DFR法在军用飞机疲劳分析的应用研究

Application of DFR Method in Fatigue Analysis of Military Aircraft

疲劳强度设计直接影响着飞机的经济性与安全性。飞机结构疲劳分析方法分为应变疲劳分析和应力疲劳分析,当军用飞机结构疲劳关键部位应力水平不高、载荷谱中高载所对应的局部应力在材料屈服应力以下时,通常选用应力疲劳分析方法。常用的应力疲劳分析法又被称为应力法、应力严重系数法和DFR法。DFR法主要用于民用客机结构疲劳分析中,军用飞机由于使用方式不同,构成载荷谱的典型飞行任务剖面与民用客机差别较大,导致DFR法不能直接用于军用飞机机体结构疲劳分析中。针对军用飞机使用特点,对DFR法进行改造、优化,使其能够适用于军用飞机机体结构疲劳分析工作中。

Fatigue strength design directly affects the economy and safety of the aircraft. The fatigue analysis method of aircraft structure is divided into strain fatigue analysis and stress fatigue analysis. When the stress level of the critical part of the military aircraft structure is not high and the local stress corresponding to the high load in the load spectrum is below the yield stress of the material, the stress fatigue analysis method is usually used. Commonly used stress fatigue analysis methods are also called stress method, stress severity coefficient method and DFR method. The DFR method is mainly used in the fatigue analysis of civil passenger aircraft structures. Due to the different ways of using military aircraft, the typical flight mission profile that constitutes the load spectrum is quite different from that of civil passenger aircraft. The DFR method cannot be directly used in the fatigue analysis of military aircraft structures. According to the characteristics of military aircraft use, the DFR method is modified and optimized to make it suitable for fatigue analysis of military aircraft structures.