The effects of pre-cycle damage on subsequent material behavior and fatigue resistance of SUS 304 stainless steel

Abstract

A series of fatigue tests with type I and type II cycle damage histories were carried out to observe the effects of pre-cycle damage on the subsequent cyclic material response and fatigue resistance. It was found that the applied cycle history of damage leads to an increase in the extent of variation in cyclic hardening/softening. Furthermore, the shape of stable hysteresis loop changes with the type of cycle damage history under the same strain amplitude conditions. This is due to the occurrence of additional cyclic hardening/softening. By comparing the strain–life curves with and without a cycle damage history, it is found that the cycle damage history leads to a decrease in the number of cycles to failure. The loss in fatigue resistance is dependent on the type of pre-cycle damage history. For the fatigue test with a pre-cycle history, an equivalent cycle ration C1⁎ is proposed to predict the residue cycles at the second level in this study. The validity of the modified expression is confirmed by comparing the predicted life results with the corresponding experimental data. It is apparent that the proposed method gives a better prediction than the Miner׳s rule for the two-step histories.