摘要
飞机重心过载谱的低载截除水平不能像应力谱那样可以根据结构材料的疲劳极限直接确定,而通过疲劳试验设计和分析,可以获得准确的疲劳损伤变化趋势,进而确定过载谱低载截除水平。用不同的截除水平依次截除原始过载谱从而得到一系列过载截除谱,加速后在MTS810疲劳试验机上对标准试件进行周期加载,从各组试件疲劳寿命的变化趋势中寻找规律并确定最佳截除水平点。试验结果表明,对于某型直升机的过载谱,其循环数量截除水平点可以确定为300次/飞行小时,对应的过载门槛值截除水平点为0.086 2g。疲劳试验不仅提供了确定过载谱低载截除水平的途径,还揭示了随机谱中略小于疲劳极限的个别循环仍可以产生疲劳损伤的事实。
It is impossible to determine the small load cycle elimination level of aircraft G-factor spectrum at the centre of gravity （CG） as convenient as stress spectrum, because the fatigue limit in the form of G-factor does not exist.. Through fatigue test design and analysis, the tendency of the fatigue damage is obtained. It is the key step for determining G-factor spectrum elimination level. The test is carried out on a MTS810 test machine, and the spectra are obtained by eliminating small cycles at different levels and accelerating the remaining cycles with a certain relation. The best elimination level exists at the start point of the flat part of the life tendency curve. For a certain type of helicopter, the level is about 300 cycles per flight hour in cycle quantity form and 0. 086 2g in G-factor threshold form. The fatigue test can determine the small load cycle elimination level of G-factor spectrum, and reveals that a few cy- cles in the random spectrum below the fatigue limit still generate fatigue damage.
出处
《南京航空航天大学学报》
EI
CAS
CSCD
北大核心
2010年第3期343-346,共4页
Journal of Nanjing University of Aeronautics & Astronautics
关键词
过载谱
低载截除水平
疲劳试验
疲劳极限
G-factor spectrum
small load cycle elimination level
fatigue test
fatigue limit
