【作者】 黎方学； 饶寿期；

【Author】 Li Fangxue Rao Shouqi Beijing University of Aeronautics and Astronautics

【机构】 北京航空航天大学；

【摘要】 单晶合金涡轮叶片,由于高温性能优于多晶合金,现已广泛地应用在航空发动机的热端部件中。它是正交各向异性材料,本构模型复杂,研究这种叶片的热弹性蠕变行为是非常必要的。R.Hill提出了具有三个相互正交对称平面的广义Von-Mises屈服函数。这种函数及其流动法则是各向异性材料最广泛的应用公式,并已编制成非线性有限元通用程序如MARC程序。本文应用MARC程序对复杂的单晶气冷涡轮叶片进行了非线性的热弹性蠕变分析。首先,对我国生产的镍基合金试件在不同的温度和应力状态下进行蠕变试验,获得了蠕变曲线;根据Norton蠕变律,由曲线拟合了蠕变常数A、n、p值。根据单晶材料的工程常数及叶片的温度场,计算了叶片的热弹性应力分布;由Hill理论及其屈服准则完成了非线性蠕变分析,得出了在2000小时后叶片的蠕变应力松弛曲线及应变曲线。这个计算结果对设计和发展单晶气冷涡轮叶片是具有实际意义的。更多还原

【Abstract】 Single crystal turbine blade have been used extensively at the hot section of air-engine, because their high temperature properties are Superior to those of polycrystalline alloys. Single crystal alloys is orthotropic material and constitutive model is complacated. It is necessary to develop a model to predict the inelastic constitutive behavior of blade. R. Hill proposed a generatization of the von-Mises yield function for materials having three mutually orthogonal planes of symmetry, This yield function is the most widelly used formulation for anisotropic material and has been coded into general purpose nonlinear finite element codes such as MARC. In this paper, nonlinear thermoelasticity creep is analysed for single crystal alloy air-cooled turbine balde with complicated constitution by MARC code. First, creep testing on the single crystal nickel-base alloy specimens in made China at various temperature and stresses was carried out and getting the creep curves. In addition to this, the creep constant A. n. p sabtained on Norton’s law by fitting the curves. According to Hill’s theory and corresponding yield criterion, nonlinear creep analysis was performed for the blade and getting creep stress relaxation curves and creep strain curves at 2000 hours The obtained results are of practical significance for designing and developing single crystal air-cooled turbine blade.更多还原