Fatigue life prediction for broad-band multiaxial loading with various PSD curve shapes

The fatigue calculation procedure analysed here applies the power spectral density (PSD) function of the equivalent stress together with the known spectral method for estimating the probability density function of stress amplitudes included in random loading. Here, the narrow-band approximation, Wirsching–Light, Benasciutti–Tovo and Dirlik models are used, together with the SWT parameter. The prediction capability of these four methods was verified on a set of 107 tests results obtained under random axial, torsion and combined axial and torsion loading applied to a tubular specimen with a one-sided hole. Several PSD shapes and combinations of loading were applied. It is shown that the results for fatigue life calculated using the Benasciutti–Tovo and Dirlik methods are well correlated with the results of experiments under this type of loading.

► Unique multiaxial fatigue tests results (combined axial and torsion random loading).
► Random loading realized with different shapes of PSDs.
► Damage maps for indicating the place of maximum fatigue damage.
► Simple and fast fatigue damage assessment based on spectral method.