用于单晶叶片应力分析的滑移本构模型

Analysis on the Crystallographic Slip Constitutive Models for Single Crystal Turbine Blade

关键词:  晶体滑移  切线系数法  牛顿拉弗森迭代  弹塑性本构  正交各向异性  镍基单晶合金

Key words:  Crystal slip  Tangent modulus method  Newton-Raphson iterative method  Constitutive laws for elastic-plastic  Orthotropic  Single crystal nickel base superalloy

摘要:

为了建立适用于镍基单晶涡轮叶片的有限元分析平台,基于有限变形晶体滑移理论和有限元软件ANSYS接口参数要求,导出了增量型本构方程公式。采用变刚度法,以切线系数法为初值,采用局部牛顿拉弗森迭代解法,编制了晶体弹塑性滑移本构模型程序,并以子程序Usermat的形式植入ANSYS软件。计算模拟了DD3试棒不同取向的单向拉伸和循环应力应变过程,讨论了〈011〉方向上的应变软化行为和该本构模型对DD3镍基单晶涡轮叶片的良好应用性。数值仿真结果与实验数据对比吻合良好,验证了程序的正确性。

Abstract:

Based on the dislocation slip theory and the requirement of finite element software ANSYS interface parameters, the incremental constitutive equation formula was derived. On account of variable stiffness matrix method, the program of the crystallographic slip constitutive models was compiled, using the Newton-Raphson iterative method with the result of tangent modulus method as the initial value. The program was implanted into ANSYS in the form of subroutine-usermat, and the engineering application platform was built. Stretching in different orientations and cyclic stress-strain of the DD3 test specimens were simulated. The strain softening behavior in the 〈011〉 direction and the application of this constitutive model in DD3 nickel-based single crystal turbine blade were discussed. The simulating results match with the experimental data well, which certifies the accuracy of the program.