Abstract: To meet the rapid design and assessment requirements of structural durability (fatigue) analysis for military aircraft development in the preliminary design stage, characteristic differences between military aircraft and civil aircraft are summarized, and detail fatigue rating (DFR) approach suitable for military aircraft structure and service load is presented. Based on principle and technology of civil aircraft DFR approach, assuming that fatigue life follows logarithm normal distribution, some pivotal problems with military aircraft characteristics are studied, such as determining constant load amplitude equivalent to random load spectrum, structural DFR allowable value, specific S--N curve, engineering implement process of DFR approach, etc. Preliminary application shows that it is feasible and conservative, can significantly shorten development time and reduce cost during the initial durability design of military aircraft. It has important engineering significance and application value.

Key words: military aircraft, structure, fatigue, durability, detail fatigue rating, statistical distribution