Cumulative damage evaluation in multiple cycle fatigue tests taking into account energy parameters

This work reports fatigue stress test results for AISI 304 steel (R = -1) that has been subjected to a high cycle number. It shows that the energetic effect (employing different temperature increments for equal loading of uniaxial stress) can be used to evaluate the cumulative damage caused by any prior loading. Various load histories were applied to AISI 304 specimens, and the resulting damage was evaluated in reference to the energy factor, Phi, which is dependent on the maximum temperature at the sample surface when irreversible plastic deformation begins. The time curves (Wohler curves) and the damage ratio based on the consumed energy were compared to those obtained according to Palmgren-Miner rules; this comparison served to show how under-evaluations can occur with high damage ratios. (C) 2012 Elsevier Ltd. All rights reserved.