Determination of energy dissipation during cyclic loading and its use to predict fatigue life of metal alloys

An approach to determine the specific energy dissipated during cyclic loading of metal alloys with load ratios between 0 and 1 is developed. The dissipated energy per cycle is determined by using a limiting procedure to obtain the area enclosed between successive loading and unloading curves and can be used for low-, medium-, and high-cycle fatigue. Comparisons with published data from two aluminum, one titanium, and one steel alloy show that the predictions capture the test results very well. A universal curve relating cycles to failure to two nondimensional parameters is derived. It is shown, in some limiting cases, that the method leads to power law equations with the parameters in these equations determined directly from the complete stress–strain curve of the material with no need to fit experimental data. Furthermore, if certain conditions are satisfied, the method is consistent with the existence of an endurance limit and Miner's rule.