relationship based on DFR comprehensively reflects the effect of pre-corrosion on the fatigue performance degradation of structural materials. DFR is the basic parameter for the fatigue design of aircraft structure, and the equivalent accelerated relationship established can be used to guide the fatigue life design and analysis of aluminum alloy in corrosive environment.