Characterization of Fatigue Dynamics Under Deterministic and Stochastic Excitation

Estimating and tracking dynamics of crack growth is essential for fatigue failure prediction. A new experimental system coupling structural and crack growth dynamics was used to show fatigue damage accumulation is different under chaotic and stochastic loading, even when both excitations have similar spectral and statistical signatures. Furthermore, conventional rain-flow counting method considerably overestimates damage in case of chaotic forcing. Important nonlinear loading characteristics are identified to guide the new fatigue model development.