两级复合载荷下铝合金疲劳寿命预估

Fatigue Life Prediction of Aluminum Alloy under Two-stage Combined Cycle Loading

高低周或低高周复合载荷作用下的疲劳破坏广泛存在于飞机发动机等结构中。基于多机制损伤耦合模型,分别建立了高低周、低高周两级加载下金属疲劳寿命预估模型。通过LY12CZ铝合金两级加载疲劳试验对提出的低高周复合疲劳寿命预估模型进行了验证,并将其与Miner线性模型进行了对比。结果表明:提出的低高周复合疲劳寿命预估模型预测结果更为准确。

Fatigue failure under two-stage combined cycle loading is widely found in aircraft engines and other structures. Based on multi-mechanism damage coupling model,life prediction models of metal fatigue life under two-stage combined loading were established. The proposed model for low and high combined cycle fatigue was verified by experimental data on LY12CZ aluminum alloy under combined cycle loading. Comparison of the proposed model with the model based on Miner theory was also made. The results showed that the predicted life of the proposed model was better correlated with experimental data.