A new fatigue cumulative damage model based on material parameters and stress interaction

Abstract

In order to evaluate the fatigue damage accumulation process of materials under different stress levels and to predict the fatigue lives, a new fatigue accumulation damage model based on material parameters and stress interaction is proposed. The parameters of the material required for the action coefficient introduced by the proposed model are the slope of the S-N characteristic curve and the ultimate stress. In addition, the fatigue cumulative damage of the previous level and the ratio of adjacent stresses are also taken into consideration. Besides, we have conducted extensive experiments by utilizing the two-level stress experimental data of steel 300CVM, 16Mn steel, LY12CZ, and AL-2024-T42, the three-level stress experimental data of LY12CZ material, the four-level and five-level stress experimental data of Aluminum alloy material, respectively. Especially, we calculate and compare the fatigue prediction results of our proposed model with those of the 6 existing models, i.e., Manson-Halford model, YG model, Yue model, Haghgouei model, Subramanyan model and Hashin model. These materials used for verification, in addition to the fatigue test data of high cycle lives, also include the combination of high cycle and low cycle multi-level stress test data. Finally, we compare the cumulative fatigue life of each model via two-level to five-level stress tests, and calculate the difference between the fatigue damage prediction results and the test results to evaluate the advantage of the proposed model. The predicted results show that the model proposed in this paper is in great agreement with the real testing results. Besides, the prediction effect of the proposed model is significantly superior to that of the existing 6 models, especially when both the fatigue low-cycle and high-cycle mixed stresses are used, which validates the high robustness of the proposed model under various complex stress conditions.