民用飞机气密腹板主要承受机舱内部的气密载荷，气密腹板在面外气密载荷循环作用下可能发生疲劳破坏，产生裂纹，为研究气密腹板的疲劳性能，提出了一种裂纹预测分析方法，并通过疲劳试验验证方法的可行性。根据飞机气密腹板结构的传力特征和试验测量结果，确定了气密腹板疲劳典型部位和循环受载严重工况。选取疲劳典型部位腹板格子（包含连接紧固件），以六面体单元为最小单元建立精细有限元模型，进行仿真分析，分析得到裂纹发生位置以及裂纹发生机理和实际检测结果一致。基于细节疲劳额定值（detailed fatigue rating，简称DFR）法和疲劳检查表，进行气密腹板疲劳寿命分析，采用NASGRO软件进行气密腹板裂纹扩展寿命分析，裂纹萌生并扩展到临界裂纹长度的疲劳试验循环次数接近裂纹发现时次数，且理论分析偏保守。
As the airtight web of civil aircraft is located in the airtight area and mainly bears the pressure load inside the cabin, fatigue failure and crack may occur in the web of civil aircraft under cyclic loading. In order to study the fatigue performance of the airtight web, a method of crack prediction was proposed and verified by the fatigue test. According to the force transmission characteristics and test results of the airtight web structure, the typical fatigue parts and the severe cyclic loading conditions of the airtight web were determined. The web grid of typical fatigue parts (including connecting fasteners) was selected, and the hexahedron element was taken as the smallest element to establish a fine finite element model.The simulation analysis was carried out, and the crack location and mechanism were obtained, which were consistent with the actual situation. Based on the detailed fatigue rating(DFR) and the fatigue checklist, the fatigue life of the airtight web was analyzed. And the crack growth life of the airtight web was calculated by NASGRO software. The fatigue test cycle number of crack initiation and propagation to the critical crack length were close to the real flights when discovering the crack, and the theoretical analysis was conservative.
赵鑫.民用飞机气密腹板裂纹研究[J].民用飞机设计与研 究,2021(2):94-99ZHAO Xin.[J]. Civil Aircraft Design and Research,2021,(2):94-99. ( in Chinese)复制