LAUSR

The kurtosis of stress response significantly affects the fatigue failure time of structures under nonstationary excitation, making it a vital parameter for characterizing the study of fatigue damage caused by nonstationary vibrations. However, the existing methods have not yet considered the assessment of response kurtosis when the structural modal damping is low, which poses a hindrance to the advancement of vibration fatigue acceleration theories. This study focuses on analyzing the envelope characteristics of the response of linear structures under nonstationary excitation produced by the amplitude modulation method. A novel approach is proposed to assess kurtosis by leveraging the envelope curve of the nonstationary signal response. The simulation results demonstrate that the frequency resolution of signal sampling also impacts the response’s kurtosis. The proposed method offers an accurate evaluation and rapid control of response kurtosis in both numerical and experimental examples.