A hybrid frequency-time domain method for predicting multiaxial fatigue life of 7075-T6 aluminium alloy under random loading

A hybrid frequency-time domain method for predicting multiaxial fatigue life under random loading is developed on the basis of combination of the frequency domain and time domain analysis. The critical damage point of the structure is determined by the frequency domain equivalent stress method. Then, the fatigue life prediction is made in time domain by generating random load-time histories from the power spectral density of the critical point. The method is validated with the random vibration fatigue test of 7075-T6 aluminium alloy. It has been shown that the results of fatigue life calculated by hybrid method are well correlated with the experiment.