New Fatigue Life Prediction Model for Composite Materials Considering Load Interaction Effects

Damage to composite structures can accumulate over time and lead to fatigue failure in their actual use environment. Therefore, it is critical to establish a suitable fatigue life prediction model. This work developed an improved fatigue life prediction model based on the effects of equivalent damage and load interactions. Validation and comparison of the improved fatigue life prediction model were carried out using test data of composites subjected to secondary and tertiary loading. The analysis indicates that the accuracy of fatigue life prediction for composites under variable amplitude load is improved by the damage equivalence prediction model, which accounts for the influence of load application sequence and load interaction. Furthermore, a comparison with existing fatigue life prediction models reveals that the proposed model predicts fatigue life more accurately under different amplitude loads.