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针对单晶涡轮叶片热机械疲劳(TMF)问题,围绕单晶涡轮叶片TMF试验,结合单晶变形、损伤理论及数值模拟,建立了一套单晶涡轮叶片TMF寿命评估方法.利用空心气冷涡轮叶片TMF试验系统,对单晶涡轮片考核截面在服役条件下所产生的交变应力场和交变温度场进行模拟,确定了裂纹萌生部位及其TMF寿命.考虑单晶涡轮叶片变形和损伤行为的特征,分别建立了基于滑移系的Walker黏塑性本构模型和基于临界平面的循环损伤累积(CDA)模型.利用上述本构和寿命模型,完成了单晶涡轮叶片TMF试验的数值模拟.结果表明:叶片理论危险点与试验结果一致,且计算寿命基本落在试验寿命的3倍分散带内.
Aiming at the TMF problem of single-crystal turbine blade, a set of TMF life assessment method of single-crystal turbine blade is established around the single-crystal turbine blade TMF test, combined with single crystal deformation and damage theory and numerical simulation. Blade TMF test system to simulate the alternating stress field and alternating temperature field produced by the test section of single-crystal turbine blade under service conditions, and to determine the crack initiation site and its TMF lifetime.Considering the deformation and damage behavior of single crystal turbine blades The Walker visco-plastic constitutive model based on slip system and the cyclic damage accumulation model based on critical plane (CDA) are established respectively.The numerical simulation of TMF test of single crystal turbine blade is completed by using the above constitutive model and lifetime model. The results show that the theoretical critical point of the blade is consistent with the experimental results, and the calculated life is basically within 3 times of the test life.