When using different fatigue life estimation methods or fatigue damage estimation methods for a given load cycle, the experimental data for a given material must be acquired first.
In this master's thesis we discussed energy models for fatigue damage calculation and compared them with stress and strain models, with the purpose of studying different methods and their comparisons with well-established stress and strain methods. In addition, we compared several mean stress corrections methods whose formulation is based on energy of closed hysteresis loop. Next we simulated stress strain states for the selected load cycles and calculated the corresponding fatigue damage. Additionally we discussed viscoplastic models that include the effects of time component on the fatigue life to further evaluate the efficiency of energy models. We started the process of evaluating energy models on the basis of obtained experimental data of fatigue life measurements, which is available in the published literature. Next we calculated all model parameters and estimations of fatigue life for each discussed model and correction.
We have found potential in usage of energy models, due to comparable results with strain models, and in certain cases the results were even more accurate and with less scatter.
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