A new look at the effect of bandwidth and non-normality on fatigue damage

A new attempt is made in this paper to quantify the effect of bandwidth and non-normality in fatigue damage analysis. For the lack of actual stress history, a series of non-Gaussian and homogeneous random processes are generated with fast Fourier transform (FFT) acceleration. A factor is defined on the basis of rain-flow counting and Palmgren-Miner rule to correct the narrow band and normality assumption. It is revealed that the fatigue damage evaluated through the traditional method may be either conservative or rather unconservative. The upper and lower bounds of the correction factor are studied with respect to kurtosis and skewness of the generated random process and the slope of S-N curve.