单晶叶片取向相关的统一屈服强度分析方法及应用

考虑非施密特效应提出了等效临界分解剪切应力来统一单晶(SC)合金不同取向的屈服强度。利用5种单晶合金的试验数据,建立了统一的等效屈服准则(EYC),对两种单晶合金非常规取向宏观屈服强度的预测精度在可接受范围内。将晶体学弹性本构模型与EYC编制为ABAQUS/UMAT用户子程序,计算了DD6单晶叶片在873种取向条件下的静强度储备系数。结果表明:取向相关的屈服强度分析方法简单有效,较适于工程应用;所开发的单晶叶片计算工具可快速评估单晶叶片静强度;不同晶体取向条件下该型单晶叶片叶身在最大状态下的静强度储备系数在1.8~2.8之间;此型叶片静强度在一定程度上受到晶体取向随机性的影响,但不同取向下其储备系数都满足准则要求。

Orientation-dependent analysis method of unified yield strength and its application for single crystal blade

Considering the non-Schmitt effect, a concept of equivalent critical resolved shear stress was proposed to obtain the unified values of yield strength of single crystal (SC) superalloy with different orientations. Based on the experimental data of five single crystal superalloys with different orientations, the equivalent yield criterion (EYC) was established. The macroscopic yield strengths of two different SC superalloys with unconventional orientation were calculated and the prediction accuracy was acceptable. The crystallographic elastic constitutive equations and the EYC were coded into ABAQUS/UMAT subroutine. The static strength safety factors of DD6 SC blade with 873 different crystal orientations were calculated. It revealed that: the orientation-dependent EYC was simple and effective, and it was pretty suitable in the application of engineering; the developed calculation tool could evaluate the static strength of SC blade quickly; the safety factor of the blade body under the maximum condition with different crystallographic orientations was between 1.8 and 2.8; the crystal orientation with certain randomness had some effect on the static strength of the studied blade, while the safety factor of the blade body with different orientations met the requirements of the standard.