Vibration fatigue load spectrum compilation and test verification

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%. © 2022 AAAS Press of Chinese Society of Aeronautics and Astronautics. All rights reserved.