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为了更准确地预估高温材料的低循环疲劳裂纹萌生寿命,将低循环疲劳的裂纹萌生过程视作损伤累积过程,基于连续损伤力学建立了损伤累积模型。结合360℃、650℃下GH4169合金的低循环疲劳寿命数据拟合出模型的具体表达式,进而开展了对低循环疲劳裂纹萌生寿命的预测试验。结果表明:该方法针对GH4169合金低循环疲劳裂纹萌生寿命的预测结果较为理想,其分散带基本在2倍以内,且能很好的反映变幅加载对GH4169合金低循环疲劳裂纹萌生寿命的影响。
In order to predict the low cycle fatigue crack initiation life more accurately, the crack initiation process of low cycle fatigue was regarded as the process of damage accumulation. Based on the continuous damage mechanics, the damage cumulative model was established. Combining with the data of low cycle fatigue life of GH4169 alloy at 360 ℃ and 650 ℃, the concrete expression of the model was fitted, and then the prediction test of the fatigue life of low cycle fatigue crack was carried out. The results show that this method is ideal for predicting the low-cycle fatigue crack initiation life of GH4169 alloy, and its dispersion band is basically within 2 times, which can well reflect the influence of luffing load on the fatigue life of low cycle fatigue crack of GH4169 alloy.