Metal Fatigue-Limit Estimation Based on Intrinsic Dissipated Energy

Abstract

Fatigue-limit estimation of engineering materials through thermographic methods has been improved for reliable prediction. In this study, the fatigue limit for STS304 austenitic stainless steel was estimated at load frequencies of 1 and 5 Hz on the basis of the surface temperature change and intrinsic dissipated energy. The sensitivity of STS 304 steel to fatigue damage, the deviation of the measurement data, and the determination coefficient of the predicted fatigue limit were measured at various stress amplitudes through a fatigue test. When the intrinsic dissipated energy was adopted as an indicator, it significantly improved the damage sensitivity and the reliability coefficient in comparison to the surface-temperature change. The intrinsic dissipated energy behavior at 5 Hz predicted a reliable fatigue limit, in which the predicted limit value was approximately 10% lower than that obtained by the staircase method.