Fatigue Life Prediction by Modified Aeran Model Based on Loading History and Average Stress

Aiming at problems of fatigue damage and life prediction of structures under variable amplitude loads, based on the nonlinear cumulative damage theory, the Aeran model was modified by introducing a load interaction factor and a real-time load function related with stress levels. The Aeran nonlinear fatigue cumulative damage model considering loading histories (including load interaction and loading sequence) and average stresses was established and verified with fatigue test data of 30CrMnSiA steel, 45 steel and 16Mn steel under two-stage loading.The prediction results by the modified Aeran model were compared with those by the improved Aeran model only considering load interaction and Miner model. The results show that the normalized fatigue life predicted by the modified Aeran model and the normalized test results were concentrated near the x=y reference line, indicating the accuracy of the model. Among the three prediction models, the average value and standard deviation of absolute values of the error factor of the modified Aeran model were the smallest, which were 0.042 and 0.131, respectively. These values were 0.021 and 0.035 less than those of the improved Aeran model, and 0.011 and 0.099 less than those of the Miner model, respectively.