Fatigue life due to non-Gaussian excitation – An analysis of the Fatigue Damage Spectrum using Higher Order Spectra

The fatigue damage spectrum (FDS) is an established tool for the assessment of the fatigue damage potential of any kind of vibration loading exerted on vibratory structures. It is especially useful for describing the fatigue damage potential of non-Gaussian random vibration signals, because for this type of signal no comprehensive, theoretically based statistical description is available. As the current definition of the FDS is based on the assumption of single degree of freedom vibration systems, the presented work analyses the resulting limitations for general vibration systems with multiple resonant frequencies. Improvements based on findings from higher-order spectra are proposed.