On Fatigue Life Under Stationary Gaussian Random Loads (A)

Abstract

Power spectra are taken to represent stationary Gaussian random loads. Location, scale, and shape parameters are defined for power spectra and proposed as a convenient set of load parameters for random loads. The center frequency of a power spectrum, defined as its weighted average frequency, is proposed as a measure of fatigue life. A servohydraulic closed loop testing machine is used to load specimens of carbon steel under six different power spectral shapes. Test results are utilized to evaluate a fatigue life function formulated in terms of the load parameters. The concept of a shape operator introduced by Weibull for probability distributions, is employed to correlate fatigue lives under different power spectral shapes. Good correlations in the test results are obtained