PSI - Issue 19

Giovanni M. Teixeira et al. / Procedia Structural Integrity 19 (2019) 175–193 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Figures 17, 18 and 19 show the PSDs obtained from the measured accelerations on the directions X , Y and Z . These PSDs are converted into stress PSDs by the transfer functions (FRF) when the fatigue analyses are performed in the frequency domain. Although the measured accelerations show stationarity and ergodicity, Gaussianity is not always guaranteed. Aiming for a fair comparison between time and frequency approaches, the input accelerations used in the time domain analyses were obtained from the realization of the following PSDs (Fig. 17-19), which ensures the spectral moments ( m 0 , m 1 , m 2 , m 4 ) from the inputs are equivalent in both domains.

Fig. 17. PSD from the accelerations measured at the X direction.

Fig. 18. PSD from the accelerations measured at the Y direction.

Fig. 19. PSD from the accelerations measured at the Z direction.