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.

复合材料结构的损坏会随着时间的推移而累积，并在实际使用环境中导致疲劳失效。因此，建立合适的疲劳寿命预测模型至关重要。这项工作基于等效损伤和载荷相互作用的影响开发了一种改进的疲劳寿命预测模型。使用复合材料承受二次和三次载荷的测试数据对改进的疲劳寿命预测模型进行了验证和比较。分析表明，损伤等价预测模型考虑了载荷施加顺序和载荷相互作用的影响，提高了变幅载荷下复合材料疲劳寿命预测的准确性。此外，