Fatigue dynamics under statistically and spectrally similar deterministic and stochastic excitations

Abstract

Estimating and tracking crack growth dynamics is essential for fatigue failure prediction. A new experimental system - coupling structural and crack growth dynamics - is used to show fatigue damage accumulation is different under chaotic and stochastic loading, even when both excitations possess same spectral and statistical signatures. Furthermore, the conventional rain-flow counting method considerably overestimates damage in case of chaotic forcing. Important nonlinear loading characteristics, which can explain the observed discrepancies, are identified and suggested to be included as loading parameters in new fatigue models. © The Society for Experimental Mechanics, Inc. 2013.