涡轮叶片-榫头-轮盘的蠕变与低循环疲劳寿命预测

Creep and Low Cycle Fatigue Life Prediction for Turbine Blade-Tenon-Disk Structure

为获得小型涡扇发动机的涡轮转子结构的预期寿命,通过对涡轮叶片-榫头-轮盘结构进行一体化建模,利用经典寿命预测方法对其蠕变持久寿命与低循环寿命进行了预测。首先,分析了各部位温度分布和应力-应变分布,确定寿命关键点,利用Larson-Miller方程计算叶片的蠕变持久寿命,然后采用Manson Coffin方程计算整个结构的低循环疲劳寿命。计算结果表明,由于载荷剖面下的工作温度较低,叶片的蠕变损伤极小,而由于榫头/榫槽部位存在应力集中,其低循环疲劳预期寿命仅有102次循环。

Concerning about a turbine rotor in a small turbofan engine,the creep life and low cycle fatigue （LCF）life were predicted by classical life prediction methods,based on integrated modelling of blade-tenon-disk structure. Firstly,temperature field analysis and stress-strain analysis were performed to determine the key points of life. The creep life of blade was predicted by Larson-Miller creep equation and LCF life of whole structure was predicted by Manson Coffin equation. The results show that the creep damage of blade is minimal ,since the working temperature is relatively low under the load spectrum. However,the LCF life of tenon and mortise is only 102 cycle number due to stress concentration.