Continuum Damage Mechanics Applied to Fatigue Life Prediction

Cumulative fatigue damage analysis is essential for predicting the service life of structural components and mechanical parts exposed to real-world loading histories. This paper proposes a nonlinear cumulative fatigue damage model based on continuum fatigue damage theory. The model incorporates the effects of fatigue limit, mean stress, and the coupled (non-separable) relationship between damage variables and loading parameters. As a result, it is also able to account for load sequence effects during fatigue accumulation. To evaluate the model’s accuracy and applicability, experimental results for ۳۰CrMnSiA steel under two-level stress loading, obtained from published literature, were used for validation. The predicted fatigue lives produced by the proposed approach show strong agreement with the reported experimental data. A notable advantage of the model is that its material constants can be identified solely by fitting Basquin’s law from the S–N curve, which is widely available for most engineering materials. In addition, the model’s simple mathematical structure makes it convenient and practical for engineering fatigue life prediction applications.

کلیدواژه ها:

fatigue ، cumulative damage ، continuum damage mechanics ، loading sequence effect ، mean stress