振动疲劳载荷谱编制与试验验证

Vibration fatigue load spectrum compilation and test verification

根据雨流计数法、快速傅里叶变换方法和Miner法则,提出了基于时域和频域概念的振动疲劳载荷谱编制原理,并进行了2种航空材料的时域和频域振动疲劳载荷原谱和加速谱对比试验,验证了编谱方法的有效性。建立了某型飞机平尾结构有限元分析模型,进行了振动疲劳载荷识别,再采用提出的振动疲劳编谱方法,编制了某型飞机平尾结构的振动疲劳载荷原谱和加速谱,用于全尺寸振动疲劳试验。平尾振动疲劳编谱结果表明:振动载荷原谱和加速谱下平尾疲劳损伤相对偏差小于5%,加速效率高达80%,可大幅降低试验成本。

Time-and frequency-domain methods are proposed to compile actual and accelerated vibration fatigue load spectrums by incorporating rain-flow counting algorithm, Fast Fourier Transform(FFT) and Miner rule. Comparative vibration fatigue tests(in axial and lateral direction) are conducted on two kinds of aeronautical metals under actual and accelerated time-and frequency-domain vibration fatigue load spectrums, demonstrating the practice and effective usage of compiling methods. After this, finite element model is generated to calculate the correlation between acceleration response and vibration loads of an aircraft horizontal tail, and the validity of finite element model is verified through modal analysis. Then, actual and accelerated vibration fatigue load spectrums of horizontal tail are compiled for full-scale vibration fatigue tests using the above compilation method. It is shown that the relative deviation between fatigue damage resulted from actual and accelerated vibration fatigue load spectrums is less than 5%, but accelerated efficiency is about 80%.